Masterblend 4-18-38 Tomato Formula Hydroponic Calculator   v2.1

Extrapolated estimate — ratio-only guess, or derived from a related crop/general principle backed by real academic or extension data

Industry-sourced, not academically verified

Howhydroponics — EC, pH, and PPM Reading Chart for Hydroponics

QP Seedlings — Optimal NPK Ratios, Electrical Conductivity (EC) and pH Levels for Growing Vegetables (initial design inspiration)

Please forward any relevant academic studies to Fred Thompson (see buttons at the bottom of the page.)

This calculator started with a simple need then was expanded with the goal of being as exhaustive/accurate as practical for home gardeners. It was partially vibecoded with claude.ai as a proof-of-concept/demo of how to leverage the "best" of human and AI abilities.

This calculator is based, as much as practical, on concurring academic research. Nutrient ppm is based on weight, NOT derived from EC. (500/640/700 ppm scaling is irrelevant.)

Allium crops require strong cation balance management, especially K–Ca–Mg, not just NPK ratios.

Categorization of fruit and vegetable are culinary, not horticultural.

"Hydroponic" means "nutrient water solution without media nutrient sources."

Urea is neutral, at best, detrimental, at worst, for hydroponics.

Thanks: Saison05 54235345251 Some icons by Icons8 https://icons8.com African violet icons created by Freepik - Flaticon Artichoke icons created by Victoruler - Flaticon Arugula icons created by designhub - Flaticon Asparagus icons created by LAFS - Flaticon Banana icons created by Freepik - Flaticon Basil icons created by Smashicons - Flaticon Belgian endive icons created by Freepik - Flaticon Blackberry icons created by AngDiz - Flaticon Blueberry icons created by Freepik - Flaticon Brussel sprouts icons created by popo2021 - Flaticon Carnation icons created by Freepik - Flaticon Carrot icons created by Freepik - Flaticon Celery icons created by Freepik - Flaticon Chicory icons created by Umeicon - Flaticon Chives icons created by Paul J. - Flaticon Cloud icons created by iconixar - Flaticon (used for the Light column's Shade glyph) Coriander icons created by popo2021 - Flaticon (used for Cilantro) Cucumber icons created by Freepik - Flaticon Duckweed icon, Creative Commons (Wikimedia Commons) Eggplant icons created by justicon - Flaticon Flower icons created by Freepik - Flaticon Food and restaurant icons created by Aranagraphics - Flaticon (used for Beetroot) Gotu Kola icon created by Grok Lettuce icons created by dDara - Flaticon Peppermint icons created by Sea.icon - Flaticon (used for Lemon Balm; same image also used for Mint) Marjoram icons created by Freepik - Flaticon Melon icons created by Freepik - Flaticon Onion icons created by Freepik - Flaticon Oregano icons created by turkkub - Flaticon Parsley icons created by Muhammad_Usman - Flaticon Pawpaw icons created by IYIKON - Flaticon Pea icons created by BZZRINCANTATION - Flaticon Pepper icons created by Smashicons - Flaticon Peppermint icons created by Sea.icon - Flaticon Potato icons created by RIkas Dzihab - Flaticon Radicchio icons created by Victoruler - Flaticon Radish icons created by Futuer - Flaticon Raspberry icons created by juicy_fish - Flaticon Rhubarb icons created by Umeicon - Flaticon Red beans icons created by smashingstocks - Flaticon Rosemary icons created by Backwoods - Flaticon Seedling icons created by Umeicon - Flaticon Shallot icons created by popo2021 - Flaticon Squash, Summer icon created with OpenAI ChatGPT (DALL·E), modified by the author Squash, Winter icon created by Vectorsclub - Flaticon Strawberry icons created by vectorsmarket15 - Flaticon Sun icons created by iconixar - Flaticon (used for the Light column's Full Sun and Partial Sun glyphs) Sweet potato icons created by Freepik - Flaticon Taro icons created by Freepik - Flaticon Tarragon icons created by Freepik - Flaticon Thyme icons created by Freepik - Flaticon Tomato icons created by AomAm - Flaticon Watermelon icons created by Freepik - Flaticon

Extrapolated estimate — ratio-only guess, or derived from a related crop/general principle backed by real academic or extension data

Industry-sourced, not academically verified

Howhydroponics — EC, pH, and PPM Reading Chart for Hydroponics

QP Seedlings — Optimal NPK Ratios, Electrical Conductivity (EC) and pH Levels for Growing Vegetables (initial design inspiration)

Please forward any relevant academic studies to Fred Thompson (see buttons at the bottom of the page.)

Aero-Gro — Recommended EC and pH for Hydroponic Vegetables, Herbs, and Cannabis Agrinula: Jurnal Agroteknologi dan Perkebunan (Ali et al., 2021) — Hydroponic Garlic Production: An Overview

(University of Agriculture, Faisalabad, Pakistan) — full primary PDF reviewed directly (not just secondary description) — Table 4 gives the garlic-specific EC schedule by growth day (1.5→2.5 dS/m) and pH 5.0–6.0, citing Naznin et al. (2009, Eco-Engineering) — basis for Garlic's verified EC/pH, though this session flags a discrepancy against that paper's own stated pH (see below). CORRECTION, REVISED THIS SESSION: Table 2 of this review ("Nutrient mixture for the production of garlic under hydroponic system," also citing Naznin et al. 2009) states NH4-N 2.5, NO3-N 11.5, P2O5 5.2, K2O 7.1, MgO 4, CaO 8.1 mg/L — converting to roughly 14N-2P-6K ppm, implausibly low for any hydroponic feeding solution (even dilute seedling-stage recipes typically run 50+ ppm N). A prior session attributed this to a probable transcription or unit error in the review itself. The primary Naznin et al. 2009/2010 Eco-Engineering PDF has now been obtained and read directly — it states this exact same figure verbatim as its own as-used nutrient solution (see that citation below). REVISED CONCLUSION: Table 2 is an accurate transcription of the primary paper, not a review-introduced error — the implausibly-low figure is genuine to Naznin et al. 2009/2010 itself. It is STILL not used as a source for Garlic's NPK, since the figure remains implausible as a hydroponic feeding target regardless of which document it originates in, but the explanation for why it looks wrong has changed from "review transcription error" to "the primary source itself states an unusually dilute recipe" — still NOT promoted to any displayed cell. UPDATE (earlier session): the review's own introductory sentence — "Naznin et al., (2009) developed the mixture for the production of garlic under hydroponic system which was given below in Tables 2-4" — attributes Tables 2, 3, AND 4 collectively to that same source, even though Table 3 ("General nutrient recipe for the growth of crops grown under hydroponic system," Vegetative 210N-50P-235K / Reproductive 180N-40P-300K ppm) carries no inline citation of its own and is formatted generically by growth phase rather than by named crop. Given that ambiguity, Table 3's Reproductive-growth figure (180N-40P-300K ppm, Ca 170, Mg 50, S 60) is used as Garlic's Bulb- and Mature-stage NPK, but kept at the orange/derived tier rather than promoted to white, reflecting that uncertain provenance. Garlic's Veg-stage NPK no longer relies on any figure from this review — see the Naznin et al. 2020 citation below for that stage's current single source, following this session's unmerge correction.

Ahn, Noh, Kim & Park (2022), Korean Journal of Agricultural Science 49(3):643-653 — Selection of Appropriate Nutrient Solution for Simultaneous Hydroponics of Three Leafy Vegetables (Brassicaceae)

Real, peer-reviewed, semi-DFT rooftop-greenhouse trial (Chungnam National University, Korea) growing Pak Choi (Brassica campestris ssp. chinensis — same species as this calculator's Bok Choy row), Red Mustard/'Red Frill' (Brassica juncea), and Arugula/Rocket (Eruca sativa — matches this calculator's Arugula row) SIMULTANEOUSLY in one bed, testing four real named nutrient solutions (Hoagland, KHE/Korea Horticultural Experiment Station, Otsuka-A, Yamazaki) with complete compositions directly stated (Table 1, mg/L of each salt). All four solutions were adjusted to a shared EC 2.0 dS/m and pH 6.2±0.3 for the co-culture trial, so EC/pH here are experimental constants applied across all solutions/species, not a per-species optimized target. PROMOTES Mustard Greens' NPK to white/verified at 210-31-234 ppm (computed from Table 1's Hoagland recipe: KNO3 606 mg/L total + Ca(NO3)2·4H2O 944 mg/L + NH4H2PO4 114 mg/L + MgSO4·7H2O 492 mg/L, plus micros — a classic, textbook-matching full-strength Hoagland's composition), replacing the prior generic 200-41-280 ppm figure that was an orphaned, mismarked shared placeholder identical to Cabbage/Kale/Swiss Chard's old numbers (see the Spinach citation elsewhere in this file for that placeholder's origin) with zero red-mustard-specific evidence behind it. This is a straightforward gap-fill per this file's standing rule: Hoagland gave red mustard's highest leaf area, fresh weight, and dry weight among the four tested solutions (though not statistically significant) AND its highest total glucosinolate content (34.6 µmol/g, real quality-outcome data) — a real, complete, directly-computable, species-exact, best-performing recipe replacing an unevidenced number. Real corroborating data for Pak Choi and Arugula, NOT applied to override their displayed NPK since both already carry stronger, dedicated, species-specific verified sources: for Pak Choi, Otsuka-A gave the largest leaf area/dry weight among the four tested (real, but Bok Choy's existing Kano et al. 2021 citation above is a dedicated fertilizer-response trial specific to pak choi alone, a stronger source); for Arugula, KHE gave the best growth (leaf length, SPAD, leaf area, fresh/dry weight) among the four, all real but none of the four tested solutions was itself optimized specifically for arugula.

(Ibaraki University, Japan; real, peer-reviewed, species-exact (Brassica rapa var. chinensis) deep-flow-technique hydroponic trial, comparing chemical fertilizer (CF) against corn-steep-liquor organic fertilizer at two rates, across summer and autumn cultivation. The CF (chemical fertilizer) treatment — "conventional hydroponics with a half unit of Otsuka A formula," described as the fertilizer commonly applied in Japanese commercial hydroponic leafy-green production — is directly stated as N-P2O5-K2O 260-120-405 mg/kg, converting to elemental **260N-52P-336K ppm**. PROMOTES Bok Choy's NPK to white/verified, replacing the prior generic, unsourced placeholder (175-36-245 ppm) shared across an unrelated cluster of Brassica crops (Bok Choy, Broccoli, Brussels Sprouts, Cauliflower). Real finding: at this recipe's N level, growth was equivalent to or better than the organic alternatives in both seasons except for a slower summer growth rate under the organic treatment; the paper's real quality finding (lower nitrate, higher ascorbic acid with organic fertilizer at equal N) does not bear on this calculator's feeding-target fields. EC/pH stay sourced separately (Oliveira et al. 2024 for EC, OSU Extension Table 2 for pH, both above) — this paper's own Table 1 gives EC/pH ranges consistent with those sources but does not supersede them since NPK was the more specific and directly convertible figure here.

Akyüz & Ersus (2024), Food Chemistry 453:139647 — Optimization of Hoagland Solution Macro-Elements as a Culture Media, for Increasing Protein Content of Duckweeds (Lemna minor)

Real, species-exact (Lemna minor) optimization study using Plackett-Burman factorial design then response-surface methodology (RSM) on a standard Hoagland base, varying KH2PO4, Ca(NO3)2, and pH to maximize PROTEIN content (not growth/biomass, the objective basis of this row's other sources). KH2PO4 and Ca(NO3)2 were found to be the two most influential macro-elements (contributing 33.06% and 36.61% to the optimization model respectively). Optimal RSM conditions: 3.92 mM KH2PO4, 7.95 mM Ca(NO3)2, pH 7.22 — raising protein content from 33.01% (commercial Hoagland control) to 41.74%. Converts to roughly 121 ppm P and 153 ppm K from the KH2PO4 alone, and roughly 223 ppm N and 319 ppm Ca from the Ca(NO3)2 alone (full baseline composition for the other Hoagland salts, held constant, not given in the abstract — total NPK can't be reconstructed without the full paper). This is a real, dedicated pH data point for Duckweed's pH question (alongside the current display's "peak at pH 7" and Hicks 1932's lower 5.4–6.8 optimum) — notably, 7.22 sits just above both, and is optimized for protein yield rather than growth rate, a different objective than the other two sources. PER FRED'S EXPLICIT CHOICE (2026-07-11), the pH conflict was RESOLVED in favor of the existing 6.0–7.0 (peak at pH 7) figure, now promoted to white/verified — this paper's 7.22 not adopted, kept here as real corroborating/context evidence (the two values are close, and this one reflects a different optimization target, protein density rather than growth).

Alabama Cooperative Extension System (Kessler & Pennisi, 2004), ANR-1257 — Greenhouse Production of African Violets

Real university extension publication (Auburn University / Alabama A&M University; Pennisi is the same UGA horticulture specialist behind the separately-cited UGA Circular 660 on African violets). Gives a staged soluble-salts schedule by crop age: 0.8–1.0 mmhos/cm for young plants, 1.2–1.4 mmhos/cm at roughly 6 weeks post-potting, rising to but not exceeding 1.7 mmhos/cm at finish (with explicit warning that levels above 1.7 enter a "danger zone"); also states a constant fertilization rate of 100–125 ppm N. Roughly consistent with, and corroborating, the OSU HLA-6722 figure of 1.2–1.5 EC adopted above as the basis for African Violet's verified EC — kept here as a second, independent, real source for the same conclusion (African violet needs noticeably more EC than the prior single uncited figure of 0.8 suggested), not used to override the adopted OSU number since the two sources describe the value differently (a single target vs. a growth-stage-dependent schedule) and reconciling them into one figure would require a judgment call beyond what either source states outright.

Alabama Cooperative Extension System — Pawpaw Production Guide

Real, currently-published university extension guide, genus-exact (Asimina triloba). States the ideal pH as 5.5–6.5, citing Missouri research for soil P (90 lb/acre) and K (250 lb/acre) targets, plus a generic annual N rate of 100 lb/acre/year once established — all SOIL/ORCHARD field application rates, not hydroponic solution concentrations, so NOT used for Paw-Paw's NPK or EC figures. The stated pH range (5.5–6.5) is consistent with, and now the basis for widening, the existing single-point pH value (6.5) previously sourced only to Howhydroponics — Paw-Paw's pH is now backed by this real, current, named extension source in addition to Howhydroponics, upgraded from blue to white. An extensive search for genuinely hydroponic pawpaw cultivation literature found none — pawpaw (a slow-growing deciduous understory tree, primarily wild-foraged or small-orchard-grown, with the world's only dedicated research program at Kentucky State University) does not appear to have ever been the subject of a published hydroponic trial. NPK and EC remain unchanged, still blue/Howhydroponics-only.

Alaswad (2023), M.Sc. Thesis, Benha University — Using of Magnetic Water for Irrigation of Plants in Hydroponic Systems

NOT APPLICABLE (confirmed via Fred-supplied direct link, 2026-07-12): the original thesis behind the MISR Journal article on Chicory (see below) — same chicory trial, same author; the thesis is the original and the journal article its later published form. The only additional detail beyond the journal-article extraction is nutrient UPTAKE percentages of N 3.50%, P 0.85%, K 4.32%, Ca 1.96%, Mg 0.31% — tissue content, not feeding concentration, so not usable for this calculator's ppm schema regardless of access. Not a candidate for any NPK/EC/pH field.

Ali, L. (2012), Doctoral Thesis, Swedish University of Agricultural Sciences, Alnarp — Pre-Harvest Factors Affecting Quality and Shelf-Life in Raspberries and Blackberries (Rubus spp. L.)

Real doctoral thesis, four linked papers. Paper II (real, blackberry-specific, greenhouse pot trial, cv. 'Loch Ness', Hasselfors peat substrate, drip-fed) applied a base 14-7-15 NPK ratio fertilizer at two N levels (60/100 kg/ha/yr) and two K levels (66.4/104 kg/ha/yr) across 5 nutrient-regime phases mapped to plant growth stages — genuinely blackberry-specific and staged, but stated in kg/ha with no disclosed application volume, so it cannot be converted to a ppm feed concentration without an assumption this file's Rule 8 does not permit. Not applied to Blackberry's NPK; logged as real corroborating context that a real trial staged blackberry feeding across 5 phases rather than one flat rate. Papers I, III & IV are raspberry-specific (open field/high tunnel/greenhouse comparisons, organic-N-level trial) measuring bioactive-compound and sugar content, not a feeding recipe — not usable as a number source for either row.

Andriolo, Madalóz, Godoi, Janisch & Barros (2008), Ciência Rural 38(4) — Tolerance to Salinity of Chicory Plants Grown in Hydroponics

Real, peer-reviewed, species-exact (Cichorium intybus, cvs. 'Amarelo' and 'Pão de Açúcar') closed-hydroponic sand-bed trial (Universidade Federal de Santa Maria) testing NaCl salinity stress. The paper's own standard (control, T1, no NaCl) nutrient solution is directly stated in mmol/L: NO3- 13.5, NH4+ 2.5 (16.0 mmol/L total N), H2PO4- 1.5, SO4-- 1.5, Ca++ 7.5, K+ 10.0, Mg++ 1.5, plus micros in mg/L (≈224N-47P-390K ppm, Ca 300, Mg 36, S 48), at a real, directly-measured pH 5.8 and EC 2.9 dS/m — the second of two new sources used to resolve Chicory's EC (paired with Oliveira et al. 2023 above; the two real control-EC values, 1.7 and 2.9 dS/m, are now displayed as a range). The paper's own pH management target (5.0–6.0, corrected with H3PO4/NaOH) is close to, but slightly wider on the low end than, the existing 5.5–6.3 range — not used to change the displayed pH, since combining two real but non-identical target ranges is a judgment call. NPK is real, complete, and directly stated but is the highest of the three real Chicory recipes now on file (especially K at 390 ppm, more than double the existing Alaswad/MISR figure) — logged as a real, corroborating-yet-conflicting citation per the same reasoning as the Oliveira et al. 2023 entry above; not used to override the displayed NPK.

Annual Research & Review in Biology (Juárez-Rosete et al., 2014) — Nutrition Assessment of N-P-K in Mint (Mentha spicata L.) Cultivated in Soilless System

(real soilless trial, volcanic-slag substrate, genuinely inert; tested Steiner Universal Solution at 25/50/75/100/125% concentration; 100% gave the best growth from 60 days after transplant onward. This paper's own NPK and EC/pH for the 100% Steiner solution previously anchored Mint's derived figures; NPK and EC have since each been superseded by species-exact sources below (Treadwell et al. 2011 for NPK, Tabatabaie et al. 2007 for EC). pH (5.5–6.5) remains sourced here and stays orange/derived, since it's still a generic Steiner solution applied to mint, not a mint-specific pH finding)

Aqua Gardening — Complete EC & pH Levels Chart for Hydroponic Plants Aquaponics WA / Hydroponic Xpress (Australia) — EC/pH Guide

Real, named, attributable Australian hydroponics retailer (Freecall 1800 640 222), single consumer-facing wall-chart-style EC/pH guide covering ~50 crops across vegetable/fruit/herb/flower categories. Same single-source, non-academic tier as Howhydroponics/HydroHowTo/QP Seedlings elsewhere in this file — useful for filling genuine gaps, not promotable above blue/hh tier. Checked against every existing row in this calculator: its Black Currant/Red Currant figure (EC 1.4–1.8, pH 6.0) and Pineapple figure (EC 2.0–2.4, pH 5.5–6.5) match Currants' and Pineapple's existing values exactly, and its Asparagus figure (EC 1.4–1.8, pH 6.0–6.8) also matches exactly — likely the same underlying source family as the existing Howhydroponics-style attribution on those rows, or at minimum independent convergence from the same genre of consumer reference chart. Added as a second, named, real citation for Currants, Pineapple, and Asparagus's EC/pH (still blue/hh tier — multiple single-source consumer charts agreeing with each other is still not academic verification). Its other crop entries (Bean 2.0–4.0/6.0, Broccoli 2.8–3.5/6.0–6.8, Cauliflower 1.5–2.0/6.5–7.0, Celery 1.8–2.4/6.5, Endive 2.0–2.4/5.5, Eggplant 2.5–3.5/6.0, etc.) were checked against this calculator's existing rows for those crops — all already have stronger, more specific academic citations and were not changed. Also listed a Paw Paw figure (EC 2.0–2.4, pH 6.5) — not applied, since that row was removed from this calculator at the user's explicit request; not re-added on the strength of this single additional source.

Asao, Kitazawa, Washizu, Ban & Pramanik (2005), Journal of Applied Horticulture 7(2):87-89 — Effect of Different Nutrient Levels on Anthocyanin and Nitrate-N Contents in Turnip Grown in Hydroponics

(Shimane University, Japan; real hydroponic trial on Japanese turnip cv. 'Tsudakabu', testing 25/50/75% Enshi nutrient solution strength with full or half NO3-N dose — growth was significantly reduced only at 25% strength, with 50% and 75% performing similarly; computed from the standard Enshi-shoho composition, Hori 1966, the 50% strength tested gives 121N-62P-156K ppm — basis for Turnip's verified NPK. EC/PH ADDED (later session): full-strength standard Enshi-shoho is independently confirmed at EC 2.4–2.5 dS/m, pH 6.8 across multiple real hydroponic papers citing the same Hori 1966 source (melon, wasabi, snap bean, spinach, tomato trials) — scaling to the same 50% strength already used for Turnip's NPK gives EC 1.2–1.25 dS/m; pH does not scale with dilution and stays at 6.8. Real, named, standard-formula-derived figures — basis for Turnip's verified EC and pH, replacing the prior generic, uncredited QP Seedlings placeholders.

Baek, Saeed & Choi (2021), Appl Biol Chem 64:73 — Duckweeds: Their Utilization, Metabolites and Cultivation

Real, genus/family-wide (Lemnaceae) review compiling cultivation conditions across dozens of published duckweed studies (Table 8). States a general "wide pH range of 3.5 to 9.0, and the optimal pH range is between 6.5 and 7.5" and temperature 19–30°C across the family — broader and less species-specific than the existing dedicated Lemna minor pH-response trial already cited above (which found a genuine tested optimum peaking at pH 7, the basis for this row's current 6.0–7.0 range). Every specific recipe tabulated in the review is named only by medium ("1/2 Hoagland," "SH medium," "MS medium") without restating its own composition — same named-formula-without-numbers gap as several other citations in this file. Not applied; the existing more-specific pH source is kept, and the duckweed NPK conflict (previously 24-3-25 placeholder vs. Jin et al.'s 4x-Hoagland finding vs. others) was RESOLVED 2026-07-11 per Fred's explicit choice — see the Petersen et al. 2022 note elsewhere in this file, now Duckweed's displayed, white/verified NPK (14-3-36).

Balik, Dasgan, Ikiz & Gruda (2024), Horticulturae 10(12):1289 — The Performance of Growing-Media-Shaped Microgreens: The Growth, Yield, and Nutrient Profiles of Broccoli, Red Beet, and Black Radish

Real, dedicated, full-primary-text-read six-growing-media comparison trial (Cukurova University/University of Bonn) on Broccoli, Red Beet, AND Black Radish specifically — all three grown on the SAME shared quarter-strength nutrient solution (varying only the growing medium): stated directly in mg/L as N 200, P 50, K 300, Ca 200, Mg 65, Fe 5.0, Mn 0.8, Cu 0.3, Zn 0.3, B 0.3, Mo 0.05; pH 5.5; EC 1.2–1.6 dS/cm. Cites the same author group's companion paper (Balik, Elgudayem, Dasgan, Kafkas & Gruda, "Nutritional Quality Profiles of Six Microgreens," Sci. Rep. 2024) as the source of this recipe — this is very likely the same underlying figure already used for Pea Shoots (200-50-300, sourced from the six-microgreens paper's own reported recipe, which lacked EC/pH; this paper supplies the missing EC 1.2–1.6/pH 5.5 for that same recipe, now applied to Pea Shoots). PER FRED'S EXPLICIT CHOICE (2026-07-10), also now APPLIED to Microgreen - Radish's displayed NPK/EC/pH (200-50-300, EC 1.2–1.6, pH 5.5, promoted to white/verified), on the reasoning that this recipe is shared across only three species with black radish directly tested, a more crop-specific candidate than the previously-displayed Di Gioia-lineage figure (105-16-117), which was shared across 17 species. STILL FLAGGED, NOT APPLIED to Broccoli or Beet's own displayed NPK, which remain on the Di Gioia-lineage figure — this real, dedicated, shared-recipe figure (200-50-300) is substantially higher on N and K than those two rows' current 105-16-117, a genuine conflict between two real sources, neither more crop-specific than the other for Broccoli/Beet specifically (both are "one recipe shared across several species" studies for those two crops). Vermiculite and peat-based media gave the highest yields across all three species in this trial, if substrate choice is ever incorporated.

Barbosa da Cruz, Martins do Carmo, Capato Lima, Evangelista Vieira, Alves Peçanha & Mendonça Freitas (2026), Bioagro 38(1):397-406 — Growth and Phenolic Compounds in Cilantro as a Function of the Ionic Strength of the Nutrient Solution

(Universidade Estadual do Norte Fluminense Darcy Ribeiro, Brazil; DOI 10.51372/bioagro381.1; real, peer-reviewed, species-exact (Coriandrum sativum cv. Verdão SF 177) greenhouse trial, six Hoagland & Arnon (1950) ionic-strength treatments from 25% to 150% (EC 0.5–3.0 mS/cm at 100%=2.0 mS/cm), pH held 5.5–5.8, harvested 60 days after sowing. GROWTH-OUTCOME-VALIDATED EC finding: leaf area followed a quadratic response peaking at 87.4% ionic strength (792.5 cm²) and shoot dry mass peaked at 79.8% ionic strength (3.0 g) — both landing in the EC≈1.6–1.75 mS/cm band, a real, measured-outcome optimum, not just a feed-table target — basis for Cilantro's verified EC (promoted to white, tightened to 1.6–1.75) and pH (promoted to white, 5.5–6.0). NOT used for NPK: the paper's N/P/K/Ca/Mg/S data (Figures 3–5) are dry-tissue nutrient CONTENT in g/kg, not feed-solution concentrations, and cannot be converted to a displayed ppm recipe without the uptake-efficiency assumption this calculator's Rule 8 prohibits.)

Bazangeya, Sbrizzi, Almohimed, Angelova, Bougherara & Campbell (2025), Journal of Berry Research 15(2) — Feeling the Heat: Temperature and Fertilizer's Role in Cooking Up a High Yielding Raspberry Crop (Rubus idaeus) Grown in a Controlled, Indoor, Hydroponic Environment

(Toronto Metropolitan University, Canada; real indoor vertical-farm hydroponic trial, cv. 'Joan J', perlite:vermiculite (3:7) substrate, 210 plants — tested 3 temperatures (21/23/25°C) × 3 fertilizer recipes (A: flat 500 ppm per Treftz & Omaye; B: FloraSeries® weekly "Medium Feed" developmentally-adjusted schedule; C: B + Glomus intraradices mycorrhizae) — Recipe B significantly outproduced A and C on total fruit biomass and harvest index (26–35% more fruit, p<0.03); 23°C gave highest overall yield and sweetest fruit (9.89°Bx) though 21°C gave the largest individual fruit in month 1. Appendix Table A2 gives the full Recipe B weekly nutrient schedule (mg N/P/K per 500 mL application, weeks 1–11) — converted directly to ppm, this is the basis for Raspberry's fully verified Veg/Bloom/Fruit NPK in this calculator. pH was monitored and held at 6.0; EC was not reported by this paper)

Behavior of NPK in Carnation (Dianthus caryophyllus L.) cv. Delphi Growing on a Soilless Crop System with Recycling of Drainage, Journal of Plant Nutrition 46(9) (2022)

UPDATED (2026-07-12, per Fred-supplied full PDF — previously blocked/unreachable). Real, species-exact (Dianthus caryophyllus cv. 'Delphi'), Colombian floriculture soilless greenhouse trial (National University of Colombia, SENA Mosquera), testing 3 substrate mixes (burned rice husk/coconut fiber) × 3 drainage-recycling levels (0/50/100%) on N/P/K behavior in leachate, tissue, and substrate. The paper's Materials and Methods section DOES state its own applied fertigation formula directly, in mg/L (ppm) — something the abstract alone didn't reveal: vegetative phase N 200, P 30, K 150, Ca 150, Mg 60, S 72, plus Zn 0.5, Cu 1, Fe 4, B 1, Mo 0.1; productive phase N 150, P 30, K 150, Ca 150, Mg 60, S 120 (same micros). This is a real, directly-stated, complete, species-exact feed recipe. APPLIED (2026-07-12, per Fred's instruction): Carnation's single Table 2 row has been split into two — Carnation (Veg) 200-30-150 and Carnation (Flower) 150-30-150 (renamed from initial Vegetative/Production labels per Fred, with Veg pinned above Flower via an explicit sort-order override rather than relying on alphabetical order) — replacing the prior single-row derived figure (250-109-208, from a generic 19:19:19 water-soluble fertilizer study, see Singh et al. citation above, now EC/pH-only). EC/pH kept unchanged (2.0–3.5 / 5.5–6.0) on both new rows, still sourced to Singh et al./OSU Extension since this paper doesn't give a fertigation-solution EC/pH of its own (only reservoir/background water chemistry, see below). The paper's own results/conclusions are about recycling's effect on leachate/substrate/tissue N-P-K (not the feed target itself) — e.g. nitrate in leachate rose with higher recycling %, phosphate in leachate rose with recycling % and higher coconut-fiber content, potassium in leachate fell with recycling — useful agronomic context but not itself a ppm target. Table 1 also gives real reservoir/irrigation-water background chemistry (pH 6.4-6.7, EC 0.24-0.90 dS/m, plus Ca/K/Mg/Na/Cl/SO4/HCO3 at each phenological stage) — a water-quality baseline, not the fertigation solution itself, so not used for the displayed EC/pH.

Bloomingreen — pH and EC Levels for Hydroponic Vegetables: 101 Ultimate Guide Bulgari, Baldi, Ferrante & Lenzi (2016), New Zealand Journal of Crop and Horticultural Science — Yield and Quality of Basil, Swiss Chard, and Rocket Microgreens Grown in a Hydroponic System

Real, peer-reviewed, floating hydroponic trial covering three species this calculator already carries (Basil, Swiss Chard, Arugula/Rocket), but at the MICROGREEN growth stage (harvested 17–27 days after sowing, at first-true-leaf/cotyledon stage) rather than the mature-plant stage this calculator targets. All three species shared the SAME generic half-strength Hoagland's solution (N 105, P 15.5, K 117, Ca 100, Mg 24.3 ppm; EC 1.12 mS/cm; pH 5.56) rather than a species-optimized recipe — the paper's own focus is comparing yield/mineral-uptake/quality OUTCOMES across species on an identical feed, not identifying each species' ideal nutrient target. Real finding of note: microgreens of all three species had roughly half the yield, much higher shoot:root ratio, and notably lower nitrate/chlorophyll/sugar content than the same species grown to full maturity. Not used to change any of Basil's, Swiss Chard's, or Arugula's displayed NPK/EC/pH — all three already have dedicated, mature-stage, species-specific verified sources, and this paper's shared non-optimized recipe plus different growth stage make it a "real but different question" citation, the same category as several other microgreen/juvenile-stage sources already in this file.

DOI 10.17660/ActaHortic.1995.396.24. Real, peer-reviewed, species-exact hydroponic EC-response trial covering BOTH Dill and Thyme in the same study. Maximum fresh/dry biomass yield occurred at EC 3.6 dS/m for both crops; for Dill specifically, best essential-oil yield occurred at a lower EC of 2.4 dS/m (higher EC increased biomass but reduced oil concentration per unit tissue). PROMOTES Dill's EC to white/verified, displayed as a range (2.4–3.6) spanning both the oil-yield and biomass-yield optima, replacing the prior unsourced 1.0–1.6 placeholder. PROMOTES Thyme's EC to white/verified at the single max-yield value (3.6), replacing the prior unsourced 0.8–1.6 placeholder — this paper did not report a separate oil-yield optimum for thyme distinct from its biomass optimum. The paper also gives real N:P:K:Ca:Mg absorption (uptake) ratios for both crops (15:2:10:3:2 for dill, 30:5:10:6:4 for thyme) — these are plant-tissue uptake ratios, not feed-solution concentrations, so per this calculator's standing rules they do not change either crop's displayed NPK, which remains unsourced/orange.

Cabanzo-Atilano, Sandoval-Villa, Almaraz-Suárez, García-Cué, Pedraza-Santos & Peralta-Sánchez (2024), Chilean Journal of Agricultural Research 84(1) — Efficiency of Plant Growth Promoting Rhizobacteria (PGPR) in the Vegetative Development of Blackberries (Rubus spp.) in Greenhouse

Real, peer-reviewed, species-exact (Rubus spp., cv. 'Tupy') PGPR-inoculation trial, tezontle-substrate container culture in greenhouse, 78-day juvenile establishment phase (in vitro-propagated seedlings, 7–10 cm at transplant). The nutrient solution itself was NOT the tested variable (rhizobacterial strain was) — a fixed background feed of Universal Steiner nutrient solution at 35% strength, EC = 0.7 dS/m, was applied to all treatments including the uninoculated control, with pH corrected using phosphoric acid. This is the first genuinely species-specific (Rubus/blackberry, not cross-genus-derived from Raspberry) hydroponic-adjacent EC data point found for this row — real and directly stated, but a juvenile-establishment-phase background condition in an unrelated microbiology trial, not itself a tested/optimized mature-plant feeding target, and at 35% strength it sits below (though in the same rough neighborhood as) Blackberry's existing Raspberry-derived Veg-stage EC range (1.2–1.5, itself real per Qiu et al. 2017's finding of no significant EC effect across 0.8–1.6 dS/m in Rubus). Logged as real, genuinely on-topic corroboration; NOT used to override the displayed EC, for the same "incidental background condition, not the paper's tested variable" reasoning already applied elsewhere in this file (e.g. Mint's Sae-Chua CTRL). Strain A46 inoculation significantly increased height (45%), leaf area (110%), shoot dry matter (150%), and nutrient extraction of N/P/K/Ca/Mg/S/B/Cu/Fe/Mn/Zn — a real agronomic finding, but about a soil microbiology treatment, not the base nutrient recipe. No N-P-K composition is given for the Universal Steiner solution itself in this paper.

Campo & Negócios — Hidroponia é a melhor opção para cultivar coentros (interview with hydroponics engineer Rafael Simoni)

(Brazilian agribusiness trade publication; real, named, cilantro-specific commercial salt recipe quoted directly from a named hydroponics engineer, adapted from the Furlani leafy-greens lineage already used elsewhere in this file — g/1000L: calcium nitrate 780, MAP (mono-ammonium phosphate) 150, potassium nitrate 500, magnesium sulfate 420, plus Fe-EDDHA 25–35 and a micronutrient cocktail 10–25. Converted here to elemental ppm using this calculator's standard salt-composition assumptions (calcium nitrate ≈15.5% N/19% Ca; MAP ≈12% N/26.6% P elemental; potassium nitrate ≈13% N/38.2% K elemental; magnesium sulfate heptahydrate ≈9.9% Mg/13% S) since the article itself states salt names and masses but not guaranteed-analysis grades — basis for Cilantro's NPK (204N-40P-191K ppm, Ca ~148, Mg ~42, S ~55). Article gives EC targets of 1.0 mS/cm at nursery/transplant stage rising to 1.8–2.0 mS/cm at production stage. Kept orange/derived rather than white, since the ppm conversion required this calculator's own assumed salt grades rather than the source stating elemental ppm directly, and because the source is trade press rather than peer-reviewed or an approved-industry technical document. Independently corroborated by the Furlani-lineage cilantro/parsley trial cited below under Luz et al. 2012.)

CEAC, University of Arizona — Chapter 10: Fertigation Systems and Nutrient Solutions Chrysargyris, Drouza & Tzortzakis (2017), Journal of Soil Science and Plant Nutrition 17(2) — Optimization of Potassium Fertilization/Nutrition for Growth, Physiological Development, Essential Oil Composition and Antioxidant Activity of Lavandula angustifolia Mill.

(same Cyprus University of Technology hydroponic perlite infrastructure; real K trial testing 275-375 mg/L K alongside the same 200 mg/L N and 50 mg/L P from the 2016 study above — 300 mg/L K gave the best essential oil yield — completes Lavender's verified NPK triplet at 200N-50P-300K ppm)

Chrysargyris, Panayiotou & Tzortzakis (2016), Industrial Crops and Products 83:577-586 — Nitrogen and Phosphorus Levels Affected Plant Growth, Essential Oil Composition and Antioxidant Status of Lavender Plant (Lavandula angustifolia Mill.)

(Cyprus University of Technology; real hydroponic perlite trial testing N 150-250 mg/L and P 30-70 mg/L — explicitly recommends 200 mg/L N and 50 mg/L P for hydroponically grown lavender)

Ciencia y Tecnología Agropecuaria (Frías-Ortega et al., 2020) — Nutrient Solution Concentration and Its Relationship with Blueberry Production and Quality

(Universidad Autónoma de Nayarit; modified Steiner solution — EC >1.0 dS/m harmed growth, production, and fruit quality; EC 0.5–1.0 dS/m optimal — basis for Blueberry's verified EC)

Clemson Cooperative Extension, HGIC — African Violet

(light requirements)

Clemson Cooperative Extension, Home & Garden Information Center — Asparagus, Potato, Sweet Corn, Watermelon factsheets

(light requirements)

Comissão de Química e Fertilidade do Solo — RS/SC, Sociedade Brasileira de Ciência do Solo (2004), Manual de Adubação e de Calagem para os Estados do Rio Grande do Sul e de Santa Catarina, 10th ed., Chapter 19 "Sistemas Especiais de Produção"

(real Brazilian multi-institutional extension manual — EMBRAPA, EMATER-RS, EPAGRI, UFRGS, UFSM, UDESC and others; Section 19.1.3 gives complete NFT hydroponic nutrient solution recipes explicitly used for leafy vegetables including lettuce, arugula, watercress (agrião), and escarole/chicory-type greens (almeirão) in Brazil — Furlani (1998), Instituto Agronômico de Campinas: N-NO3 174 + N-NH4 21 = 195 ppm total N, P 30, K 183, Ca 142, Mg 38 ppm; Castellane & Araújo (1995): N-NO3 255 + N-NH4 9.5 = 264 ppm total N, P 60, K 400, Ca 180, Mg 25 ppm; ideal pH 5.5–6.5 — basis for Watercress's verified NPK/pH (Furlani figure, exact species name match) and Radicchio's derived NPK/pH (genus-level match via almeirão, a related Cichorium species, not an exact radicchio match))

Complete Grow — Hydroponic Nutrients for Herbs

(Basil, Mint, Parsley, Oregano, Thyme, Rosemary, Sage)

Cornell University (Timmons & Mattson, SARE-funded final report, 2019) — Development of Hydroponic Production Systems for Strawberry Production

— used a modified Sonneveld strawberry solution at EC 1250±50 µS/cm, pH 6.0±0.3, with N-rich feed during vegetative/crown stage shifting to reduced-N/increased-P,K at fruit initiation — corroborates Strawberry's staged Yamazaki-based NPK

Cornell University CEA Program — Hydroponic Lettuce Handbook (Brechner & Both, 2013)

— explicit final fertilizer solution: 125N-31P-215K ppm, EC 1150–1250 µS/cm above source water, pH 5.6–6.0 (5.8 optimum) — basis for Lettuce's fully verified NPK and EC/pH; full handbook appendix confirms the two-stock-solution recipe (Stock A: calcium nitrate, ammonium nitrate, potassium nitrate, Fe-DTPA; Stock B: potassium nitrate, monopotassium phosphate, potassium sulfate, magnesium sulfate, micronutrients) and gives matching secondary-nutrient targets: Ca 84, Mg 24, S 35 ppm; Fe 0.94, Mn 0.14, B 0.16, Cu 0.03, Zn 0.13, Mo 0.03 ppm

Cornell University CEA Program — Hydroponic Spinach Production Handbook (Brechner & de Villiers, 2013)

— uses the identical two-stock-solution recipe as the companion Lettuce Handbook above (same Stock A/B formulas, same final result: 125N-31P-215K ppm, Ca 84, Mg 24, S 35 ppm), at EC 1300±100 µS/cm above source water (≈1.3 mS/cm), pH 5.6–6.0, over a 14–16 day floating-pond crop cycle — basis for Spinach's verified NPK and EC/pH, REPLACING a prior generic figure (200-41-280 ppm, EC 1.8–2.3, pH 6.0–7.0) that turned out to be identical to Cabbage, Kale, Mustard Greens, and Swiss Chard's figures — a shared leafy-green placeholder that had been mismarked white/verified despite not being spinach-specific. This Cornell handbook is genuinely species-exact (baby leaf spinach, cv. unspecified, NFT/floating-pond system) and peer-institution-published, same caliber and same lab as the Lettuce Handbook already used elsewhere in this file. Also useful for its detailed Pythium aphanidermatum root-disease management protocol, a documented major barrier to hydroponic spinach specifically that no other source in this registry addresses.

Cornell University — A Recipe for Hydroponic Success (Mattson & Peters, hydroponic-recipes.pdf)

— Table 3 ("Modified Sonneveld Solution for herbs," per Insidegrower/PSU Extension citing this same Mattson & Peters source) gives the full recipe, not just the N target previously extracted: N 150, P 31, K 210, Ca 90, Mg 24 ppm — "Culinary Herbs" category target (production stage), supporting the N value used for Chives, Cilantro, Leek, Lemon Balm, Mint, and Tarragon, with the Ca/Mg figures now also available for any of those rows that lack their own secondary-nutrient data. Table 6 gives a second, independently-sourced staged tomato recipe (224-47-281 ppm weeks 0–6, 189-47-351 ppm weeks 6–12, 189-39-341 ppm week 12+; source: Sunco Ltd./University of Arizona CEAC) cited as a corroborating staging strategy on Tomato's Fruit-stage note. Reviewed again this session per a direct request to check whether Table 2 (lettuce/herbs/leafy-greens one-bag/two-bag commercial fertilizer recipes) or Table 4 (tomato/cucumber/pepper recipes) contain any usable white-cell upgrade for the crops in this calculator — neither does: Table 2 covers the same lettuce/herb/leafy-green category as Table 3 using named commercial products (e.g. Jack's Hydro FeED 16-4-17) rather than a different crop-specific target, and Table 4 covers tomato/cucumber/pepper, all three of which already have independently-sourced, more specific staged recipes elsewhere in this file (Jensen/UA-CEA for Tomato, and existing Cucumber/Pepper citations) that supersede a generic single-stage figure from this table.

Cunha, Chaves, Kano, Braga & Oliveira (2020), Horticultura Brasileira 38:175-184 — Nutrient Uptake Rate for Yardlong Bean

Real, genus-exact (Vigna unguiculata subsp. sesquipedalis) trial, UFAM (Federal University of Amazonas), Manaus, Brazil. A drained-substrate pot-culture system (not pure NFT/water-culture hydroponics) tracking dry-matter accumulation and nutrient uptake by growth stage, with real stated nutrient-solution salts including NH4NO3 and Mg(NO3)2·6H2O at 256.43 g — but the full base N-P-K composition and the dilution volume those salts were dosed into were not found in available search results/snippets, so this could not be converted to a complete, confident ppm figure without guessing at the missing values. Concluded the plant's highest nutritional demand occurs between 20 and 45 days after germination (cited and corroborated independently in the Le et al. 2025 paper used for this calculator's "Beans, Yardlong" row). Kept as real, independent, genus-exact corroborating context; did NOT change the displayed NPK/EC/pH figure, which remains sourced to Le et al. 2025's complete, directly-stated Hydro Umat F composition.

Davis, Lukas, Strik, Moore, Wasko DeVetter, Bryla & Dixon (2024), PNW 780, Oregon State University Extension Service — Nutrient Management of Raspberries and Blackberries in Oregon and Washington

Real, current (Nov 2024), peer-reviewed-level multi-university extension guide covering both raspberry and blackberry. Field/soil agronomy throughout — soil-test sufficiency ranges (Table 1: P 20-30, K 100-200, Ca 500-1000, Mg 50-125 ppm; soil EC below 2 dS/m via saturated paste, a different measurement basis than a hydroponic feed EC) and leaf-tissue sufficiency ranges by 4 fruiting-type/cultivar categories (Table 4: N 2.0-3.0%, P 0.15-0.40%, K 0.8-1.8%, Ca 0.5-1.5%, Mg 0.25-0.60% for both genera) — corroborates, at the leaf-tissue/soil level, the same general N-P-K-Ca-Mg ranges already implied by the existing Strik & Bryla 2015 and Strik/Clark/Finn 2012 citations. Table 7 gives current recommended N fertilization rates (30-50 lb N/acre planting year, 50-80 lb N/acre established plantings for floricane-fruiting blackberry) — consistent with, not conflicting with, the 55 kg/ha (≈49 lb/acre) spring N rate already used as this row's P:N/K:N ratio source. Per Rule 8, none of this leaf-tissue/soil-test data is converted to a feed-ppm value; kept as real corroboration only.

D'Imperio, Montesano, Renna, Parente, Logrieco & Serio (2019), Agronomy 9(10):627 — Hydroponic Production of Reduced-Potassium Swiss Chard and Spinach

(CNR Institute of Sciences of Food Production, Italy; real, peer-reviewed, species-exact floating-hydroponic trial on baby-leaf Swiss chard (Beta vulgaris ssp. vulgaris) AND spinach side by side, testing a reduced-potassium nutrient solution against the control (K200) described as "the concentration usually used for growing baby leaf vegetables in a floating hydroponic system." The K200 control recipe is directly stated: N 140 ppm (NO3-N:NH4-N 80:20), P 50, K 200, Ca 100, Mg 40, S 102 ppm, pH 5.5–6.0. PROMOTES Swiss Chard's NPK to white/verified at **140-50-200 ppm**, replacing the prior generic, mismarked placeholder (200-41-280 ppm) shared with Cabbage/Kale/Mustard Greens (see the Spinach citation above for that placeholder's origin) — this is a genuinely species-exact, directly-stated recipe. pH also promoted to white/verified (5.5–6.0). EC is not directly stated in this paper — see the Currey/Yost/Sporer citation below for that. Spinach's own already-verified NPK (Cornell handbook, 125-31-215) is corroborated in passing — this paper's spinach K200 control (140-50-200) is a real, different but plausible figure for spinach too, not applied since Spinach already has a dedicated, more specific verified source.

do Moraes Gatti, da Silva Barata, Silva, da Cunha, de Oliveira, de Oliveira & Silva (2023), AgriEngineering 5(1):623-630 — Influence of Calcium on the Development of Corn Plants Grown in Hydroponics

Real, peer-reviewed, genus-exact (Zea mays, hybrid Yeldgard VT Pro) greenhouse hydroponic trial (UFRA/UFV/UFMS, Brazil), testing calcium omission (0 mg/L), a complete nutrient solution (200 mg Ca/L), and calcium excess (600 mg/L). Table 1 gives the complete stock-solution recipe directly (mol/L stocks, mL/L dosing) for the "Complete Solution" (200 mg Ca/L) treatment: KH2PO4 1 mL/L, KNO3 5 mL/L, Ca(NO3)2·4H2O 5 mL/L, MgSO4·7H2O 2 mL/L (all from 1M stocks), plus micronutrients and Fe-EDTA. Computed directly from these stock doses: N210-P31-K234 ppm, Ca 200 (exactly matching the paper's own stated "200 mg Ca L⁻¹" label — confirms the conversion), Mg 49, S 64 — essentially the classic Hoagland & Arnon recipe, and near-identical to several other verified rows in this file (e.g. Basil's 210-31-234). pH held 5.5–6.5. Real outcome-validated finding: this Complete Solution treatment gave the best root and shoot dry mass of the three treatments (20.90g root / 22.22g shoot vs. Ca-omission's 4.66g / 15.81g), confirming this recipe as a genuinely well-performing target for corn, not just an incidental control. PROMOTES Sweet Corn's NPK to white/verified at 210-31-234 ppm, replacing the prior all-equal, evidence-free placeholder (103-103-103 ppm) — a clear #3/#4-type upgrade (Corrective Lesson numbering). EC/pH remain as previously sourced; this paper's own EC value isn't separately stated (only the pH-monitoring range, 5.5–6.5, which itself corroborates this row's existing pH figure).

Currey, Yost & Sporer (2021), Greenhouse Product News — Fertilizing Specialty Leafy Greens (trade summary of Yost's Iowa State University M.S. thesis research)

Real, species-exact, NFT/DFT hydroponic finishing-stage trial (Iowa State University Dept. of Horticulture) on arugula, kale, pak choi, AND Swiss chard grown together — authored directly by the researchers who ran the underlying thesis study, reporting their own findings in a trade-journal summary (same standing as other GPN-style research summaries already used in this file). States plainly: "kale and Swiss chard should be provided with nutrient maintained at >1.0 mS·cm⁻¹ or ~2.0 mS·cm⁻¹ to maximize yield and quality" during the finishing stage — while arugula and pak choi have lower EC requirements. PROMOTES Swiss Chard's EC to white/verified, keeping the existing displayed range (1.5–2.5 mS/cm, which already brackets this real recommendation) rather than narrowing it, since the source's own phrasing (">1.0 ... or ~2.0") is not a single precise value. Replaces the prior orange/derived flag. No new NPK or pH data given in this summary — both fields already resolved via the D'Imperio citation above.

Dr Green Thumbs — Hydroponic Strawberry Nutrients Guide 2025 Duan, Yang, Wei, Yang, Fan, Wu, Lyu & Li (2023), Foods 12(12):2318 — Effects of Different Nitrogen Forms on Blackberry Fruit Quality

Real, species-exact blackberry trial (Nanjing Forestry University/Jiangsu Academy of Sciences, China). Applied different N fertilizer forms during the critical growth period and tested harvest timing — NH4+-N significantly improved fruit size, firmness, color, and accumulation of soluble solids, sugars, anthocyanin, ellagic acid, and vitamin C, while NO3--N fruit accumulated more flavonoids/organic acids and had higher antioxidant capacity; fruit size/firmness/color declined over the harvest window while total antioxidant capacity increased. Overall recommends NH4+-N for fruit appearance/taste/nutrition, with early harvest for appearance and later harvest for antioxidant content. Qualitative N-form finding only — no N-P-K ppm, EC, or pH target given anywhere in the paper. Not usable as a number source; logged as real corroboration that blackberry responds distinctly to N form, consistent with the companion Plants 2023 paper below.

Duan, Yang, Yang, Wei, Che, Wu, Lyu & Li (2023), Plants 12(7):1480 — Physiological and Morphological Responses of Blackberry Seedlings to Different Nitrogen Forms

Real, species-exact ('Ningzhi 4') potted blackberry seedling trial, same research group as the Foods 2023 paper above. Compared no-N (CK), NO3--N, NH4+-N, and urea as sole N sources: NH4+-N and urea gave significantly greater plant height, biomass, SPAD, photosynthetic rate, and root growth than NO3--N, which specifically inhibited root growth and increased oxidative-stress markers. Directly measures the CULTIVATION SUBSTRATE's resulting EC and pH under each treatment (not a set target, an outcome): NH4+-N gave substrate pH 4.45 (lowest) and EC 1.83 mS/cm (highest, 1.89x the NO3--N treatment's EC); no N-P-K ppm composition is disclosed for the base nutrient solution used to prepare treatments. Since this is a measured rhizosphere outcome under single-N-form conditions rather than a grower-set multi-nutrient feeding target, it does NOT override this row's existing pH 5.5-6.5 or EC 1.5-2.2 ranges — logged as real, species-exact context suggesting blackberry may tolerate/favor a more acidic root-zone pH and higher EC than currently displayed when fed predominantly as NH4+, worth revisiting if a full staged NH4-based recipe is ever found.

e-GRO Edible Alert, Vol. 4 No. 4 (Raudales & McAvoy, University of Connecticut, in cooperation with Cornell, Penn State, Ohio State, Michigan State, NC State, Purdue, and other land-grant extension programs) — "K is for Cucumbers"

: cucumber-specific hydroponic nutrient range 160–210N, 40–60P, 200–350K, 325–370Ca, 120–140S, 60–75Mg, 1–2Fe ppm, K:N ratio 1.8:1–2.1:1, EC 1.5–3.0 dS/m (seasonally 1.5–3.5) — basis for the derived/orange tier on Cucumber's Veg and Flower NPK

EarthOne — How to Grow Centella asiatica (Gotu Kola) Effect of Nutrient Concentration and pH on Growth and Nutrient Removal Efficiency of Duckweed (Lemna minor)

(peak growth rate observed at pH 7 — basis for Duckweed's refined pH range)

Effect of Nutrient Solution Concentration on Quality of Radish (Raphanus sativus L.) Grown on a Floating System

(real floating-system trial, cvs. 'Girox' and 'Suprella'; full-strength fertilizer recipe explicitly stated: Ca(NO3)2 723 mg/L, KH2PO4 205 mg/L, K2SO4 274 mg/L, KNO3 152 mg/L, Mg(NO3)2 384 mg/L, NH4NO3 40 mg/L, FeEDTA 30 mg/L — computed to 231N-47P-241K ppm elemental — basis for Radish's verified NPK)

Egilla (2009), Proceedings of the International Plant Nutrition Colloquium XVI, UC Davis eScholarship — Yield and Mineral Element Concentration of Beetroot in Response to Nutrient Source in Hydroponic Solution

(real NFT hydroponic trial, beetroot cv. Bull's Blood; two real commercial fertilizers compared — All-Purpose Hydroponic Nutrient 9-4-15 at 108 ppm N (treatment N1Ca1, computes to 108N-21P-149K ppm) vs. Peters Excel-CAL-MAG 15-5-15 at 200 ppm N (treatment N2Ca2, computes to 200N-29P-166K ppm) — N2Ca2 gave significantly higher root fresh weight and adequate Ca/B levels, while N1Ca1 was Ca-deficient; EC 1.67 (N2Ca2) vs. 1.73 (N1Ca1), pH 6.72 (N2Ca2) vs. 6.42 (N1Ca1) — basis for Beet's verified NPK and EC, using the better-performing N2Ca2 treatment; the same underlying study also appears as Egilla, Journal of Plant Nutrition (Lincoln University))

Šic Žlabur, Radman, Opačić, Dujmović, Brkić Bubola & Voća (2023), Plants 12(11):2098 — Alfalfa, Cabbage, Beet and Fennel Microgreens in Floating Hydroponics: Perspective Nutritious Food?

Real, complete, directly-stated-in-mg/L (=ppm) "Tesi" nutrient solution — University of Zagreb, floating hydroponic system — used successfully (real yield/quality outcomes reported) across FOUR species grown side by side: alfalfa, red cabbage, yellow beet, and fennel microgreens. Recipe: 784.5 KNO3 + 272.2 KH2PO4 + 20.9 K2SO4 + 972.5 Ca(NO3)2·4H2O + 246.3 MgSO4·7H2O + 28.0 NH4NO3 mg/L, converting to approximately N234-P62-K391-Ca165-Mg24-S36 ppm; target EC 2.3 mS/cm, target pH 5.5–5.8 (measured average drifted to 6.43 in practice). FLAGGED, NOT APPLIED to Cabbage or Beet's displayed NPK: this is a real, one-recipe-for-four-species formula, not a crop-optimized trial — Cabbage's current figure (Furlani 1999, 198-39-183) came from a study where concentration was the actual independent variable tested FOR red cabbage specifically, which is stronger species-targeted evidence than a shared multi-crop formula, even though Tesi's numbers are equally real and directly stated. Beet currently uses the Di Gioia et al. 2023 17-species shared-solution figure (105-16-117) — Tesi disagrees with that too, on the same "shared formula, not crop-optimized" footing on both sides. Kept as a real, logged, two-way conflict for both Cabbage and Beet; not adopted absent a crop-dedicated concentration-optimization trial for either.

Farmtek Australia — NPK Fertilizers for Strawberries by Growth Stage Febriantara, Sasmita & Irawati (2018), Agrivet: Jurnal Prodi Agroteknologi UPN "Veteran" Yogyakarta 24(2) — The Response on Growth and Yield of Okra (Abelmoschus esculentus L. Moench) Plants Using Substrate Hydroponic System in Various EC Value of Nutrition Solutions and Types of Planting Media

Real, genus-exact (Abelmoschus esculentus) substrate-hydroponic split-plot trial (Yogyakarta, Indonesia), testing EC 1.5/2.0/2.5 mS/cm crossed with three planting media (husk charcoal, sand, husk charcoal+cocopeat). EC significantly affected every measured growth and yield parameter (plant height, leaf area, root volume, flowering age, stem diameter, fruit yield and weight); EC 2.0 mS/cm gave the best overall results of the three levels tested, with husk charcoal the best-performing media. No N-P-K breakdown given — EC-only optimization study. Independently corroborated by a separate real Brazilian NFT trial (UFCG/UFC, already cited elsewhere in this file) which found okra salinity stress began above EC 2.1 dS/m — the two real, independent, genus-exact sources converge tightly on EC ≈2.0 as okra's real target, consistent with and now the basis for Okra's existing EC range in this calculator (2.0–2.4), upgrading it from a generic-Hoagland-baseline classification to a genuine crop-specific corroboration. Okra's NPK remains the unverified ratio placeholder, since neither source gives an NPK figure.

Frontiers in Plant Science (2018) — Production of Low-Potassium Content Melon Through Hydroponic Nutrient Management

(states the standard 'Enshi' solution recommended for melon in Japan: EC 1.32 mS/cm, pH 6.93, citing Hori 1966)

Frontiers in Plant Science (Moosavi-Nezhad & Meng, 2025) — A Calcium-Mobilizing Biostimulant Provides Tipburn Control Comparable to Vertical Airflow Fans in Greenhouse Hydroponic Lettuce 'Rex'

(University of Delaware/NC State; deep-water-culture nutrient solution: 125N-18P-138K ppm, EC 1.2–1.4, pH 5.7–5.9)

Frescura, Boligon, Barbosa, De Souza, Lerner, Laughinghouse, Da Silva, Andriolo, Lopes & Tedesco (2018), Journal of Plant Nutrition 41(10):1293-1302 — Nutrient Solution Concentration and Collection Time in Phytomass Production, Content, Yield and Chemical Composition of Essential Oil of Rosemary

Real, peer-reviewed, species-exact, genuinely soilless/hydroponic (sand-filled pots, drip-fertigated) Rosemary trial (UFSM, Brazil) directly tests 5 real EC levels (1, 2, 3, 4, and 5 dS/m), with two harvest timings (100 and 160 days after planting). Real, outcome-validated findings: essential-oil CONTENT was significantly higher at EC 2, 3, 4, and 5 dS/m vs. the EC-1 control (peak 2.94% at EC 3, quadratic fit), but dry-matter phytomass declined linearly and significantly from EC 3 onward, and essential-oil YIELD per plant (content × biomass) was only significantly reduced at EC 5. The paper's own stated conclusion: "concentrations of nutrient solution greater than 2 dS.m⁻¹ are not indicated" for industrial rosemary oil production, since EC 3+ sacrifices phytomass for little further oil-content gain. Basis for Rosemary's EC, verified at 2.0 dS/m (the paper's own recommended ceiling, balancing oil content against yield loss) — a genuine species-exact, direct EC-optimization trial. Chemical composition of the essential oil itself was NOT significantly affected by EC (only by collection time) — not applicable to this calculator's fields regardless.

Furlani (1998), IAC Boletim Técnico 168 — Instruções para o Cultivo de Hortaliças de Folhas pela Técnica de Hidroponia NFT

(general leafy-vegetable pH target 5.5–6.5, cited via Lira et al. 2018 watercress study — conflicts with the QP Seedlings figure used for Watercress)

Furlani, Silveira, Bolonhezi & Faquin (1999), IAC Boletim Técnico 180 — Cultivo Hidropônico de Plantas

Real, foundational, widely-cited Brazilian technical bulletin (Instituto Agronômico de Campinas) — described elsewhere as "the canonical Brazilian formulation, reference for 95% of commercial leafy-vegetable hydroponic operations in Brazil." Confirmed via multiple independent academic citations (Steidle Neto et al. 2005, Eng. Agríc.; several other Brazilian NFT papers) to recommend EC 1.0–1.2 dS/m during the seedling/transplant phase and 1.4–1.6 dS/m during the production phase, for leafy vegetables including watercress, lettuce, escarole/endive, green onion, chicory, arugula, and parsley. ALSO basis for Tarragon's verified EC: a dedicated real hydroponic concentration-response trial on tarragon specifically (Artemisia dracunculus, ResearchGate publication 366639982, testing 50/75/100/125% of this same Furlani solution) found the 100% strength gave the best overall performance for most characteristics measured, with concentrations up to 119–125% also satisfactory for essential-oil/extract production — confirming the production-phase EC range (1.4–1.6 dS/m) as a real, validated target for this crop specifically, not just a generic leafy-vegetable default. Applied as 1.4–2.0 dS/m (production-phase range extended slightly to reflect the trial's finding that up to ~125% strength also performed well) — kept at the orange/derived tier rather than promoted to white, since the EC figure itself comes from the generic Furlani standard rather than a tarragon-specific measured EC reading; NPK and pH remain separately white, sourced to the existing Haifa-derived citation that already covers Tarragon and Chives together. Replaces the prior unverified QP Seedlings placeholder EC.

Gage & Allen (2021), ADAS Boxworth / Agriculture & Horticulture Development Board — A Review of Nutrient Requirements of Blackcurrant in the UK

Real, recent, genus-exact (Ribes nigrum) industry desk-study review, including a UK grower survey (11 respondents, 668 ha). Gives real soil application rates (current RB209 guidance 70–160 kg N/ha depending on soil/cultivar; growers surveyed averaged 112 kg N/ha; 40–250 kg/ha P2O5 and K2O depending on soil index) and, more usefully, Table 7's example FERTIGATION program by growth stage (kg/ha applied per week): pre-flowering 6N-2P2O5-6K2O-0.7MgO/week, flowering/fruiting 8N-0P2O5-16K2O-0MgO/week, post-harvest 6N-2P2O5-6K2O-0.7MgO/week — a genuine staged feeding pattern (K rising sharply and P/Mg dropping to zero during flowering/fruiting) closely matching the K-rises-for-fruit-set pattern already used for many other crops in this calculator. NOT converted to a ppm/EC figure: these are field-applied kg/ha rates via drip fertigation into soil, not a closed-loop hydroponic solution concentration, and the source itself states "there is also a gap in our knowledge of optimal feeding techniques such as feed composition, EC/pH at application" for blackcurrant specifically — confirming even the source's own authors don't have a hydroponic-equivalent concentration to offer. Kept as the strongest available real, genus-exact, staged corroborating context found for Currants; the calculator's existing Currants NPK figure remains the generic unsupported ratio placeholder. RE-CONFIRMED in a later session's audit of blue-tier (Howhydroponics-only) cells: a fresh multi-angle search (English academic databases plus German-language commercial/extension sources, since blackcurrant is a much larger commercial crop in continental Europe than the US/UK) found no genuine hydroponic-specific EC or pH trial for Ribes nigrum or Ribes rubrum anywhere — every result was either food-science/phytochemistry research, soil-fertilizer guidance, or generic hydroponics consumer content with no crop-specific data. Currants' EC and pH remain blue/Howhydroponics-sourced; this is a confirmed, exhausted dead end, not an oversight.

Garden Vivid — 8 Essential Nutrients for Thriving Hydroponic Strawberries Gondim, Puiatti, Finger & Cecon (2018), Pesquisa Agropecuária Tropical 48(2):83-89 — Artificial Shading Promotes Growth of Taro Plants

(UFV, Brazil; real field-grown, species-exact 'Japanese' taro (Colocasia esculenta) trial — split-plot design, 4 shading levels (full sun, 18%, 30%, 50%) x 4 timing periods over a 9-month cycle, sampled at 8 timepoints; soil-grown, no fertilizer applied at all ("There was no addition of fertilizer or any kind of chemical control"), so this is NOT usable for NPK/EC/pH per Rule 8 — it is, however, a real, direct, species-specific test of LIGHT/shading tolerance, which this calculator's existing Taro row had never had a dedicated source for despite displaying "Partial Shade." Findings: shading consistently increased leaf area, specific leaf area, and leaf/dry-mass partitioning versus full sun at every shading level tested, with no shading level showing inferior growth to full sun — taro tolerates and structurally favors shade over open full-sun cultivation, with 18% shading giving the largest leaf-area expansion specifically. Basis for upgrading Taro's Light field from blue (Howhydroponics-only) to white/verified; Taro's NPK/EC/pH remain unchanged and still blue/unsourced, since this paper does not address fertility at all.

González-Jiménez, Castillo-González, García-Mateos, Valdez-Aguilar, Ybarra-Moncada & Avitia-García (2020), Revista Fitotecnia Mexicana 43(3):299-306 — Response of Blackberry (Rubus spp.) cv. 'Tupy' to Salinity

(Universidad Autónoma Chapingo, Mexico; real, species/cultivar-exact ('Tupy') greenhouse trial, plants in 19L pots with tezontle substrate, open hydroponic system, testing 6 salinity levels via increasing EC — 2.0 (control), 2.2, 2.4, 2.6, 2.8, 3.0 dS/m. Table 1 gives the complete stated ion composition (mmol/L) for every treatment; the control (2.0 dS/m, pH 6.0) converts to approximately N227-P55-K289-Ca174-Mg25-S15 ppm. The control was also the best-performing treatment — yield, plant dry weight, and photosynthetic pigments all declined significantly starting at 2.4 dS/m, with a 60% yield loss by 3.0 dS/m — so this is a real, directly-stated, best-outcome hydroponic-adjacent recipe. FLAGGED, NOT APPLIED (per Fred's explicit judgment): the resulting N and K figures (227 and 289 ppm) run roughly 5x and 5-6x higher than this row's current derived figures (41-45 N, 49-54 K), and this is presently the ONLY complete hydroponic-adjacent N-P-K-Ca-Mg-S-EC-pH source for Blackberry — a single source at this much of a departure from the existing derivation is too large a jump to adopt without a second, independent corroborating hydroponic trial landing in the same range. Kept as a real, logged candidate; revisit if a corroborating source is found. Notably, this recipe's P and K figures (55 and 289) are nearly identical to the HydroBuddy-default recipe already logged against Raspberry (55 and 289 exactly) — see the Klaros Tarım/HydroBuddy entry — an interesting cross-genus convergence worth keeping in mind if either row's NPK is revisited, though it may simply reflect both sources drawing on a generic "cane fruit" template rather than validated species-specific optimization.

Green Ridge Hydroponics — Electrical Conductivity & pH Values for Hydroponic Vegetables Greenhouse Plant Production Journal (Soufi et al., 2025) — Effects of Different Nitrogen Sources and Sodium Bicarbonate on Growth and Nutrient Uptake in Two Garlic Genotypes: A Hydroponic Study

(Vali-e-Asr University of Rafsanjan; used Hoagland solution as base — basis for Garlic's derived EC/pH)

Haber, Luz, Dóro, Duarte, Oliveira & Pirolla (2006), Bioscience Journal — Cultivo Hidropônico de Manjerona em Diferentes Concentrações de Solução Nutritiva

Real, peer-reviewed, species-exact (Origanum majorana) NFT trial (Federal University of Uberlândia, Brazil) testing four concentrations (50/75/100/125%) of the Furlani et al. 1999 base solution on marjoram, in a subdivided-plot design also varying plant position along the channel. Found NO significant difference in height, leaf/bud count, or fresh/dry mass across any of the four concentrations OR channel positions — concluding marjoram can be grown at the most dilute 50% strength without yield loss, attributed to the crop's small stature and low leaf area relative to lettuce (the species the base solution was originally developed for). pH was maintained 5.5–6.5; EC was managed via a threshold-replacement protocol (full solution change whenever EC dropped 0.25 mS/cm from its starting point) rather than a single stated target. Real, genus/species-exact corroboration that marjoram's nutrient demand is modest — broadly consistent with, but not more specific than, Marjoram's existing verified Na/Lee/Park figure (which is a directly-stated complete composition, a stronger source). Not applied to override the displayed NPK — this paper never restates the Furlani base recipe's own ppm composition (a Corrective-Lesson-#6 situation, same as the Karantzi banana paper), only the percentage of it used.

Haifa Group — Fertilization of Tarragon & Chives

(gives direct irrigation-water concentrations in ppm by season — Establishment stage 100-110N/70-90P2O5/100-120K2O/110-140CaO/60-75MgO ppm, with Autumn/Winter/Spring variants ranging 90-150N/50-100P2O5/100-180K2O ppm, pH 5.8-6.2 throughout; unlike Haifa's Garlic, Asparagus, and Mint pages, this document never states a growing medium or soil type and doses directly in ppm rather than kg/ha, the convention used throughout this calculator's confirmed soil-fertigation Haifa sources — treated as substrate/container-fertigation eligible on that basis; computes to 105N-35P-91K ppm at the establishment-stage midpoint — basis for Chives' and Tarragon's verified NPK and pH; EC remains separately orange/derived-sourced since this page gives no EC figure)

Haifa Group — Grow Better Blackberries with Haifa Products

Real, dedicated, industry-published blackberry crop guide. Gives leaf-tissue sufficiency standards (normal ranges: N 3-4%, P 0.3-0.5%, K 2.5-3.5%, Ca 0.5-1%, Mg 0.3-0.4%, S 0.3-0.6%, plus Fe/Mn/Zn/Cu/B ppm ranges) consistent with the Strik/Bryla and PNW-780 leaf-tissue standards already used elsewhere in this row's derivation. Also gives a K-application-by-growth-stage table (Leaf emergence 15% → Flowering 20% → Fruit set 25% → Fruit growth 25% → Fruit maturation 15% of total seasonal K2O) and a total-nutrient-requirement-by-yield table (kg/ha N-P-K-Ca-Mg-S and g/ha micros, scaling with estimated yield 5-20 ton/ha) — both real but expressed as season totals/percentages or per-hectare removal rates, not feed-solution ppm, so not directly convertible per Rule 8. Separately cites a staged N/P/K SEASON-DEMAND PERCENTAGE table (Oseguera & Sánchez 2015, Mexico, blackberry var. 'Tupi'/'Tupy'): Vegetative-pre-defoliation N18/P12/K16%, After-defoliation-sprouting N23/P22/K24%, Sprouting-flowering N4/P24/K26%, Flowering-fructification N55/P42/K34% (each column sums to 100%). FLAGGED, NOT APPLIED: this shape disagrees with the current Veg/Bloom/Fruit derivation's near-flat N profile (42/45/41 ppm) — Oseguera & Sánchez's percentages would imply N should be front-loaded and then spike sharply at fructification rather than staying flat, and P/K should dip during the Bloom-equivalent (sprouting-flowering) stage rather than rising slightly as currently shown. A naive rescaling of the current ppm figures by these percentages was tested and rejected (it produces an implausible ~5 ppm N at Bloom) — percentage-of-seasonal-uptake is not equivalent to feed concentration without an uptake-efficiency/duration assumption this file does not make (Rule 8). Kept as a real, staged, industry-sourced shape disagreement worth a dedicated staged hydroponic-blackberry trial to resolve; not used to alter displayed NPK. The current Bloom-stage N figure (45 ppm, nearly identical to Veg and Fruit) is the single value this source disagrees with most sharply in direction and is the best candidate for a future dedicated citation search.

Haifa Group — Growing Beans with Haifa Fertilizers

(industry source, approved per the supplier-survey process; "Soilless fertilization of beans" section gives a real rockwool nutrient solution table — EC 1.7 mS/cm, N-NH4 13.8 + N-NO3 167.9 ppm, K 215.1 ppm, H2PO4 121.3 ppm, Ca 130.3 ppm, Mg 30.4 ppm, plus micronutrients — sourced by Haifa to Straver 1994 and de Kreij/Sonneveld/Warmenhoven/Straver 1992, Dutch glasshouse standards. Only this soilless section was used; the rest of the page is field/soil fertigation guidance, out of scope per the hydroponic-only constraint on industry sources — basis for Beans' Veg-stage industry-sourced NPK and EC)

Haifa Group — Nutritional Recommendations for Pepper

(full technical guide, Section 3.2 "Soilless-grown pepper"; Table 22, Florida/USA example, composted pine bark substrate: Transplant-to-first-flower 100N-50P-120K-100Ca-40Mg-50S ppm, After-first-flower 130N-50P-200K-150Ca-50Mg-60S ppm; Table 20, Holland example, rockwool: N-NH4 17.3 + N-NO3 216.9 = 234N-39P-254K ppm, Ca 190.5, Mg 36.5, S 55.5, EC 2.2 dS/m — basis for Peppers' verified Veg/Flower NPK (Florida pine-bark stages) and Fruit NPK/EC (Holland rockwool); both sourced to the same Straver/de Kreij-Sonneveld-Warmenhoven-Straver Dutch glasshouse lineage used throughout this calculator)

Hasselt University / SCK CEN (Van Dyck et al.) — Effects of Environmental Parameters on Lemna minor Growth Havlin, Fernandez & McWhirt (2023), NC State Extension AG-697 — Southeast Regional Caneberry Production Guide: Fertility Management

Real, current multi-state extension guide covering both blackberry and raspberry — field/soil agronomy only. Table 11-1 gives preplant soil-test sufficiency levels (P 20-30, K 100-200, Ca 500-1000, Mg 50-125, S 10-20 ppm) and Table 11-2 leaf-tissue sufficiency ranges (N 2.5-3.5%, P 0.15-0.25%, K 0.9-1.5%, Ca 0.48-1.0%, Mg 0.3-0.45%, S 0.17-0.21%) — consistent with the ranges already corroborated by PNW-780 and Haifa above. Blackberry first-year N rate: 10-25 lb N/acre split-applied; established: 60-80 lb N/acre by year 3, broadly consistent with the existing 55 kg/ha (≈49 lb/acre) spring rate this row's P:N/K:N ratios are built from. Per Rule 8, this leaf-tissue/soil-test data is not converted to feed ppm; kept as corroboration only.

Hazrati et al. (2024), Folia Horticulturae 36(2) — Effect of Different Nutrient Solution Compositions on Yield and Quality of Basil Grown in an NGS® Hydroponic System

DOI 10.2478/fhort-2024-0034. Real, peer-reviewed, species-exact (Ocimum basilicum) NGS® (Nutrient Gutter System) hydroponic trial, full 4-treatment factorial varying N and K levels, with complete N-P-K-Ca-Mg ppm figures directly stated per treatment (e.g. best first-harvest yield at treatment N12P2K6: 168N-62P-234K ppm, Ca 100, Mg 48, EC ~2000–2500 µS/cm, pH 5.5). A genuinely different real recipe from the existing verified Khater et al. 2021 figure (210-31-234) — notably lower N and higher P, though K matches closely (234 in both). The paper also found a real, actionable staging recommendation: yield was best in the first harvest at the higher-N treatment, but the nutrient solution should be diluted for subsequent harvests to avoid salt buildup — a real cut-and-regrow consideration not reflected in this calculator's single-figure display. Kept as a second real, independent, species-exact corroborating source — Basil's displayed NPK/EC/pH remains sourced to Khater et al. 2021, unchanged.

Horticultural Science and Technology (2025, University of Seoul) 43:685-694 — Growth and Quality of Leafy Sweet Potatoes Grown Hydroponically Under Different EC Conditions in a Plant Factory

Real plant-factory-with-artificial-lighting (PFAL) trial, two genus-exact cultivars bred specifically for leaf production ('Tongchaeru', Korea; 'Suioh', Japan) — tested EC 1.0, 2.0, 3.0, and 4.0 dS/m, pH held 6.0–6.5. Nutrient solution formulated per Japan Horticultural Experiment Station recommendations for leafy vegetables, given in full (me/L): NO3 14, NH4 1, P 3, K 6, Ca 8, Mg 4, SO4 4 — converts to roughly 210N-93P-235K ppm, Ca 160, Mg 49. EC 2.0 gave the clearly best result across both cultivars on every growth metric measured (plant height, leaf count, stem diameter, leaf area, shoot/root dry weight); EC 1.0 AND EC 4.0 were both worse, giving a genuine bounded optimum rather than an open-ended "more is better" result. Basis for Sweet Potato's verified NPK, EC, and pH, replacing the prior generic, uncited ratio placeholder (5-10-10). NOTE: this cultivar group is bred for leaf/shoot harvest, not storage-root production — the calculator's existing Sweet Potato row does not distinguish leafy vs. root cultivar types, so this figure is applied as the best available single answer for the row as it exists. See the companion Sakamoto & Suzuki 2020 citation below for a root-type cultivar trial with a broadly similar-shaped recipe, included as corroboration.

Horticultural Science and Technology (Lee, Cui, Lee, Hwang & Chun, 2023, Seoul National University) — Optimization of the Pot Volume and Substrate for Strawberry Cultivation in a Hydroponic System

— fertigated with Yamazaki strawberry nutrient solution at pH 5.2–5.8, EC 0.76–1.14 dS/m — third independent corroboration of Strawberry's Yamazaki-based staged NPK

Horticulture, Environment, and Biotechnology (Springer) — Optimal Levels of N, P, and K for the Cultivation of Single-Stemmed Roses in a Closed Hydroponic System

(growth plateaued above 150N-40P-200K ppm — basis for Rose's verified NPK)

Howard M. Resh — Hydroponic Food Production

(academic horticulture reference, "Nutrient Formulations and Solutions" chapter) — general fruiting-crop macronutrient formulation: 140N-50P-352K-180Ca-50Mg-168S-5Fe ppm — cited as context for Melons' Veg-stage derived NPK note

HydroBuddy (danielfppps) — Open Source Hydroponic Nutrient Solution Calculator HydroHowTo — List of pH & EC Levels for 65+ Hydroponic Vegetables & Herbs Hydroponic Advice — Hydroponic Strawberries Guide Hyjo — pH, EC & PPM Guide for Hydroponics: Essential Nutrient Management Indian Journal of Agricultural Sciences (Singh, Sharma, Gupta, Dilta & Laishram) — Response of Carnation cv Master to Water Soluble Fertilizer Sujala (19:19:19 NPK)

(Dr YS Parmar University of Horticulture and Forestry — best treatment 250 ppm N and K via 19:19:19; SUPERSEDED for NPK (2026-07-12) by Vélez Carvajal et al. 2022's real, directly-stated, staged Vegetative/Production fertigation recipe (see Carnation citation above), now split into two Table 2 rows — Carnation (Veg) 200-30-150 and Carnation (Flower) 150-30-150. This citation remains the basis for Carnation's EC/pH only: EC/pH upgraded to verified since OSU Extension HLA-6722 independently confirms the same 2.0–3.5 EC range with pH 6, falling within this study's 5.5–6.0 pH range — both new Carnation rows retain this EC/pH figure unchanged.)

IntechOpen — Nutrients for Hydroponic Systems in Fruit Crops International Journal of Agricultural and Biological Engineering (Yu, Zheng, Wang, Ji & Zhu, 2023, China Agricultural University) — Adjusting the Nutrient Solution Formula Based on Growth Stages to Promote the Yield and Quality of Strawberry in Greenhouse

— full staged recipe (Table 3) based on the 1982 Yamazaki strawberry formula, modified per stage; increased yield 20–26% over the original — basis for Strawberry's fully verified 3-stage NPK

Iowa State University (Kramer, Currey & Boldt) — pH Optima: Determining the Optimal pH for Hydroponic Herb Production (via Produce Grower) Iqbal, Saleem & Javed (2017), Int J Sci Environ Technol 6:1989-1999 — Effect of Electrical Conductivity (EC) on Growth Performance of Duckweed at Dumpsite Leachate

Real, species-exact (Lemna minor) dedicated EC-optimization trial — genuinely tested EC as the variable across a range (leachate diluted to various strengths), not an incidental reading. Found maximum relative growth rate (fresh-weight basis, 0.176) at EC 1200 µS/cm and maximum frond-number RGR (0.193) at 800 µS/cm, with the overall optimum growth range determined to be EC 600–1400 µS/cm (0.6–1.4 mS/cm) — nutrient/COD removal rates were also maximized in this same range. PROMOTES Duckweed's EC to white/verified at 0.6–1.4 mS/cm (was 0.5–1.0, orange/derived), replacing the weaker prior derivation with this real, dedicated, tested-variable optimization for the same species.

Iranian Journal of Medicinal and Aromatic Plants Research — Effect of Nitrogen Levels on Growth and Essential Oil Content of Hydroponically Grown Sage (Salvia officinalis)

Real, species-exact (Salvia officinalis — the actual species this row represents, not a different Salvia) hydroponic pot trial testing N at 0, 70, 140, and 210 mg/L. Best growth and essential-oil content were obtained at the highest N level tested, 210 mg/L — landing almost exactly on Sage's existing N figure (200 ppm, sourced above from the NC State container-production guide) and independently corroborating it from a genuinely hydroponic, species-exact trial rather than a container/nursery liquid-feed program. P and K were not tested or reported in this trial (N was the sole variable), so per this calculator's standing Rule 5 it cannot be used to complete or replace the existing P/K figures — kept as a real, strong corroborating citation for the N value only. NPK stays orange/derived, unchanged.

ISHS Acta Horticulturae 433 (Argüello, Núñez & Ledesma, 1997) — Bulbing Physiology in Garlic (Allium sativum L.) cv. "Rosado Paraguayo" III. Nutrient Content in Garlic Plants: Its Relation to Growth Dynamics and Bulb Morphogenesis

(Universidad Nacional de Córdoba, Argentina; SOIL-grown garlic, not hydroponic — sampled every 15 days from clove emergence through harvest to track N, P, K, Ca, S content in shoots and bulbs across the full ontogeny — found N and K are the most abundant elements throughout, nutrient demand is low during early sprouting, rises sharply from the start of shoot growth (~60 days after sowing) through early bulb filling, dips briefly during the inductive bulbing stage, then rises again after bulb filling begins — concludes the critical fertilizing period for garlic is "from the start of aerial growth to the beginning of bulb filling," and fertilizing after bulbing (BI≈0.5) does not meaningfully help yield. Not a feeding-concentration source (this is uptake/content data from soil-grown plants, not a hydroponic nutrient solution), so it does NOT supply or change any of Garlic's NPK figures — but it is the clearest evidence in this registry for WHEN garlic nutrient demand peaks during the crop cycle, directly relevant to how this calculator's Veg/Bulb/Mature staging should be timed regardless of which NPK numbers fill each stage)

ISHS — Effect of Different Nutrient Solution EC During Growth Stages on Fruit and Vegetative Characteristics of Strawberry in Hydroponic System ISHS — Effects of Different Nutrient Solutions on Yield, Quality and Nutrient Consumption of Green Beans

(N and K basis for Green Beans' derived NPK)

Islam, Hirai & Kitaya (2008), Journal of Applied Horticulture 10(2):132-136 — Hydroponic Cultivation of Carrots Using Modified Rockwool Blocks

(Osaka Prefecture University, Japan; real hydroponic root-vegetable trial, three carrot cultivars, rockwool blocks with vermiculite-filled rooting holes, sub-irrigated for 90 days — full stated nutrient solution: N 35, P 14, K 59, Ca 23, Mg 10 ppm plus a full micronutrient panel (Fe 0.62, Mn 0.12, B 0.06ppb, Cu 0.02, Zn 0.04, Mo 0.01 ppm). DERIVED for use on Parsnip, NOT Carrot, since this calculator has no separate Carrot row — Parsnip (Pastinaca sativa) and Carrot (Daucus carota) are different genera within the same family (Apiaceae), both root-storage taproot vegetables with broadly similar growth habit, so this is a cross-genus same-family analogy, not a direct species match — kept orange/derived rather than promoted to white given that distinction. No EC value is stated anywhere in this paper. EC/PH UPDATE (later session, dedicated audit of yellow-tier cells): multiple independent real consumer hydroponic-growing guides for carrot (Hydrobuilder Learning Center, Betilife, hydrogrowingsystems.com — checked via fresh search, none academic) converge tightly on EC 1.6–2.0/2.2 mS/cm and pH 6.0–6.5 for hydroponic carrots specifically. Applied to Parsnip via the same established cross-genus carrot analogy used for NPK above — replacing the prior generic, uncredited QP Seedlings EC/pH figures (which were yellow/lowest-tier) with this named, multi-source, real-but-non-academic consensus (now blue/Howhydroponics-equivalent tier, a genuine upgrade in attribution even though not promotable to white). Separately confirms (via a related patent search) that parsnip itself has been successfully grown in a 25-26cm deep inert soilless media bed with sub-surface nutrient solution delivery, producing straight, normally-shaped taproots — real confirmation that parsnip CAN be grown hydroponically given sufficient media depth (most NFT-channel systems, at only 2-4 inches deep, cannot accommodate it), though that patent example gives no nutrient concentration data of its own.

Itagaki et al. (2021), Ozone: Science & Engineering 44(5) — Intermittent Root Flushing with Ozonated Water Promotes Growth of Japanese Mustard Spinach in NFT

(independently states the full-strength "Otsuka house A solution" composition: NO3-N 16.8, NH4-N 1.8, P 5.1, K 8.6, Ca 8.2, Mg 3.0 me/L at EC 1.2 dS/m — not a garlic study itself. RETRACTED USE: this was previously cited as the conversion basis for a secondhand "half-strength Otsuka House A" reconstruction of Naznin et al. 2009/2010's garlic recipe (~130N-79P-168K ppm), used as one half of Garlic\'s Veg-stage blend. The 2009/2010 paper\'s full primary text has now been obtained directly and does not use "half-strength Otsuka House A" language anywhere — it states a different, much lower figure instead (see that citation). The conversion this entry supported has been retracted; kept here only as general background on what "Otsuka House A" refers to, no longer tied to any displayed Garlic figure.)

Jack's Nutrients (JR Peters) — Two-Bag Leafy Greens and Herbs Nutrition Schedule

— states a direct Target EC of 1.1 (Propagation) and 1.75 (Vegetative-Harvest) for this herbs/leafy-greens formula category — basis for Cilantro's EC value (1.75, harvest-stage target), replacing a prior session's mischaracterization of the MDPI study's discrete 0.5–4.0 dS/m experimental treatment levels as if they were a single recommended target range. This is a category-level (herbs in general, not cilantro by name) industry match, so EC stays orange/derived, consistent with NPK and pH on this row.

Journal of Bio-Environment Control (Seoul City University) — Composition of Nutrient Solution for Endive (Cichorium endivia L.) Hydroponics

(explicit endive-specific NO3-N/NH4-N/PO4-P/K/Ca/Mg me/L recipe, basis for Endive's derived NPK)

Journal of Mountain Research (2025) — Impact of Nutrient Electrical Conductivity on Growth, Yield and Quality of Beet Leaf in Hydroponic NFT

(DIBER DRDO, Haldwani, India)

Juárez-Rosete, Aguilar-Castillo, Aburto-González & Alejo-Santiago (2019), Revista Chapingo Serie Horticultura — Biomass Production, Nutritional Requirement of N, P and K, and Concentration of the Nutrient Solution in Oregano Kane, C.D. (2006), M.S. Thesis, Texas Tech University — Influence of Nutrient Solution and Solution pH on Onion Growth and Mineral Content

Real, complete, full-text-obtained (user-supplied excerpt) hydroponic onion (Allium cepa cvs. 'Deep Purple', 'Kinka', 'Purplette') trial, citing Jasoni et al. (2002) for the tested nutrient solutions. Table 1.3 gives three complete, directly-stated recipes in mM: Modified Hoagland's (N 12.0, P 2.00, K 5.98, Ca 3.99, Mg 1.97, S 2.00 → 168N-62P-233K ppm), Modified ½-strength Hoagland's (84-31-117 ppm — exactly half), and a commercial product Hydro-Sol (N 10.7, P 1.55, K 5.37, Ca 3.22, Mg 1.23, S 0.41 → 150-48-209 ppm). REPLACES the prior generic, unsourced 150-31-210 NPK placeholder (that figure was a coincidental near-match to Hydro-Sol's N and P but not its K, S, or Ca — not actually derived from this or any other onion-specific source). Real finding, directly from the thesis's own conclusion: "The half strength Hoagland's solution is the preferred nutrient solution evaluated in this research" for total and edible biomass, DESPITE Hydro-Sol producing onions with the highest mineral content (Mg, K) — the thesis explicitly notes these are competing goals ("the solution that produced the greatest biomass did not produce plant material with the highest mineral content"). Half-strength Hoagland's (84-31-117 ppm) used here as the NPK figure, reflecting the thesis's own stated preference; kept orange/derived since applying "the preferred solution" required a judgment call between three real options rather than a single unambiguous target. EC was not found stated as a target value anywhere in the excerpts available — the prior EC figure (2.0–2.6) was never actually traceable to any source and stays flagged honestly as orange/derived rather than left falsely white.

Kane, Jasoni, Peffley, Thompson, Green, Pare & Tissue (2006), Journal of Plant Nutrition 29(2):375-390 — Nutrient Solution and Solution pH Influences on Onion Growth and Mineral Content

(Texas Tech University; the published journal version of the Kane thesis above — same lab, same three nutrient solutions and near-identical Table 1 composition (Modified Hoagland's N 12.0/P 2.0/K 6.0/Ca 4.0/Mg 2.0/S 2.0 mM; half-strength exactly half; Hydro-Sol N 10.7/P 1.6/K 5.4/Ca 3.2/Mg 1.2/S 0.4 mM — matching the thesis's figures to within rounding). What this published version adds that the thesis excerpt didn't have: a directly-stated, tested pH comparison. Both pH 5.8 and 6.5 were tested for all three solutions (a 3×2 factorial), and total biomass, edible biomass, and shoot mass were all significantly greater at pH 6.5 than 5.8. The paper's own conclusion states the half-strength Hoagland's solution AT pH 6.5 was "the preferred nutrient solution evaluated in this research" — the same solution already used above for NPK, now with a real, direct, outcome-backed pH value attached to it. PROMOTES Onion's pH from the prior derived range (6.0–6.5) to a single white/verified value: 6.5. NPK stays as already set above (still orange, per that citation's own reasoning). EC was monitored for pH but not reported as a target value in this paper either (only initial pre-adjustment pH readings of 5.0/4.4/4.2 before correction to the tested levels) — Onion's EC remains orange/derived.

Kalaivanan, Selvakumar & Shankara Hebbar (2020), Indian Journal of Horticulture 77(3):496-502 — Effects of Varying N, P and K Concentrations on Growth, Biomass, Yield and Nutritional Quality of Zucchini Squash Grown Under Open and Polyhouse Soilless Culture

Real, peer-reviewed, species-exact (Cucurbita pepo hybrid 'Champion'), genuinely soilless (Arka Fermented Cocopeat substrate, both open-field and polyhouse) zucchini trial (ICAR-Indian Institute of Horticultural Research, Bengaluru). Four real, directly-stated N-P-K treatments: T1 128-11-120, T2 147-13-155, T3 168-16-189, T4 185-19-224 ppm, EC 1.2–1.6 dS/m across treatments. T4 (highest concentration) gave the maximum plant height, leaf count, and total dry biomass — promoted to Squash, Summer's Veg stage, white/verified, replacing the prior orange/derived Cucumber-extrapolated figure. T3 gave the best fruit weight/length/girth/yield — a real, outcome-validated alternative that conflicts with the Fruit stage's existing Pacheco et al. 2023 figure (209-31-425); logged as an open 2-way conflict there, not resolved. Also reports full fruit tissue macro/micronutrient content by treatment (Table 5) and confirms soilless culture out-yields soil culture for zucchini (65.8 vs 46.3 t/ha).

Kano, Kitazawa, Suzuki, Widiastuti, Odani, Zhou, Chinta, Eguchi, Shinohara & Sato (2021), Agronomy 11(3):491 — Effects of Organic Fertilizer on Bok Choy Growth and Quality in Hydroponic Cultures Xie & Yu (2013), Chinese Patent CN102992835A — Banana Water Culture Nutrient Solution Formula

Real, complete, species-exact hydroponic (water-culture) banana nutrient solution, filed as a Chinese patent (application CN201110291054, published 2013-03-27) rather than a peer-reviewed paper or an approved-industry-list source — a source-category question this file's standing rules don't explicitly cover, but Fred has explicitly directed its use (2026-07-11). PROMOTED TO WHITE/VERIFIED on both NPK and pH: the values are a direct, unaltered quote of this single dedicated source's own stated banana-specific formula, not an extrapolation from a related crop or general principle (the definition this file reserves for the orange/derived tier) — the admissibility question (is a patent an acceptable source category at all) is separate from and doesn't change the directness of the data itself. States the invention was developed specifically because generic vegetable/flower nutrient formulas don't supply enough potassium for banana, a "potassium-loving" crop, and reports that banana seedlings adapted to water culture within a week and grew strong new roots and shoots under this formula. FULL STATED FORMULA (pH 6.0–6.2): N 130–150 ppm, P 30–40 ppm, K 300–360 ppm, Ca 120–150 ppm, Mg 30–40 ppm, S 45–55 ppm, B 0.3–0.5 ppm, Zn 0.3–0.5 ppm, Cu 0.03–0.05 ppm, Fe 4.0–6.0 ppm, Mn 0.6–1.0 ppm, Mo 0.010–0.020 ppm. Salt sources given directly: Ca(NO3)2·4H2O, NH4NO3, KNO3, KH2PO4, KCl, K2SO4, MgSO4·7H2O, H3BO3, ZnSO4·7H2O, CuSO4·5H2O, FeSO4·7H2O, MnSO4·H2O, (NH4)6Mo7O24·4H2O, Na2EDTA — prepared as two 150× concentrated stock solutions (macros in stock A, trace elements in stock B), diluted to volume, pH corrected to 6.0–6.2 with dilute HCl/NaOH. REPLACES Banana's prior unevidenced 103-103-103 NPK placeholder — per Fred's explicit instruction (2026-07-11) — with the midpoint of this formula's stated ranges: 140-35-330 ppm. ALSO REPLACES Banana's prior pH (5.5–6.5, from the OSU Extension Table 2 general reference) with this patent's directly-stated, narrower 6.0–6.2 range. Banana's EC (1.8–2.2, OSU Extension-sourced, unchanged) remains a separate, still-orange-eligible-if-ever-questioned field, since this patent states no EC/TDS reading. Ca/Mg/S/micronutrient figures are not displayed anywhere in this calculator's UI (which only tracks N-P-K/EC/pH per crop) but are preserved here in full for the record in case a future session adds secondary-nutrient tracking or needs to reconstruct the complete recipe.

Karantzi, Papadakis, Psychoyou & Ioannou (2016), Acta Horticulturae 1139:399-403 — Nutrient Status of the Banana Cultivar 'FHIA-01' as Affected by Boron Excess

Real, peer-reviewed, species-exact (Musa acuminata 'FHIA-01') hydroponic trial (Agricultural University of Athens), inert sand:perlite (1:2) substrate, fertigated with full-strength Hoagland's nutrient solution containing either 25 μM (control) or 400 μM boron. The paper's actual purpose is boron-toxicity tissue mineral analysis (K, Ca, Mg, Fe, Mn, Zn, Cl, Na measured in leaves/pseudostem/root, not a feed-solution ppm target) — real findings include boron accumulating most heavily in leaves (phloem-immobile in banana) and B excess significantly raising leaf/pseudostem K and Mn while lowering leaf Ca and Mg. NOT used to change Banana's displayed NPK: the paper names "full-strength Hoagland's" as its base recipe but never restates that recipe's own N-P-K composition in ppm — only Boron concentration is stated as the tested variable — so applying it here would require pulling in a separate, unconfirmed source (the original Hoagland & Arnon 1950 formulation) rather than a figure this paper itself states, which this calculator's standing rules don't permit. Logged as real, on-topic, species-exact corroboration that standard Hoagland's is a genuine working recipe for hydroponic banana, without providing an independently verifiable ppm figure of its own.

Kathi, Laza, Singh, Thompson, Li & Simpson (2023), Frontiers in Plant Science 14:1145992 — Vitamin C Biofortification of Broccoli Microgreens and Resulting Effects on Nutrient Composition

Real, dedicated, peer-reviewed broccoli-microgreen trial (Texas Tech University, Frontiers in Plant Science), full primary text read this session. Base fertilizer was "2-1-6 Floragro (NPK; General Hydroponics, Santa Rosa, California)" supplemented with 0–0.5% ascorbic acid. NOTE (corrected this session, per Fred): this file's standing GH rule disqualifies General Hydroponics' own product literature/site as a claimed-recipe source — it does not disqualify independent, peer-reviewed academic research that happens to use a commercial GH product as one experimental input. Kathi et al. is exactly that: real academic data, not a GH marketing claim, so it is NOT disqualified by that rule. Real, directly-stated EC per treatment (Table 1, µS/cm): control (0% AA, i.e. base fertilizer alone) 408–411 (≈0.41 mS/cm), rising to 2710 at 0.5% AA as KOH was added to buffer pH; pH held 6.0–6.5 throughout via KOH addition. Not applied to Broccoli's displayed EC/pH/NPK for a study-design reason instead: ascorbic acid concentration was the tested independent variable here, not base fertilizer strength — the control treatment's EC (0.41 mS/cm) is real but reflects one specific commercial product's dilution rate, not a concentration this paper set out to optimize, so it's a weaker candidate than the dedicated Palmitessa/Di Gioia concentration-optimization trial already backing this row. Separately, real finding: AA supplementation increased K content and fresh biomass but decreased leaf N, P, Mg, Ca, S, B — a genuine nutrient-antagonism result from a foliar/solution biofortification context, not a baseline feeding trial. Logged as real, usable-in-principle academic corroboration, not GH-disqualified.

Khan, Purohit & Vadsaria (2021), Journal of Plant Nutrition 44(10):1515-1538 — Hydroponics: Current and Future State of the Art in Farming

Broad review of hydroponic history, system types (NFT, ebb-and-flow, drip, DFT, floating raft, aquaponics, aeroponics), components, and global adoption. Full PDF read directly this session. Its Table 2 gives only generic textbook-level concentration RANGES, not crop-specific figures (N 100–200, P 30–50, K 100–200, Ca 200–300, Mg 30–80, S 70–150 ppm) — same genre as the Hoagland/Steiner/Sonneveld generic solutions already excluded from white-tier status per this file's Rule 2. However, the body text DOES cite real tomato-specific EC stress thresholds: Cuartero & Fernandez-Munoz (1998) found tomato water uptake significantly restricted above EC 4–6 dS/m, and Athanasious et al. (2005) found EC ~3.5 dS/m affecting tomato root growth and marketable yield on rockwool. These are real, genuine corroboration that Tomato's existing Fruit-stage EC ceiling (3.5–4.0 dS/m, already white/verified via the Jensen/UA-CEA staged recipe) is correctly placed just below the documented stress threshold, not set too high — kept as supporting context, not used to change the displayed figure since it's a stress threshold rather than a feeding target.

Khater, Bahnasawy, Abass, Morsy, El-Ghobashy, Shaban & Egela (2021), Scientific Reports 11:12754 — Production of Basil (Ocimum basilicum L.) Under Different Soilless Cultures

(Benha University, Egypt; real, species-exact basil trial comparing aeroponic, hydroponic (deep water culture), and peatmoss-slab systems — all THREE systems fed the identical nutrient solution, varying only growing medium, isolating the medium's effect from the recipe's. Recipe directly stated in ppm (not derived): N=210, P=31, K=234, Ca=200, Mg=48, S=64, plus micronutrients, with pH adjusted to 6.5–7.0 and EC to 1.4–1.8 dS/m after salt addition — basis for Basil's verified NPK/EC/pH, replacing the prior generic, unsourced placeholder (150-31-210) that had been shared with Cilantro, Dill, and Parsley with no basil-specific support. Worth noting as context (not used to change the displayed recipe, since all three systems shared it): aeroponic culture significantly outperformed hydroponic and peatmoss on every growth metric measured — shoot length (71.7cm vs 65.7cm vs 62.3cm), root length, fresh/dry shoot and root mass, N/P/K/Ca/Mg uptake, and essential oil content (6.32 vs 4.36 vs 2.66 g/plant) — all at the 7-week flowering-stage harvest. The paper attributes this to aeroponic roots having access to ~100% available oxygen versus submerged or substrate-bound roots, not to any difference in nutrient solution composition.

Klaros Tarım — Nutrition Recipes (Beslenme Programları), "Rivulis Stage Specific Blueberry" entry

Real, industry-published, staged (vegetative/harvest) Blueberry fertigation program from Rivulis (global drip-irrigation/fertigation manufacturer, added to this file's approved Industrial Sources per Fred's instruction, 2026-07-04), republished on Klaros Tarım's nutrition-recipes page (Fred-supplied, 2026-07-04). States pH 4.5–5.5, EC <1.5 dS/m, and a complete staged elemental ppm table: N 100 (veg) / 80 (harvest), P 21.8, K 83 (veg) / 124.5 (harvest), Ca 71.5, Mg 39.2, plus micros (Fe 5, Mn 0.5, Zn 0.05, Cu 0.03, B 0.45, Mo 0.003). This is a real, dedicated, staged industry program — notably more detailed than this row's current single-stage figure (46-16-59 ppm) — but Blueberry is currently a single-row (T2) entry in this calculator, not staged (T1), so directly adopting Rivulis's veg/harvest split would require converting Blueberry into a staged crop, a structural change beyond a simple cell edit. Also, the existing 46-16-59/EC 0.8/pH 4.5 figure is already white/verified from a real, dedicated academic trial (Frías-Ortega et al. 2020) — real-vs-already-verified, so per this file's standing practice this needs Fred's explicit choice rather than an automatic replacement. NOT applied — logged in full as a real, high-quality, staged alternative for Fred's consideration (either as a straight NPK swap within the current single-row format, using e.g. the harvest-stage figures 80N-22P-125K, or as a future T2→T1 staging conversion).

Klaros Tarım — Soilless Blackberry (Turkish: Böğürtlen)

Real, dedicated, industry-published soilless-blackberry guidance (page text supplied directly by Fred, 2026-07-04, since the site is a JS-rendered SPA not independently fetchable). States pH 5.5–6.5 (matching this row's existing pH exactly — real corroboration, though industry-sourced rather than peer-reviewed, so the pH tier stays at industry/purple rather than white) and staged EC: 1.5–1.8 mS/cm during vegetative cane growth, 1.8–2.2 mS/cm during flowering and fruiting. PROMOTES Blackberry's EC from the prior Raspberry-genus extrapolation (which had explicitly no hydroponic blackberry data at all) to these real, dedicated, staged values. Also gives staged N-P-K as FERTILIZER RATIOS, not ppm concentrations (Vegetative/primocane: "Balanced 20-20-20"; Flowering/fruiting/floricane: "High Potassium 15-5-30"; a "double-cropping" technique adding a 30% N spike to trigger a second flowering wave) — these are fertilizer-label ratios, not usable as ppm without a stated dilution/injection rate, so NOT applied to Blackberry's NPK, which remains the existing Strik-based field-derived figure above. Also documents a real commercial fertigation/automation setup (independent drip line per pot, solar-radiation-triggered irrigation, automatic pH/EC dosing, 20–30% drainage target) — system-design detail, not itself a feeding number.

Klaros Tarım — Soilless Blueberry (Turkish: Yaban Mersini)

Real, industry-published soilless-blueberry guidance (page text supplied by Fred, 2026-07-04). States pH 4.8–5.2 and EC 0.8–1.2 mS/cm — real corroboration bracketing this row's existing verified pH (4.5, just below this range) and EC (0.8, at the low end of this range) from the academically-verified Frías-Ortega et al. 2020 source. Also states ammonium-form N is preferred over nitrate for blueberry, and iron should be chelated as EDDHA specifically (to remain plant-available at blueberry's low pH) — real, useful agronomic detail, but not itself a ppm figure, so not applied to any displayed field. Kept as industry corroboration; Blueberry's displayed EC/pH are unchanged (already close to this range and academically sourced).

Kyriacou, El-Nakhel, Pannico, Graziani, Soteriou, Giordano, Palladino, Ritieni, De Pascale & Rouphael (2020), Antioxidants 9(3):252 — Phenolic Constitution, Phytochemical and Macronutrient Content in Three Species of Microgreens as Modulated by Natural Fiber and Synthetic Substrates

Real, peer-reviewed, dedicated microgreens trial (Agricultural Research Institute Cyprus / University of Naples Federico II) testing 5 substrates on THREE named microgreen species: coriander (cilantro), kohlrabi, and pak choi (pak choi not a row in this calculator). Nutrient solution directly stated (Section 2.2), identical across all substrates and both target species: a quarter-strength modified Hoagland formulation — 2.0 mM nitrate + 0.25 mM ammonium (2.25 mM total N), 0.20 mM phosphorus, 0.62 mM potassium, 0.75 mM calcium, 0.17 mM magnesium, 0.25 mM sulfur, plus micronutrients (20 µM Fe, 9 µM Mn, 0.3 µM Cu, 1.6 µM Zn, 20 µM B, 0.3 µM Mo) — converts to 32N-6P-24K ppm (also Ca 30, Mg 4, S 8 ppm), with EC 0.4 ± 0.1 dS/m and pH 6 ± 0.2, applied by daily manual fertigation, harvested at second-true-leaf stage. PROMOTES Microgreen - Cilantro's and Microgreen - Kohlrabi's NPK/EC/pH from the prior generic shared placeholder (100-22-83, EC 1.0, pH 5.9 — identical across 5 unrelated microgreen rows, the Corrective-Lesson-#4 pattern) to this real, directly-stated, species-exact, dedicated-microgreen-stage figure — both promoted to white/verified. Note this is a considerably more dilute solution than the prior placeholder; the paper's own substrate-comparison results (Section 3.2) confirm both species grew successfully and yielded competitively at this concentration, so dilution is not itself a red flag here — this is a deliberately low-EC quarter-strength Hoagland design point, not an error.

Lay-Walters, Samtani, Fernandez, Blaedow, Havlin, Coneva, Stafne, Lockwood, Bumgarner & Rubio Ames (2026), University of Arkansas Division of Agriculture MP590 — Southeastern Blackberry Nutrient Monitoring and Management

Real, brand-new (2026) multi-university (Virginia Tech/Arkansas/NC State/Auburn/Mississippi State/Tennessee/Georgia) extension guide, the most current blackberry-specific source found this session — field/soil agronomy only. Gives UPDATED 4-stage leaf-tissue sufficiency ranges specific to the southeastern US (Table 2, primocanes 6-12in/small green fruit/floricane peak harvest/floricane post-harvest): N 3.30-4.00%/2.90-3.75%/2.15-3.00%/1.95-2.95%, K 1.30-1.75%/1.30-1.75%/1.15-1.50%/1.00-1.50%, plus P/Ca/Mg/S/Fe/Mn/Zn/Cu/B ranges per stage — a genuine refinement over older single-timepoint leaf-tissue standards. Cites new Arkansas research (Lay-Walters et al. 2026, HortScience) finding that 30-60 lb N/acre/year is sufficient for optimal Ouachita blackberry production, with rates above 90 lb N/acre giving no yield benefit and increasing pruning labor and post-harvest fruit decay — this is LOWER than some older PNW recommendations (50-80 lb N/acre) but still consistent with (brackets) the existing 55 kg/ha (≈49 lb/acre) rate this row's derivation is built from. Also notes blackberries prefer nitrate-based N fertilizers (KNO3, Ca(NO3)2) over ammonium-based sources — a real, directly-relevant qualitative finding, interesting alongside the Duan et al. 2023 papers above which found NH4+/urea outperforming NO3- specifically in a Chinese cultivar/substrate context; the two findings may reflect cultivar or regional differences rather than a contradiction, but are worth holding side by side. Per Rule 8, none of the leaf-tissue data is converted to feed ppm; kept as real, current corroboration only.

Leafy-greens NFT trial (butterhead lettuce, arugula, kale, Malabar spinach) — High Nutrient Concentrations of Hydroponic Solution Can Improve Growth and Nutrient Uptake of Spinach, with paired Kale (Brassica oleracea) data

(EC 1.8 mS/cm, pH 5.8–5.9 — basis for Collard Greens' derived EC/pH, same species as Kale)

Leaves and Soul — Best Fertilizer for Indoor Herbs Lenzi, Orlandini, Bulgari, Ferrante & Bruschi (2019), Foods 8(10):487 — Antioxidant and Mineral Composition of Three Wild Leafy Species: A Comparison Between Microgreens and Baby Greens

Real, peer-reviewed, floating hydroponic trial (University of Florence/CREA, Italy; sister study, shared authors, to the already-cited Bulgari et al. 2016 basil/Swiss chard/rocket microgreens paper elsewhere in this file) comparing three WILD leafy species — Sanguisorba minor (small burnet), Sinapis arvensis (wild mustard), and Taraxacum officinale (common dandelion) — at both the microgreen and baby-green growth stages. All three species were grown on the IDENTICAL generic half-strength Hoagland's solution already used for Basil/Swiss Chard/Arugula's early research via the companion Bulgari paper (N 105, P 15.5 [as 0.5mM], K 117, Ca 100, Mg 24 ppm; EC 1.12 mS/cm; pH 5.56). BASIS FOR the new Microgreen - Dandelion row (added 2026-07-10, per Fred), using this shared recipe at the microgreen stage (105-16-117 ppm, EC 1.12, pH 5.56) — real, species-exact (T. officinale specifically tested), though not individually optimized for dandelion versus the other two wild species tested in the same trial. Wild Mustard (Sinapis arvensis) and Burnet (Sanguisorba minor) remain real, ready-to-use candidates if Fred wants those added too — same recipe, no further sourcing needed. Real findings of note (mineral/antioxidant composition outcomes, not feeding targets): baby greens were generally richer in Ca, Mg, and anthocyanins than microgreens of the same species; S. minor was notably rich in Mg, Zn, Mn, and Mo; Sinapis arvensis (wild mustard) had the highest Ca of the three and, among elements measured, was also comparatively high in Mn and Zn relative to T. officinale; T. officinale microgreens stood out for Fe content among the three; all three showed some Pb/Cd/Cr accumulation (a known ruderal/wild-species trait), with S. minor microgreens specifically exceeding the FAO/WHO Codex Pb limit for leafy vegetables.

LetPot — Hydroponic Herbs: A Beginner's Top 10 List Liopa-Tsakalidi, Salahas & Barouchas — Response of Zucchini to the Electrical Conductivity of the Nutrient Solution in Hydroponic Cultivation

(Technological Education Institute of Western Greece; real hydroponic zucchini glasshouse trial, EC 2.2 and 4.4 dS/m, no significant fruit-weight difference between levels; 2.2 dS/m falls within Squash's existing Veg/Flower EC ranges — basis for the genuine zucchini-specific EC note on Squash, though no full NPK recipe was reported)

Lucini, Borgognone, Rouphael, Cardarelli, Bernardi & Colla (2016), Frontiers in Plant Science 7:948 — Mild Potassium Chloride Stress Alters the Mineral Composition, Hormone Network, and Phenolic Profile in Artichoke Leaves

(University of Tuscia, University of Naples Federico II, CREA, Università Cattolica del Sacro Cuore; real floating-raft hydroponic trial on globe artichoke cv. Romolo — non-saline control nutrient solution: 13 mmol/L NO3-N, 1 mmol/L NH4-N, 1.5 mmol/L P, 5 mmol/L K, 4.5 mmol/L Ca, 2 mmol/L Mg, EC 2.0 dS/m, pH 6.0 — computes to 196N-47P-196K ppm elemental — basis for Artichoke's verified NPK and EC)

Luz, Andrade, Dias, Silva, Haber & Oliveira (2012), Bioscience Journal (Uberlândia) 28(4):589-597 — Hydroponic Production of Cilantro and Curly Parsley Under Nutrient Solution Concentrations and Plant Positions in Hydroponic Profiles

Real, complete, full-text-obtained (user-supplied) NFT trial testing the Furlani et al. 1999 nutrient solution at 50/75/100/125% for BOTH cilantro AND parsley side by side — this is the original agronomic source underlying the trade-press campoenegocios.com recipe already used for Cilantro's NPK, independently confirming that recipe's real-world validity. The 100% recipe (750g Ca(NO3)₂ "hydro especial" + 500g KNO3 + 150g MAP + 400g MgSO4 per 1000L, plus micros) converts to 204N-40P-193K ppm — essentially identical to Cilantro's already-verified 204-40-191. 100% concentration gave the best real, measured yields (fresh mass, leaf count, height) for BOTH species — parsley height specifically peaked at 106.8% concentration, cilantro at 95%, both close enough to the 100% treatment that it's used as the recipe here. Real, directly-measured EC/pH at 100%, by species: Cilantro 1.5 mS/cm / pH 5.8; Parsley 1.6 mS/cm / pH 5.9 — Parsley's figures used here (EC and pH promoted to white/verified). PROMOTES Parsley's NPK to 204-40-193 ppm (kept orange/derived, same salt-to-ppm conversion basis as Cilantro), replacing the prior generic, unsourced 150-31-210 placeholder shared with Cilantro/Dill/Basil. The paper's earlier discussion section also independently cites Santos (2002) finding 75% concentration optimal for parsley in a separate trial and 91.4% optimal per a different measure in this same paper — genus-consistent real range, not conflicting so much as confirming "close to 100%" is right for parsley specifically.

Mattson & Merrill (2016), e-GRO Research Update #2016.04, Cornell University — Symptoms of Common Nutrient Deficiencies in Hydroponic Basil

Real, species-exact ('Genovese' basil) Cornell Cooperative Extension DWC study, primarily documenting deficiency-symptom photography, but Table 1 directly states the complete control nutrient solution in ppm: N 210, P 31, K 235, Ca 200, Mg 49, S 64, Fe 4.0, Mn 0.5, Zn 0.1, B 0.5, Cu 0.10, Mo 0.01. Notably near-identical to the existing verified Khater et al. 2021 figure (210-31-234, Ca 200, Mg 48, S 64) despite independent labs/countries/years — strong corroboration that this row's verified recipe reflects a real, converged basil standard. No change to displayed values (already matches within rounding).

Maximum Yield (Dr. Lynette Morgan, SUNTEC International Hydroponic Consultants) — What Is the Ideal Feed PPM Concentration for Watermelons?

(staged program: Vegetative 243N-67P-208K-258Ca-85Mg-113S ppm at EC 2.0–2.4, Fruiting 202N-91P-322K-169Ca-101Mg-134S ppm at EC 2.0–2.2 — basis for Watermelon's verified NPK and EC, using the Fruiting-stage figure since this calculator does not stage Watermelon by growth phase; a trade-publication source with academic-register staged data, authored by a credentialed hydroponic horticulturist)

Maximum Yield (Dr. Lynette Morgan, SUNTEC International Hydroponic Consultants) — What Types of Nutrients Do Hydroponic Melons Require?

(staged muskmelon program: Seedling/Veg 227N-67P-200K-174Ca-78Mg ppm at EC 2.0–2.4, Flower/early fruit set 209N-85P-276K-174Ca-89Mg ppm, heavy fruit load 183N-120P-448K-174Ca-112Mg ppm — basis for Melons' verified Veg and Flower NPK; a trade-publication source with academic-register staged data, authored by a credentialed hydroponic horticulturist)

MDPI Agronomy (2019, Currey, Walters & Flax) — Nutrient Solution Strength Does Not Interact with the Daily Light Integral to Affect Hydroponic Cilantro, Dill, and Parsley Growth

(Iowa State University; NFT system; tested five DISCRETE EC treatments — 0.5, 1.0, 2.0, 3.0, 4.0 dS/m, not a continuous range — under low and high daily light integral, and found no significant growth difference between EC treatments for any of the three species; pH held at a fixed 6.0 throughout (not a range); 16N-1.8P-14.3K fertilizer (Jack's Hydro FeED) — basis for Cilantro's ORIGINAL derived NPK and pH only, since superseded (see Cilantro's own citations above). NOW ALSO CITED for Dill and Parsley, with the full PDF in hand: the paper reports real, species-specific tissue mineral concentrations for both (e.g. Dill tissue K ranged 4.1–6.2% depending on EC and light; Parsley tissue Ca ranged 0.62–0.84% declining with EC) and confirms the same EC-insensitivity and fixed pH=6.0 finding applies equally to Dill and Parsley as to Cilantro. However, this paper reports TISSUE nutrient content, not a feed-solution N-P-K recipe in ppm, so it never verified or changed Dill's or Parsley's displayed NPK. Dill's EC was later promoted via a species-exact source (Udagawa 1995) — Parsley's NPK/EC/pH have now ALSO been promoted, via a different species-exact source (Luz et al. 2012, see below) — kept here as corroborating context only (wide EC tolerance, pH 6.0 also works).

MDPI Agronomy (Chrysargyris & Tzortzakis) — Nitrogen, Phosphorus, and Potassium Requirements to Improve Portulaca oleracea L. Growth in Hydroponics MDPI Agronomy (Singh, Dunn, Payton & Brandenberger, 2019) — Selection of Fertilizer and Cultivar of Sweet Pepper and Eggplant for Hydroponic Production

(Oklahoma State University; Dutch-bucket trial testing 5N-4.8P-21.6K, 5N-5.2P-21.6K, and 7N-3.9P-4.1K commercial fertilizers, dosed at 3.69 kg/3785.4 L per manufacturer guidance — works out to roughly 49N-20P-175K ppm elemental for the 5-4.8-21.6 formula; EC 2.5–3.5 dS/m, pH 5.5–6.5 for eggplant and 5.5–6 for peppers; calcium nitrate added separately since the K-heavy formulas contained no Ca — basis for the eggplant and pepper Veg derived NPK notes)

MDPI Plants (Rueda Kunz, Laza, Sharma, Sanchez-Plata & Simpson, 2026) — Optimizing Water Volume for Carrots (Daucus carota) Grown in a Deep-Water Culture System

(Texas Tech University; nutrient solution prepared with OASIS® Hydroponic Fertilizer 16-4-17 maintained at 200 ppm N — basis for Carrot's verified NPK, computed against the fertilizer's guaranteed analysis below)

MDPI Plants 12(3):646 — Hydroponic Common-Bean Performance under Reduced N-Supply Level and Rhizobia Application

(real hydroponic common-bean trial with rhizobia inoculation; full nutrient solution composition directly stated in Table 5 — 100%-N standard treatment: NO3 12.6/12.0 mM, NH4 1.2/1.8 mM, H2PO4 1.2 mM, K 5.3/5.0 mM across two growth-cycle stages, EC 1.90–1.93 dS/m, pH 5.50 — computes to 193N-37P-196–207K ppm — added as a confirming, independent alternative recipe to Beans' Fruit-stage Valdez-sourced figures)

MISR Journal of Agricultural Engineering (Biosystems Engineering section) — Chicory Production Under Different Hydroponic Systems Using Magnetized Water at Different Irrigation Rates

(real NFT hydroponic trial on chicory comparing A-shape and gutter system configurations at 1.0/1.5/2.0 L/h flow rates, magnetized vs. non-magnetized solution; non-magnetized A-shape system at 1.5 L/h gave N 162.22, P 24.62, K 181.62, Ca 63.28, Mg 40.07 ppm and pH 5.5–6.3 — basis for Chicory's verified NPK and pH, replacing the prior single-source Howhydroponics figure; magnetization treatment itself is not reflected in this calculator's figures since it is a secondary water-treatment variable, not a base recipe difference. CORRECTION (re-flagged this session): the paper's own EC figure is reported as "≈670 ppm (TDS meter reading)" — a TDS value, not an EC value in mS/cm, the unit every other row in this calculator uses. A prior session displayed this TDS figure directly in the EC column, which is a unit mismatch, not a verified EC. Attempts to access the full thesis/paper text (Alaswad, Benha University, via ResearchGate — see the dedicated thesis citation above) to find whether the source also reports a true EC figure were blocked (429 errors on full-text fetch) — this remains a real access wall, not a non-existent source. EC has since been resolved via two independently-sourced real values below (Oliveira et al. 2023, Andriolo et al. 2008) rather than a converted TDS figure.

Missouri University Extension — Hydroponic Nutrient Solutions (G6984) Miyasaka, Hamasaki & de la Pena (2002), CTAHR Soil and Crop Management SCM-4, University of Hawaii — Nutrient Deficiencies and Excesses in Taro

Real, genus-exact (Colocasia esculenta) UH-CTAHR extension publication, deficiency/toxicity symptom photography drawing on genuine hydroponic-culture experiments run at the University of Hawaii, but the only quantitative table given (Table 1) is leaf-tissue nutrient sufficiency/deficiency/toxicity ranges (e.g. N 4.0–4.5%, P 0.3–0.5%, K 3.2–5.5% of dry leaf tissue) — a diagnostic tissue-analysis standard, not a feeding-solution ppm/EC/pH target, same category distinction already applied elsewhere in this file to other tissue-analysis papers. Does not change Taro's existing verified NPK/pH or its still-unsourced EC.

Mouroutoglou, Kotsiras, Ntatsi & Savvas (2021), Horticulturae 7(11):432 — Impact of the Hydroponic Cropping System on Growth, Yield, and Nutrition of a Greek Sweet Onion (Allium cepa L.) Landrace

Real, peer-reviewed, species-exact (Allium cepa, "Nerokremmydo of Zakynthos" landrace) glasshouse trial comparing four soilless systems (aeroponic, floating, NFT, aggregate) specifically for BULB production — the mature-crop stage this file's Onion pH note has been missing (the existing verified 6.5 is from the Kane thesis's leaf/biomass-stage outcome). This paper directly states "NS pH was recorded daily and adjusted in the range of 5.5–5.7 by adding nitric acid" maintained THROUGHOUT the full growth, bulbing, and maturation cycle (harvest at 95 DAT) — a real, dedicated, mature-bulb-stage pH target. This is LOWER than and does not overlap with Onion's existing white/verified 6.5 (Kane et al. 2006) — a genuine real-vs-real conflict between two dedicated sources at different growth stages (Kane: biomass/leaf outcome at transplant-to-harvest; Mouroutoglou: bulb-specific target through full maturity). NOT applied to override the existing value — flagged as an open item for Fred's choice, same treatment as this file's other multi-source NPK conflicts. The paper's full NPK/EC recipe (Table 2) is real and complete but wasn't extractable from the fetched page text this session — worth a follow-up look if the full PDF becomes accessible, since a real, dedicated bulb-stage NPK figure would be a genuine upgrade over Onion's current source.

Mousavi & Alamzadeh Ansari (2025), Greenhouse Plant Production Journal 2(1):1-17 — Investigating the Effect of Density and Cultivar on Onion Seedling Production in a Floating Culture System

(Shahid Chamran University of Ahvaz, Iran; real, peer-reviewed, genus-exact (Allium cepa, cvs. Ramhormozi and Primavera) floating hydroponic-culture trial, testing seedling density (1/2/6/12 plants per cell) and cultivar. States directly: seedlings were transferred to "a floating culture system containing Hoagland nutrient solution with pH 6.4" — a real, direct, single-value pH reading, landing within Onion's existing derived pH range (6.0–6.5). No N-P-K ppm or EC is stated anywhere in the paper; "Hoagland nutrient solution" is referenced generically without a restated concentration, so this cannot complete or replace Onion's NPK (still sourced to the Kane thesis above) or EC. NOT used to promote Onion's pH to white/verified, since this trial is SEEDLING production (harvested 60 days after sowing, at the seedling stage) rather than mature bulb production — a real stage caveat, consistent with this calculator's general practice of treating seedling/transplant-stage feeding as distinct from mature-crop feeding. Kept as real, genus-exact, hydroponic corroboration for the low-middle of Onion's existing pH range; Onion's pH stays orange/derived. The paper's main density/cultivar findings (fresh/dry weight, leaf area index, chlorophyll content by density and cultivar) are seedling-morphology outcomes, not feeding-solution data, and don't bear on this calculator's NPK/EC/pH fields.

Na, Lee & Park (2001), Acta Horticulturae 548:485-490 (ISHS) — Effects of Magnesium Ion Content in Nutrient Solution on the Growth and Quality of Marjoram

(Korea University; real, peer-reviewed, species-exact (Origanum marjorana) deep-flow hydroponic trial testing Mg2+ at 0.25/0.5/0.75/1.0/1.5 mmol/L against a base herb nutrient solution developed by the European Vegetable R&D Center (Belgium). Table 1 directly states the complete base ion composition in mmol/L: NO3- 18.0, K+ 11.0, PO4 2.0, Ca2+ 4.5, Mg2+ 1.0 (baseline), SO4 1.0, plus a full micronutrient suite (Fe-EDTA 100, B 26, Mn 5.0, Zn 3.7, Mo 0.5, Cu 0.4 µmol/L). Converts to elemental ppm as N 252, P 62, K 430, Ca 180, Mg 24, S 32. REPLACES the prior NC State container-nursery extrapolation (125-27-104 ppm) — this new source is genuinely species-exact, hydroponic (not container/nursery), peer-reviewed, and gives a directly-stated complete elemental solution rather than an N-only rate with P/K back-calculated from a generic fertilizer ratio. Real growth findings: shoot length and fresh weight peaked at 0.75–1.0 mmol/L Mg (the range bracketing this base solution's own 1.0 mmol/L Mg), while essential oil content kept rising up to the highest tested Mg level (1.5 mmol/L) even as growth and chlorophyll declined there — a real yield-vs-quality tradeoff, similar in shape to several other herbs in this file. NPK promoted to white/verified using the base solution's directly-stated composition. EC is not directly stated anywhere in the paper (only the mmol/L salt table), so it stays orange/derived pending a source that states an EC target directly. pH is likewise not stated as a target value in what's available, so it also stays orange/derived.

Nakro, Bamouh, Bouslama, San Bautista & Ghaouti (2023), Horticulturae 9(3):304 — The Effect of Potassium–Nitrogen Balance on the Yield and Quality of Strawberries Grown Under Soilless Conditions

Real, peer-reviewed, species-exact (Fragaria × ananassa, cvs. Fortuna/San Andreas/Sabrina) soilless pot trial (Hassan II Institute, Rabat, Morocco, coarse-sand substrate in 12L bags, drip-fed to 20% drainage — NOT NFT/DWC). Tested three K:N-balance staging programs, each holding total seasonal N/P/Ca/Mg dose identical and varying only K: S1 (K:N 1.3 in growth/2.0 in production — the Moroccan grower-practice control), S2 (2.6/1.0), S3 (3.0/0.6). Table 1 gives the full directly-stated composition (mmol/L, converted here to ppm): GROWTH stage (Nov–Jan, pre-fruiting), constant across all three programs — N 106, P 47, Ca 136, Mg 60 ppm; K varies by program (S1 149, S2 290, S3 344 ppm). PRODUCTION stage (Feb–June, flowering+fruiting) — N 85, P 24, Ca 146, Mg 42 ppm; K varies (S1 174, S2 90, S3 57 ppm). The winning program, S2 (real outcome data: +30% yield/7.9 t/ha, +8% chlorophyll index, +14% total soluble solids, +15% dry matter, +10% taste score, +19% shelf-life, all vs. the S1 grower-practice control), is therefore: Growth 106N-47P-290K ppm (K:N mass ratio ≈2.7) → Production 85N-24P-90K ppm (K:N ratio ≈1.1). NOT applied — kept as a real, flagged, directionally-conflicting citation per Fred's explicit instruction. This directly disagrees with the Yamazaki-based staging already used for this row, which does the opposite (K:N ratio rises from Veg 1.29 → Flower 1.66 → Fruit 1.80, i.e. K builds toward fruiting rather than being front-loaded before it) — that existing staging is itself real and independently corroborated (Yu et al. 2023's own 20–26% yield increase, plus Cornell/SARE and Seoul National University trials). Reasons this wasn't merged despite Nakro et al.'s real, strong outcome data: (1) pot/sand-substrate drip culture, not a circulating hydroponic reservoir — a genuine system-type mismatch with this calculator's model; (2) a fixed-seasonal-total-redistributed-by-timing design, not an instantaneous target-concentration design, so "growth" and "production" here aren't equivalent to this row's Veg/Flower/Fruit stages (their single "production" period spans both Flower and Fruit); (3) Table 1's own stated EC values (2.28–2.77 dS/m growth, 1.60–1.77 dS/m production) don't match the paper's own stated EC target (1–2 dS/m) — an internal inconsistency suggesting these may be as-mixed stock figures rather than confirmed delivered concentrations, a data-quality caveat worth noting. Logged in full for a future session or a deliberate strategy change, not silently discarded.

Naznin, Kitaya, Hirai & Alsanius (2020), Acta Horticulturae 1273:217-222 — Sulfur Fertilization Enhances Ajoene Accumulation in Hydroponically Grown Garlic

(Swedish University of Agricultural Sciences / Osaka Prefecture University; same Naznin research lineage as the EC schedule already cited for Garlic's EC/pH (via Ali et al. 2021) — real hydroponic garlic cv. 'White Roppen' grown for two months in a growth chamber, using a modified Hoagland nutrient solution (OAT House fertilizer/Otsuka) stated in full: NH4-N 17, NO3-N 175, P2O5 90, K2O 304, MgO 45, CaO 173, plus micros, mg/L — converts to 192N-39P-252K ppm, Ca 124, Mg 27 ppm. Sulfur (as K2SO4, 0/2.1/4.1/8.2 mg/L) was the only varied treatment; this base NPK was held flat throughout — sulfur fertilization had no significant effect on fresh or dry biomass but significantly increased ajoene (a sulfur-containing medicinal compound) accumulation in bulb, leaf, and root, with the response saturating between 4.1 and 8.2 mg/L. NOW USED for Garlic's Veg-stage NPK (npkDerived) — see the Veg stage note for the reasoning and its limits.

Naznin, Kitaya, Shibuya & Hirai (2009/2010), Eco-Engineering 21(4):147-152 — Development of Hydroponic Culture System for Producing Garlic and Determination of Ajoene Concentration

(Osaka Prefecture University; UPDATE — full primary PDF now obtained and read directly, superseding the prior secondhand reconstruction below. Real hydroponic garlic cv. 'White Roppen', grown in a growth chamber for two months under controlled 450 µmol m⁻² s⁻¹ light/12h photoperiod, harvested 20/40/60 days after planting, compared against a parallel soil-culture control — hydroponic plants produced 3.1–3.5x more fresh bulb/root/leaf mass and 2.7–4.1x more ajoene than soil-grown plants at 60 DAP. CORRECTION (this session): the paper's own Materials and Methods directly states the AS-USED nutrient solution composition (already at the stated 3/4 strength, not requiring further dilution): NH4-N 2.5, NO3-N 11.5, P2O5 5.2, K2O 7.1, MgO 4, CaO 8.1 mg/L — converting to roughly 14N-2P-6K ppm, Ca 6, Mg 2. This is the SAME implausibly-low figure already flagged as a probable transcription error in the Ali et al. 2021 review's Table 2 (which cites this exact paper) — having now read the primary source directly, that figure is confirmed to originate in this 2009/2010 paper itself, not in the review's secondary transcription. The figure remains implausibly low for any hydroponic feeding solution (even dilute seedling-stage recipes typically run 50+ ppm N) and is still NOT used as a source for Garlic's NPK. RETRACTED: a prior session's reconstruction of "half strength modified-Hoagland's solution (A-type recipe of Otsuka House Solution)" converting to ~130N-79P-168K ppm was built from a secondhand description in a later paper in the same lab series (Naznin et al. 2015) describing this protocol — the primary paper, now read directly, does NOT use this language anywhere and states the much lower figure above instead; the secondhand 130-79-168 reconstruction was incorrect and has been removed from Garlic's Veg-stage blend (see that stage's note for the resulting change). ADDITIONAL CORRECTION: the primary paper states the pH of both hydroponic and soil culture media was a constant 6.7 throughout — not the 5.0–6.0 range previously cited via Ali et al. 2021 Table 4 (which attributes its EC/pH schedule to this same paper); that Table 4 figure cannot be verified against this primary source and is now flagged as a discrepancy rather than removed outright, since Table 4 may describe a different, later trial in the same lab series not contained in this specific 2009/2010 paper. No EC value is stated anywhere in this primary paper — it characterizes solution strength only as a fraction (3/4) of an unstated standard, never in dS/m or mS/cm.)

NC State Extension Gardener Plant Toolbox — Carnation, Chicory, Marjoram

(light requirements; Chicory's own toolbox page — Cichorium intybus, species-exact match for this calculator's Chicory row — tags it "#full sun tolerant" with no shade-preference language; basis for Chicory's verified Light field, upgraded from the single-source Howhydroponics figure. Light requirements are a property of the plant species, not the growing method, so this field-agronomy source applies equally to hydroponic cultivation — it is not being used for, and does not change, Chicory's NPK/EC/pH.)

NC State University / NC A&T State University Extension — Success with Container Production of Twelve Herb Species

(real container/nursery production feeding rates by herb: Rosemary 150–200 ppm N, Sage 200 ppm N, Thyme 125 ppm N, Sweet Marjoram 125 ppm N, weekly constant liquid feed, alternating between 15-0-15 and 20-10-20 fertilizer formulas; P and K for Rosemary/Sage/Thyme in this calculator are derived by applying the stated 20-10-20 formula to each herb's stated N rate, not independently measured — a real but approximated extrapolation, since growers alternate formulas rather than running 20-10-20 continuously. Marjoram's figure here is SUPERSEDED — see the Na, Lee & Park citation below for a species-exact hydroponic replacement.)

Neocleous, Nikolaou, Ntatsi & Savvas (2020), Agronomy 10(6):881 — Impact of Chelated or Inorganic Manganese and Zinc Applications in Closed Hydroponic Bean Crops on Growth, Yield, Photosynthesis, and Nutrient Uptake

(Agricultural Research Institute of Cyprus / University of Thessaly / Agricultural University of Athens; real closed-loop NFT common bean trial, cv. 'Moraleda', Mediterranean greenhouse, two cropping seasons (spring-summer and autumn-winter) — tested chelated (EDTA) vs. inorganic (sulphate) forms of Mn and/or Zn in the replenishment nutrient solution; found NO significant difference in pod yield, growth, photosynthesis, or tissue nutrient status between chelate forms, so this is not a basis for changing Beans' Mn/Zn sourcing, just for its base N-P-K-Ca-Mg recipe. The paper's own directly-applied replenishment nutrient solution, based on Savvas (2012)'s Mediterranean soilless bean recommendations: vegetative stage 4.8mM K/2.5mM Ca/1.1mM Mg/1.4mM NH4+9.9mM NO3/1.0mM H2PO4 → 158N-31P-188K-100Ca-27Mg ppm, EC 1.6 dS/m, pH 5.6; reproductive stage 5.6mM K/1.9mM Ca/0.85mM Mg/1.2mM NH4+9.2mM NO3/1.0mM H2PO4 → 146N-31P-219K-76Ca-21Mg ppm, EC 1.5 dS/m. Pod yield averaged 9.7 kg/m² across treatments. NOW USED as a real, independent corroborating citation for Beans' Veg-stage NPK/EC/pH — see that cell's note. The paper's own measured uptake concentrations (UCs, mass absorbed per volume of water transpired, distinct from the applied recipe) averaged roughly 160N-28P-211K-80Ca-22Mg ppm across both seasons — included here for completeness but NOT used as the cited recipe figure, since UC describes what the plant absorbed, not what should be fed.

Nicola, Hoeberechts & Fontana (2004), Acta Horticulturae 633:467-473 — A Soilless Culture System to Grow Out-of-Season Asparagus with a High Marketable Value

(Università di Torino, Italy; real two-year greenhouse forcing trial, cv. 'Eros', species-exact (Asparagus officinalis). Tested local soil vs. a genuinely inert 60% peat/40% perlite growing medium in plastic boxes, fertilized weekly or biweekly with 1 g/L of Tipo OT™ (Valagro), "a commercial solution for hydroponics." UPGRADE: the paper's own Table 1 directly states Tipo OT's complete composition in mol/kg of product (N 2.7143, P 0.2258, K 1.0641, Ca 0.6250, Mg 0.2000) — converting via atomic weights at the stated 1 g/L application rate gives a complete N-P-K-Ca-Mg figure: 38N-7P-42K ppm (Ca 25, Mg 5). This REPLACES Asparagus's prior NPK figure, which was a generic ratio-to-ppm structural placeholder (EC-anchor formula applied to an unsupported fertilizer-label ratio) with no underlying crop-specific evidence of any kind — this real, named, genus-exact commercial-product recipe, directly applied to asparagus in a qualifying inert substrate, is materially stronger evidence even though it disagrees substantially with the prior placeholder number. Kept orange/derived (not promoted to white) since the ppm conversion is this calculator's own math from the paper's stated mol/kg figures, not a number the paper states directly in ppm. Fertilization schedule (weekly vs. biweekly) did not significantly affect spear yield in either year of the trial — used here as confirmation that this is a real, stable working recipe rather than evidence the specific rate matters. The paper gives no EC or pH value for the nutrient solution (Asparagus's existing white-tier EC/pH, sourced separately, is unaffected).)

Northeast Paulista Field Station (Paulista Agency of Agribusiness Technology, Brazil) — Growth and Nutrient Absorption by Beet Grown in Hydroponic System

(NFT table-beet trial, highest yield at EC 1.6 dS/m)

Nutrient Solutions for Greenhouse Crops (van der Lugt et al., Nouryon/AkzoNobel, SQM, Yara, Eurofins Agro, NMI — based on Sonneveld & Voogt 2009, "Plant Nutrition of Greenhouse Crops")

— Cucumber, Eggplant, Melon, and Strawberry N-P-K ppm targets by growth stage (Start/Fruit Set/High water/End season), for inert substrate, organic substrate, and soil-grown variants of each crop — basis for Eggplant's verified Veg ("Start" stage) and Flower ("Fruit Set" stage) NPK, in addition to the existing Fruit-stage figures for Cucumber, Eggplant, Melon, and Strawberry. Independently confirmed by direct access to Sonneveld & Voogt's own Appendix C ("Nutrient Solutions for Different Vegetable and Cut Flower Crops") — the Eggplant "root environment" figures in Appendix C (287N-28P-242K ppm) exactly match the Veg-stage figure derived from this manual; Appendix C itself only covers Tomato, Cucumber, Sweet Pepper, Eggplant, Lettuce, Chrysanthemum, Rose, Gerbera, Cymbidium, Anthurium, Potted plants, and Hippeastrum — none of which are otherwise-unresolved crops in this calculator

OASIS Grower Solutions — Hydroponic Fertilizer 16-4-17 Guaranteed Analysis

(16% N, 4% available P₂O₅, 17% soluble K₂O, 4% Ca, 1.5% Mg) — at the Rueda Kunz et al. 2026 study's 200 ppm N application rate, this works out to 200N-22P-176K ppm elemental (P₂O₅×0.436, K₂O×0.830), plus 50 ppm Ca and 19 ppm Mg — basis for Carrot's verified NPK

Ohio State University Extension — Hydroponic Nutrient Solution for Optimized Greenhouse Tomato Production

(HYG-1437, Jensen/UA-CEA 3-Stage recipe — Table 3 gives full N-P-K ppm for all three stages, verifying Tomato's complete Veg/Flower/Fruit progression)

Ohio State University Extension — Planting Roses

(HYG-1212-96, light requirements)

Oklahoma State University Extension — Electrical Conductivity and pH Guide for Hydroponics (HLA-6722, Singh & Dunn, 2016)

— Table 2 gives EC/pH targets for African Violet, Asparagus, Banana, Bean, Basil, Bok Choy, Broccoli, Cabbage, Carnation, Celery, Courgettes, Cucumber, Eggplant, Ficus, Leek, Lettuce, Marrow, Okra, Parsley, Peppers, Rhubarb, Rose, Sage, Spinach, Strawberry, and Tomato — basis for Banana's EC (1.8–2.2, upgraded from the single-source Howhydroponics figure since this independent extension table gives the identical EC range) — NOTE (2026-07-11): this table's 5.5–6.5 pH figure for Banana has since been SUPERSEDED by a directly-stated, narrower pH from a Chinese hydroponic banana patent (CN102992835A, see citation above/below) — this table remains Banana's EC source only, not its pH source; confirms the existing Asparagus and Okra EC/pH figures already in use; and this session corrected a stale citation-vs-render mismatch — Table 2's exact 1.6–2.0 EC / 5.5–6.0 pH for Rhubarb and 1.0–1.6 EC / 5.5–6.5 pH for Sage were already cited here but the underlying data flags had not been updated to render white (Rhubarb still carried a stale Howhydroponics flag, Sage was still unverified) — both fixed to white this session. Also basis for Green Beans' verified EC/pH (Table 2's "Bean" entry gives the identical 2.0–4.0 EC / 6.0 pH); Green Beans' NPK remains separately orange/derived since Table 2 gives no NPK figures. ALSO USED as the basis for African Violet's verified EC AND pH: Table 2 gives EC 1.2–1.5 and pH 6.0–7.0 for African Violet, replacing the prior flat, uncited EC of 0.8 and the prior pH of 5.8–6.5 that traced to a different, less specific source — both fields now adopted directly from this real, named-author university extension table. African Violet's NPK remains separately orange/derived, since Table 2 gives no NPK figures. NOTE (this session): Table 2's EC figure for Bok Choy (1.5–2.0) was superseded by a species-specific source (see Oliveira et al. 2024 below) — this table is now Bok Choy's pH source only (7.0), not its EC source.

Olfati, Khasmakhi-Sabet & Shabani (2012), International Journal of Vegetable Science 18(3):298-304 — Nutrient Solutions on Yield and Quality of Basil and Cress

Real, peer-reviewed, species-exact (Ocimum basilicum) NFT hydroponic trial (University of Guilan, Iran), comparing four real nutrient solutions varying total N and NH4:NO3 ratio (Table 2 gives complete meq/L compositions). Found nitrate positively affects basil yield and quality, while ammonium does not — the two lowest-total-N, higher-NH4 solutions (3 and 4) gave the lowest basil yield, while the two higher-nitrate solutions (1 and 2) gave the best. Real, genus-exact corroboration that basil favors nitrate-forward, moderate-to-full-strength feeding — consistent with, but not more specific than, Basil's existing verified Khater et al. 2021 figure; not used to override. Also grew garden CRESS (Lepidium sativum) side by side in the same trial, finding the OPPOSITE pattern — cress performed best under solution 3 (lower total N, higher NH4 ratio: real, complete composition computable from Table 2 as ≈67N-51P-107K ppm, Ca 53, Mg 9) — flagged as a real, usable candidate recipe for a possible new Cress row, but NOT added this session since the paper states no EC or pH target for either crop, and adding a new row with two of three core fields completely unsourced would need Fred's judgment call on how to handle the gap.

Oliveira, Costa, Oliveira, Oliveira, Silva, Góis & Ribeiro Filho (2024), Revista Caatinga 37:e12436 — Production and Quality of Pak Choi Grown in Different Hydroponic Systems and Electrical Conductivities

(Federal Rural University of the Semi-Arid Region, Brazil; real, species-exact (Brassica campestris var. chinensis) factorial trial comparing NFT and semi-hydroponic substrate systems across five EC levels, 1.0–5.0 dS/m. Number of leaves, leaf succulence, and specific leaf area (pooled across both systems) all peaked quadratically between EC 3.1–3.4 dS/m. Leaf area, shoot fresh mass, and shoot dry mass diverged by system: NFT peaked quadratically at EC 3.0–3.1 dS/m, while substrate culture kept climbing linearly through the highest tested EC (5.0) with no plateau reached. Post-harvest firmness and soluble solids both declined with increasing EC in both systems. The paper's own stated synthesis: "highest plant growth occurred close to EC of 3 dS/m for the NFT system," consistent with prior literature it cites (Ding et al. 2018: 2.4–4.8 dS/m; Niu, Sun & Masabni 2018: 2.4–3.2 dS/m) classifying pak choi as moderately salt-tolerant. This calculator does not distinguish hydroponic system sub-types, so the NFT-anchored growth optimum (the more common hobbyist/small-scale method) was adopted — basis for Bok Choy's verified EC (3.0–3.4 dS/m), replacing the prior generic Oklahoma State University Extension HLA-6722 figure (1.5–2.0 dS/m), which came from a 25-plus-crop general reference table rather than species-specific research. NPK previously remained separately orange/derived — see Kano et al. (2021) below, which now supplies a real species-exact NPK figure. pH (7.0) is retained from the OSU source since this paper does not report a pH finding.

Oliveira, Dantas, Ramos, Oliveira, Pinto, Oliveira, Costa, Oliveira, Góis & Dias (2025), Revista Brasileira de Engenharia Agrícola e Ambiental 29(7):e291132 — Endive Production Under Different Hydroponic Systems and Electrical Conductivities of the Nutrient Solution

Real greenhouse split-plot trial on endive (Cichorium endivia), comparing three hydroponic system types — nutrient film technique (NFT), semi-hydroponic (SH), and deep flow technique (DFT) — each at two electrical conductivities (1.6 and 2.9 dS/m). Findings are genuinely system-dependent rather than one clean number: SH gave the best overall shoot dry mass (12.46 g/plant) and was unaffected by EC; DFT performed best at the LOWER EC (1.6), declining at 2.9; NFT showed no significant EC effect on its own but needed the HIGHER EC (2.9) just to match SH's performance, suggesting NFT is more nutritionally demanding for this crop. The paper's own stated recommendation: EC 1.6 dS/m for SH and DFT systems, EC 2.9 dS/m for NFT specifically. This calculator does not distinguish hydroponic system sub-types, so the lower, more broadly-applicable SH/DFT figure (1.6) was adopted as Endive's single verified EC value, replacing the prior vague 1.0–1.8 range — basis for Endive's verified EC. NPK and pH remain separately orange/derived, since this paper reports neither.

Oliveira, Santos Júnior, Silva, Gheyi, Almeida & Guiselini (2023), Revista Brasileira de Engenharia Agrícola e Ambiental 27(9):719-728 — Cultivation of Chicory Under Nutrient Solutions Prepared in Brackish Waters and Applied at Different Temperatures

Real, peer-reviewed, species-exact (Cichorium intybus, cv. Folha Larga — Brazilian Portuguese "almeirão") NFT hydroponic trial testing root-zone temperature and salinity stress. The paper's own base recipe (before NaCl stress additions), built on Furlani et al. 1999's leafy-vegetable formula, is directly stated in mmol/L: N 13.59, Ca 2.37, K 5.50, P 2.61, S 1.37, Mg 1.48 (≈190N-81P-215K ppm, Ca 95, Mg 36, S 44), contributing EC 1.58 dS/m from fertilizer alone plus 0.12 dS/m background water EC, for a real, directly-measured control ECns of 1.7 dS/m (the paper's own "control" treatment, before any salinity stress was added) — one of two new sources used to resolve Chicory's long-standing "670 ppm TDS, unconvertible" EC placeholder (see Andriolo et al. 2008 below for the second). pH was monitored (not tightly corrected) and ranged 5.50–7.50 over most of the cycle — broadly consistent with, but not narrower than, the existing 5.5–6.3 range, so not used to change the displayed pH. NPK is real, complete, and directly stated but disagrees substantially with the existing Alaswad/MISR figure (162-25-182), especially on P (81 vs 25 ppm) — logged as a real, corroborating-yet-conflicting citation, not used to override, since three independently-sourced real Chicory NPK recipes (this paper, Andriolo et al. 2008 below, and the existing MISR figure) now disagree with each other and picking among them needs Fred's judgment.

Pacheco, Duarte, Charles, Nascimento, Simões, Campos Júnior, de Almeida, Ricardo, Lopes, Ferreira de Jesus & Lisboa (2023), Brazilian Archives of Biology and Technology 66:e23210845 — Electrical Conductivity and Nitrogen:Potassium Ratios from Nutrigation in the Quality of Zucchini Fruits

(ESALQ/USP & UFRA, Brazil; real soilless pot-culture zucchini cv. Corona trial, AgroLink commercial substrate, drip fertigation, 5 EC levels (1.0–5.0 dS/m) × 3 N:K ratios (2:1, 1:1, 1:2), Hoagland-based — full nutrient composition stated directly per treatment in Table 1. Found the 1:2 N:K ratio gave the largest fruits, highest pulp thickness, and highest water content; for fruit fresh mass specifically, the 1:1 and 1:2 ratios both peaked around EC≈2.9 dS/m (regression-calculated), while the 2:1 ratio peaked at the lowest tested EC (1.0). Separately, total whole-plant dry mass peaked at different ECs per ratio (2:1 at 1.0, 1:1 at 3.7, 1:2 at 5.0) — a different outcome variable from fruit fresh mass. NOW USED for Squash, Summer's verified Fruit-stage NPK (the 1:2 ratio at EC level 3, the nearest tested point to the 2.9 fresh-mass optimum): 209N-31P-425K-199Ca-48Mg-63S ppm — see that cell's note for the full reasoning, including why fresh mass was prioritized over the dry-mass finding)

Paglialunga, El Nakhel, Proietti, Moscatello, Battistelli, Formisano, Ciriello, Del Bianco, De Pascale & Rouphael (2023), Frontiers in Sustainable Food Systems 7:1222914 — Substrate and Fertigation Management Modulate Microgreens Production, Quality and Resource Efficiency

Real, space-farming-oriented, dedicated trial (CNR/University of Naples/Italian Space Agency) on RADISH (Raphanus sativus cv. Saxa 2) and Savoy Cabbage (Brassica oleracea var. capitata f. sabauda cv. Vertus) specifically. Tested two substrates (coconut fiber, cellulose sponge) and two NS regimes: quarter-strength Hoagland (QS, real, EC 0.4±0.05 mS/cm, pH 6±0.2) throughout, or half-strength Hoagland for the first half of the cycle then osmotic water only (HS/H2O, initial EC 0.8±0.05 mS/cm, pH 6±0.2). No elemental N-P-K ppm table given (concentrations described only as "quarter/half-strength Hoagland"), so EC/pH only. FLAGGED, NOT APPLIED: this is a genuine, species-specific, real EC/pH pair for Radish. UPDATE (2026-07-10, per Fred's explicit choice): Radish's displayed EC/pH is now sourced to the Balik et al. 2024 quarter-strength recipe below (1.2–1.6/5.5), replacing the prior Di Gioia 17-species shared-solution figure (1.3/6.2) — this paper's dedicated-but-incomplete (no NPK) EC/pH pair (0.4–0.8/6.0) remains a real, unresolved alternative, now conflicting with Balik's figure rather than Di Gioia's. Not adopted; logged as an ongoing conflict.

Palmitessa, Renna, Crupi, Lovece, Corbo & Santamaria (2020), Foods 9(5):677 — Yield and Quality Characteristics of Brassica Microgreens as Affected by the NH4:NO3 Molar Ratio and Strength of the Nutrient Solution

Real, dedicated, full-primary-text-read trial (University of Bari) on Broccoli, Broccoli Raab, and Cauliflower microgreens — same paper as the PMC7278818/mdpi 2304-8158/9/5/677 listing (duplicate URLs, one article). Table 1 states the half-strength Hoagland-type solution used directly in mg/L: N-NO3 100 + N-NH4 5 (=105 total N), K 117, P 16, Mg 24, Ca 86, S 31, pH 6.5, EC 1.37 mS/cm — this is the primary-source confirmation of the figure already displayed for Broccoli (105-16-117, EC 1.3, pH 6.2, originally sourced via the Di Gioia et al. citation chain) — essentially an exact match, now doubly verified. Table 2 additionally reports three NH4:NO3 molar-ratio variants (5:95/15:85/25:75) at the same total concentration, with pH shifting to 6.3/5.9/5.8 and EC to 1.12/1.42/1.40 as the ammonium fraction increases — real, but a secondary variable (N-form ratio) rather than a concentration change; not applied. Real, confirms the existing figure rather than conflicting with it.

Paulus, Medeiros, Santos & Paulus (2008), Horticultura Brasileira 26(1):61-67 — Nutrient Solution for Mint Production in Hydroponic Solution

(Real, peer-reviewed NFT trial, also species-exact for Mentha arvensis (Japanese/corn mint) like the Sae-Chua citation above. Unlike Sae-Chua's CTRL (an incidental deficiency-study baseline), this recipe WAS the paper's actual tested/optimized variable, directly stated as elemental mg/L: K+ 299.52, Ca++ 79.60, Mg++ 34.80, N-NO3- 211.40, P-H2PO4 27.90, S-SO4 11.84 (≈ 211N-28P-300K ppm), reaching EC 1.99 mS/cm at 100% strength (dropping to 0.88–2.06 over the crop cycle as nutrients were absorbed), pH target 6.0±0.2 (ranged 5.0–7.0). This 100%-strength, 50%-replacement-on-EC-drop treatment gave the paper's best real outcomes: highest dry biomass (45 g/plant), essential oil (0.60 mL/100g fresh leaf), and menthol content (82.4%) among all treatments tested, and outperformed field-grown mint on all three metrics. NOTABLE: this recipe's N and P land very close to Sae-Chua's independent CTRL baseline (211 vs 210 N; 28 vs 30 P) despite being a different lab, country, and decade — a real, notable convergence between two independent Mentha arvensis sources, both sitting well above this row's currently-displayed 150-50-200 figure (sourced from Treadwell et al., Mentha spicata) particularly on N and K. CORRECTED THIS SESSION: this row is already explicitly declared to represent Mentha spicata/piperita (see the Treadwell et al. 2011 citation above, "the same species this calculator's Mint row represents") — Mentha arvensis (Japanese/corn mint, grown industrially for menthol oil) is agronomically a distinct crop from culinary spearmint/peppermint, so this is NOT an open species-identity question for this row, despite earlier phrasing here suggesting otherwise. NOT applied to the displayed NPK, since it's a real but off-species figure — kept as citation-only corroboration that the genus generally tolerates a range of N/K levels.

Petersen, Demann, Restemeyer, Olfs, Westendarp, Appenroth & Ulbrich (2022), Plants 11(8):1010 — Influence of Light Intensity and Spectrum on Duckweed Growth and Proteins in a Small-Scale, Re-Circulating Indoor Vertical Farm

Real, species-exact (Lemna minor, also tested Wolffiella hyalina) indoor vertical-farm trial, primarily a light-intensity/spectrum study, but its nutrient dosing target is directly stated: EC 0.6 mS/cm, corresponding to a solution (mM): NO3-N 0.76, NH4-N 0.25, PO4 0.1, K+ 0.91, Mg2+ 0.13, SO4 0.32, Ca+ 0.22 — converts to roughly 14N-3P-36K-3Mg-9Ca ppm. PER FRED'S EXPLICIT CHOICE (2026-07-11), now APPLIED to Duckweed's displayed NPK (14-3-36, promoted to white/verified — REPLACES the prior unevidenced 24-3-25 placeholder), resolving that leg of the standing 4-way NPK conflict (see the Jin et al. 4x-Hoagland and Leng/Stambolie/Bell notes elsewhere in this file for the other three, now-superseded alternatives). pH was not a controlled target in this trial (drifted from 7.6 to ~7.8–7.9 over the recirculating run) — not used to override the existing dedicated pH-optimum source, which is now white/verified in its own right (see the Hicks 1932 and Akyüz & Ersus 2024 notes for that resolved conflict).

PLOS ONE (China Agricultural University) — quadratic-regression study (36 treatments) on combined N/P/K/water effects in greenhouse strawberry

; found N most important factor overall, optimal range N 156–172, P 54–63, K 484–543 ppm for yield above 110 g/plant — basis for the alternative higher-K strawberry note

PonicsLife — Hydroponic Charts for Fruits and Vegetables: pH, TDS, EC, cF, PPM Produce Grower — Edible Crop Species Differ in Their pH Effect in Hydroponics Proponics — Hydroponic Onions: A Grower's Guide PubMed Central (Technological Institute of Torreón) — modified Steiner Universal Nutrient Solution study testing 12 N/K combinations in hydroponic strawberry

; 168N-430K ppm gave best combined yield and antioxidant/Brix quality — basis for the alternative higher-K strawberry note

PubMed Central — Peer-reviewed hydroponic research (Purslane, Duckweed, Gotu Kola, Strawberry) PubMed Central — Substrate System Outperforms Water-Culture Systems for Hydroponic Strawberry Production Qiu, Gaudreau, Nemati, Gosselin & Desjardins (2017), European Journal of Horticultural Science 82(2):72-80 — Primocane Red Raspberry Response to Fertigation EC, Types of Substrate and Propagation Methods

(Université Laval, Canada/Fafard et Frères; real two-year soilless high-tunnel trial, cv. 'Autumn Britten', testing three fertigation EC regimes — constant 1.2 dS/m (control); 1.2→0.8 dS/m before/after flowering (lower EC); 1.6→1.2 dS/m before/after flowering (higher EC) — plus three substrates (peat/bark, peat/biochar, peat/coco fiber) and two propagation methods. Found NO significant effect of any EC treatment on plant growth, dry biomass, or marketable yield over either year — basis for Raspberry's extrapolated EC range in this calculator (the verified Bazangeya et al. 2025 NPK source did not report an EC value of its own); this paper's null EC result supports treating raspberry as relatively EC-insensitive within the ~0.8–1.6 dS/m band tested, rather than pinpointing one specific optimal value)

Revista Brasileira de Fruticultura (Marques et al., 2019) — Production of Passion Fruit in a Semi-Hydroponic System Under Protected Cultivation

(slabs system, explicit nutrient solution: 145N-29P-40K ppm, best-performing EC 2.72–2.95 mS/cm)

Ramadhan, R. (2019), Universitas Jenderal Soedirman (Skripsi) — Effect of Various EC Values on Growth and Yield of Three Shallot Varieties (Allium ascalonicum L.) Hydroponically

Real, species-exact, genuinely hydroponic (screen-house split-plot trial, Purwokerto, Indonesia) shallot study — three real EC levels tested (1, 2, and 3 mS/cm, clean units with no TDS-ppm-scale ambiguity) across three varieties (Bima Brebes, Batu Ijo, Super Philip). Real, direct finding from the abstract: EC 1 mS/cm gave the best bulb volume and fresh/dry bulb weight across all three varieties — Batu Ijo performed best overall for bulb size/yield, Bima Brebes for leaf/tiller/bulb count. Full methodology chapters (Bab I-V) are restricted to repository staff, so only the abstract-level finding is confirmed. PROMOTES Shallot's EC to white/verified at 1.0 mS/cm, replacing the prior orange/derived 1.4–1.8 range and directly resolving the standing "Shallot's EC/TDS genuinely unresolvable" open item — this source states clean mS/cm units throughout, sidestepping the TDS-ppm conversion-factor ambiguity that made the prior figure unresolvable. No NPK data given (this is an EC-only study); Shallot's NPK remains unchanged, still orange/derived.

Rhban, Malakh & Obaid (2022), Syrian Journal of Agricultural Research 9(6):232-249 — Effect of Growth Media Composition and Nutrient Solution Concentration on Rosemary Growth and Productivity Parameters (Rosmarinus officinalis L.)

(Aleppo University / Damascus University, Syria; real, species-exact, genuinely-hydroponic (deep flow technique, DFT) rosemary trial — the ONLY hydroponic-specific rosemary source found so far, vs. the container/nursery-production extrapolation above. Five growth media tested (soil control, peat moss, peat moss:pumice 1:1, peat moss:perlite 1:1, DFT hydroponic) crossed with two Hoagland's solution concentrations (full-strength "X" and half-strength "0.5X"). Real, growth-outcome-validated finding: half-strength (0.5X) Hoagland's significantly outperformed full-strength (X) for nearly every measured trait across ALL media types — vegetative fresh/dry weight, essential-oil percentage, and (for the DFT hydroponic treatment specifically) root fresh/dry weight and lateral-root length, which were also the single best-performing treatment of the whole trial. NOT used to change Rosemary's displayed EC, since the paper's own text (the portion available this session) states the growth media's physical/chemical properties in a table but does not restate Hoagland's own N-P-K-ppm or EC composition anywhere — "X" and "0.5X" are never converted to explicit ppm or dS/m figures in the paper itself, so promoting to a specific EC number would require assuming a standard Hoagland concentration the source doesn't state. Conventional full-strength Hoagland's is cited elsewhere in this file at roughly EC 2.0 dS/m (see the Onion/Kane citation and USDA ARS Hoagland recipe), which would put this paper's real 0.5X optimum at roughly EC 1.0 — landing right at the low end of Rosemary's existing derived 1.0–1.6 range, a real corroboration of that end of the range, though not a directly-stated figure from this paper on its own. Kept as a real, genus-exact, DFT-hydroponic citation supporting the existing EC range at its lower bound; NPK stays sourced to the NC State container-feeding extrapolation above, unchanged.

Ries, Meng & Park (2025), HortScience 60(2):198–204 — Potassium Sulfate Supplementation with Elevated Electrical Conductivity Was Unproductive for Hydroponic Strawberry at the Original Yamazaki Nutrient Solution Nitrogen Level

(primary source for the Ries et al. DWC strawberry K trial cited above — tested initial K of 117/194/271/348 mg/L against fixed N of 77 mg/L in deep water culture; confirms no yield/quality benefit from raising K past 117 mg/L in DWC specifically)

Roosta, H.R. (Vali-e-Asr University of Rafsanjan) — Effect of Nutrient Solution pH on the Vegetative and Reproductive Growth of Rose cv. 'Grand Gala' in Hydroponic System

(pH 6.5 confirmed optimal — basis for Rose's verified pH)

Sae-Chua, Amsonsri, Wangkarn & Sommano (2019), PeerJ 7:e7751 — Physiological Responses of Hydroponically-Grown Japanese Mint Under Nutrient Deficiency

(Chiang Mai University, Thailand; real, peer-reviewed, deep-water-culture hydroponic trial on Japanese mint (Mentha arvensis — a different Mentha species than this row's Treadwell/Tabatabaie sources, both Mentha spicata/piperita), testing macro/micronutrient deficiencies against a complete control (CTRL). CTRL is directly stated in mg/L: 210 N, 30 P, 234 K, 200 Ca, 64 S, 48 Mg, pH 6.5–7.0, EC 1.9–2.0 mS/cm — close to, but not identical to, this row's already-verified 150-50-200 figure (this recipe has more N and K, similar Ca/S/Mg, and a higher EC than the 1.4 dS/m already sourced from Tabatabaie above). NOT used to change Mint's displayed NPK/EC, since the CTRL here was the paper's deficiency-study BASELINE (used to isolate the effect of removing individual nutrients), not itself the tested/optimized variable — same "incidental feeding detail, not the paper's tested variable" situation as several other citations in this file. Kept as real, genus-exact corroboration that this row's verified figures sit in a plausible range for Mentha species generally.

Safaei, Alirezalu, Noruzi & Alirezalu (2024), BMC Plant Biology 24:968 — Phytochemical and Morpho-Physiological Response of Melissa officinalis L. to Different NH4+ to NO3⁻ Ratios Under Hydroponic Cultivation

Real, recent, peer-reviewed, genus-exact (Melissa officinalis) trial, Urmia University, Iran — floating culture system (FCS), 200L containers, 16 plants/container, testing 5 NH4+:NO3⁻ ratios (100:0 through 0:100) at a STATED-CONSTANT total N and total-nutrient concentration across all treatments (only the ammonium:nitrate split varied, not the absolute strength). RESOLVED THIS SESSION — Table 1 (user-supplied) gives the full base recipe directly in mM, constant across all five NH4:NO3 treatments: N 15, H2PO4⁻ 1.97, K⁺ 7.10, Ca²⁺ 4.41, Mg²⁺ 1.87 — converts to 210N-61P-277K ppm, Ca 176, Mg 45. This is a REAL, complete, directly-stated, genus-exact figure, but notably different from the Son et al. 2021 figure currently displayed for Lemon Balm (354-186-420 ppm, see citation below) — not applied to the displayed NPK pending Fred's choice of which real source to use (or whether to note both). Other real findings from this paper, unaffected by the resolution: pure-ammonium (100:0) plants died from NH4+ toxicity at the seedling stage; growth/biomass/plant height were maximized at the pure-nitrate (0:100) end, while leaf tissue N and K percentage (not feeding-solution ppm — a tissue measurement) peaked instead at 75:25 NH4+:NO3⁻. Confirms lemon balm strongly prefers nitrate-dominant N over ammonium, consistent with this calculator's general convention of nitrate-dominant recipes elsewhere.

Salvador, Minami & Jadoski (2005), ISHS Acta Horticulturae 697:125-132 — Evaluation of Different Substrates on African Violet (Saintpaulia ionantha Wendl.) Growth

Real, species-exact (Saintpaulia ionantha) trial, ESALQ/USP & UNICENTRO, Brazil — checked specifically for any usable African Violet NPK upgrade. CONSIDERED AND DECLINED: this is a POTTED-SUBSTRATE physical-properties study (testing carbonized rice hull/sand/peat/vermiculite/eucalyptus-bark/earthworm-humus mixtures for density, total porosity, air space, and water retention), not a hydroponic nutrient-solution trial — the substrates used are organic, water/nutrient-retentive potting media, not the inert, non-nutrient-contributing substrates this calculator's standing hydroponic definition requires (see the file-wide Rule 7/8 definition). Fertilization is incidental background, held constant across all treatments rather than itself tested: a fungicide ("Manzate," 1.0 g/L) and a commercial blend ("Cristalon Phosphate + micronutrients," 8.0 g/L) with no N-P-K breakdown given for either. A separate fertirrigation stock solution IS given in full salt-by-salt form (250g MgSO4·7H2O + 500g KNO3 + 1500g calcium nitrate per 36L stock, diluted 4L stock per 1000L irrigation water, stated EC 0.9 mS/cm) — converts to roughly 27-36N ppm (range reflects an unstated calcium nitrate hydration form) ppm, Ca 28-41, Mg 3, K 21 — but this stock solution is only ONE of at least two fertilization inputs used in the trial (the Cristalon/Casumin products are undisclosed), so even this real, calculable figure does not represent the complete feeding program, and the substrate-based (not inert-substrate) growing method keeps it out of scope per this calculator's hydroponic definition regardless. NOT used to change African Violet's NPK/EC/pH. Kept as a real, on-topic, citation-only reference — its low EC (0.9) and low N are broadly consistent with the existing UF/IFAS EC<0.8 ceiling and African violet's general reputation as a light feeder, which is corroborating context even though the figure itself isn't adoptable.

Salve Regina University Hydroponic Growing Guide (Russell, 2022) — Bell Pepper (Capsicum annuum) in Grow Tent

Real, named, genus-exact student hydroponic-growing guide (Salve Regina University, flood-and-drain nutrient-film mega-garden grow tent, high-pressure sodium lamp), same series and same institution as the Peas guide above. States a target pH of 6.0–6.5 and nutrients "General Hydroponics: 1:1.5 ratio of FloraMicro:FloraGro, ranging between 1400 and 1750 ppm" (its "Target PPM:" field is left blank in the source document, and "First Harvest on day:" is listed as "TBA" — an incomplete, unfinished report). NOT USABLE — CORRECTED REASONING this session (per Fred): using a commercial product within an academic study does not itself disqualify a source; the actual reasons this stays unused are that the guide's own harvest data was never completed and its "1400–1750 ppm" figure is an undifferentiated total-TDS/EC-style reading, not an elemental N-P-K breakdown, so there is nothing extractable to apply regardless of the fertilizer brand involved. Peppers' existing staged NPK/EC/pH (already white/verified from other, unrelated hydroponic-specific sources) is unaffected — this citation changes nothing.

SARE / University of New Hampshire (DeVitto & Poleatewich, GNE18-169 final report, 2020) — Expanding Northeast Strawberry Production in Controlled Environment Agriculture with Naturally-Derived Nutrient Source

— used the original 1982 Yamazaki strawberry formula directly (Table 2: NO3 70, NH4 7, PO4 15, K 117 mg/L), EC 1.0 mS/cm, pH 5.5 — cross-validates Strawberry's Veg-stage K figure exactly

Science in Hydroponics — Comparing Nutrient Solutions for Hydroponic Strawberry Production

(cites the Torreón modified-Steiner study and the China Agricultural University quadratic-regression study below — basis for the alternative higher-K strawberry note)

Science in Hydroponics — Comparing Nutrient Solutions for Hydroponic Tomatoes: What the Research Says Science in Hydroponics — Recent Findings in Hydroponic and Soilless Strawberries: A Data-First Look at the Last Decade

(synthesizes Ries et al. 2025 deep-water-culture K trial — no yield benefit raising K above 117 ppm, sometimes reduced fruit size; and Nakro et al. 2023 greenhouse soilless trial — staged K:N ratio 2.6→1.0 raised yield 30% — basis for the substrate-vs-DWC qualifier on Strawberry's K recommendation)

Scientific Reports (Hossain, Shibasaki, Nakao, Nitano & Goto, 2025) — Optimization of Ionic Strength of Nutrient Solution for Enhanced Hydroponic Watermelon Yield and Quality in Greenhouse

(Kagoshima/Rajshahi/Saga Universities; pH maintained at 5.80–6.20, base 'Enshi Shoho' standard solution)

Self Sufficient Culture — pH and EC Reference for Hydroponic Plants and Herbs Shanmugabhavatharani, Swarna Priya, Sankari & Kaleeswari (2022), Madras Agric. J. 109 — Comparative Performance of Mint in Different Hydroponics Systems

Real, species-exact (genus Mentha, cuttings-propagated) NFT trial (Tamil Nadu Agricultural University), comparing horizontal vs. vertical-A NFT geometry across three NPK fertigation rates (40:65:40, 50:75:50, 60:85:60 per hectare — a field-rate unit, not a solution ppm figure, so not convertible to this row's NPK cell without an unstated area-to-volume assumption). Directly states pH 6.5–6.8 and EC ≈2 dS/m "maintained throughout the experimental period." PROMOTES Mint's pH to white/verified at 6.5–6.8, replacing the prior generic Steiner-solution-derived figure (5.5–6.5, per the Juárez-Rosete citation above) with a genuinely mint-specific, hydroponic-maintained pH range. EC NOT applied to override the existing white/verified 1.4 dS/m (Tabatabaie et al. 2007, a genuine EC-response trial that tested and optimized EC as its variable) — this paper's ~2 dS/m was a maintained constant, not itself a tested variable, so the existing more-rigorous source is kept; logged as a real, mint-specific EC data point sitting above the current value for Fred's awareness.

Shershegrows — Best pH and EC Values for Hydroponics (Chart) Shershegrows — Mastering Nutrients: A Simple Guide to pH and EC in Hydroponics Silva, Santos, Dantas Neto, Melo, Matos, Bonou, Silva, Bonfim-Silva, Berilli & Duarte (2023), Agriculture (MDPI) 13(7):1346 — Effect of Electrical Conductivity Levels and Hydrogen Peroxide Priming on Nutrient Solution Uptake by Chives in a Hydroponic System

(Federal University of Campina Grande, Brazil; real NFT hydroponic trial, cv. 'Todo Ano Evergreen — Nebuka', testing electrical conductivity at 1.0, 2.0, 3.0, 4.0, and 5.0 dS/m crossed with five hydrogen peroxide seed-priming concentrations — base nutrient solution prepared per Furlani et al.'s recommendation for leafy vegetables using the commercial Hidrogood Fert compound plus calcium nitrate, giving 75 N, 67.5 P, 210 K, 27.75 Mg, 32.25 S mg/L from the base compound alone, with calcium nitrate added separately; pH held at 6.0 throughout. The trial's own conclusion: "The electrical conductivity of the nutrient solution to obtain the maximum yield of chives in hydroponic cultivation is 1 dS/m" — every measured variable (bulb length, bulb diameter, total fresh mass, nutrient solution use efficiency) declined as EC increased from 1.0 to 5.0 dS/m, with no benefit found above 1.0. Hydrogen peroxide priming alone had no significant effect on any measured outcome. Basis for Chives' verified EC, replacing the prior unverified figure that had been carried over from this calculator's original QP Seedlings design template (yellow/qp-tier, never crop-specific) — NPK and pH are unaffected and remain sourced to the existing Haifa-derived citation elsewhere in this file.

Silva, Soares, Gheyi, Oliveira & Santos (2020), Engenharia Agrícola 40(6):674-683 — Hydroponic Cultivation of Coriander Using Fresh and Brackish Waters with Different Temperatures of the Nutrient Solution

Real, peer-reviewed, species-exact (Coriandrum sativum, cvs. Tabocas and Verdão) NFT hydroponic trial (Federal University of Recôncavo of Bahia) testing nutrient-solution temperature (unheated vs. 30/32°C) and water salinity (fresh vs. brackish). The base recipe is built on "the standard nutrient solution recommended by Furlani et al. (1999) for leafy vegetables" — the SAME source already underlying Cilantro's existing verified NPK (see Luz et al. 2012 above) — but this paper does not restate a full N-P-K composition of its own, only the resulting fresh-water/unheated control ECsol of 2.7 dS/m (Experiment I) and 2.5 dS/m (Experiment II), both at pH ≈6.0. This is a real, directly-measured EC for a Furlani-based cilantro solution notably higher than Cilantro's existing verified 1.6–1.75 EC (itself measured on the same base recipe by Luz et al. 2012) — a genuine discrepancy between two independent measurements of nominally the same reference solution, most likely reflecting different EC meter calibration, water source, or exact salt-dosing rather than a different recipe. pH (≈6.0) is consistent with Cilantro's existing 5.5–6.0 range. Logged as a real, genus/species-exact citation; NOT used to change Cilantro's displayed EC, since it doesn't add a complete independent recipe of its own — only an incidental measured value using a source already on file, with an unresolved discrepancy against that same source's own prior measurement. The paper's actual tested variables (temperature and brackish water) are salinity/thermal-stress findings, not feeding-target data, and are outside this calculator's scope.

Singhal, Gupta & Dubey (2023), Int Res J Biotechnology 14(3):1-6 — Effect of Using Two Nutrient Solutions with Different NPK Ratios on Physical Characteristics and Concentration of Bioactive Compounds in Peas (Pisum sativum)

Real, species-exact (Pisum sativum) NFT hydroponic trial comparing two raw-salt recipes at NPK ratios 2:1:3 (M1) and 6:1:2 (M2), with full salt-by-salt gram/L quantities directly stated (M1: NH4NO3 1.2g, Ca(NO3)2 3.7g, KH2PO4 1.89g, K2SO4 1.32g per liter, plus a common micronutrient mix) and a stated pH 5.5–6.5, TDS 980–1260 ppm. M1 gave better vegetative growth (more leaves/branches); M2 gave higher stress-induced phytochemical content. CHECKED AND DECLINED: converting M1's salts to ppm (using the more plausible Ca(NO3)2·4H2O hydrate, since the anhydrous assumption produces an even less plausible number) gives approximately 859N-430P-1135K ppm — combined with Ca/Mg from the same recipe, the computed total dissolved ion content substantially exceeds the paper's own stated TDS of 980–1260 ppm by a wide margin, indicating either an unstated dilution step between stock and feed strength or an internal inconsistency in the source. Per this file's standing practice of checking computed numbers for plausibility (not just source authenticity), this figure is not applied to Peas' NPK, which remains pink/unsourced. Logged as a real, genus-exact citation only.

Soltanbeigi, Yildiz & Sakartepe (2021), Alinteri Journal of Agriculture Sciences — Effects of Various Nutrient Sources on Growth and Essential Oil Characteristics of Salvia officinalis L. in Greenhouse Salve Regina University Hydroponic Growing Guide (Mitchell, 2022) — Sugar Snap Organic Pea (Pisum sativum)

Real, named, genus-exact student hydroponic-growing guide (Salve Regina University, "MGS2" media-flow system), for Sugar Snap, Sugar Ann, Cascadia Snap, and Sugar Magnolia pea varieties in a clay-pebble media-flow system, target ppm 1250 (range 980–1260), pH 6.5–6.8, using a 1:1.5 ratio of General Hydroponics FloraMicro (5-0-1) to FloraGro (2-1-6). NPK NOT DERIVABLE — REASONING SHARPENED this session (per Fred): the disqualifying rule is about claims of crop-specific performance attributed to a commercial source, not about whether an academic study used a commercial product at all. The prior NPK figure (150N-12P-156K ppm) failed that test for a specific reason: it was computed entirely by looking up General Hydroponics' own published FloraMicro/FloraGro composition percentages and applying the students' stated mixing ratio to them — the number itself is GH's own claimed product composition, not anything independently measured or validated by this report. Compounding that, the report's harvest was never completed ("First Harvest on day: TBA"), so there's no independent crop-performance data here at all to fall back on. Peas' NPK stays unsourced (yellow, `qpNpk` tier) for that reason — genuinely no independently-validated figure exists, not because a commercial product was involved. pH (directly stated, 6.5–6.8) remains white/verified, since it's the report's own recorded target and carries no such provenance problem. PPM-SCALE CAVEAT (added after Fred's question about TDS scales): EC's "1250 ppm TDS" reading is the ONLY cell in the entire calculator expressed as ppm-TDS rather than direct EC (mS/cm) — every other row uses mS/cm, a scale-independent physical unit. TDS-ppm readings are NOT scale-independent: there are three competing hydroponic conductivity-to-ppm conversion factors in active manufacturer use (~500 ppm/mS/cm "NaCl" scale, standard in the US; ~640-650 ppm/mS/cm "European" scale; ~700 ppm/mS/cm "442/KCl" scale, standard in Australia and used by some US/UK brands too) — sources disagree on exactly which region defaults to which scale, which itself underscores how unstandardized this is. This guide (a Rhode Island, USA university report) never states which scale its meter used; the 500 scale is the most probable assumption per US convention but is NOT confirmed. EC stays orange/caveated: a directly-stated number whose real physical meaning depends on an unconfirmed, unstated scale assumption is a genuine caveat, not a clean verified figure. Converting to mS/cm for comparison with any other crop's EC would require picking one of the three scales without source confirmation, so the figure is left as "1250 ppm TDS" (unconverted) and flagged orange rather than white.

Sriti, Máximo-Salgado, Deng, Williamson & Liu (2026), UF/IFAS Extension HS1518 — A Step-by-Step Fertigation Guide for Blackberry Growers in Florida

Real, freshly-published (March 2026) UF/IFAS Extension fertigation guide, field trial at the UF/IFAS Plant Science Research and Education Unit, Citra, FL. Gives a worked example using Dyno Flo 5-2-8 YZ fertilizer targeting a SOIL fertigation concentration of 200 ppm N (5 lb N/acre/week via drip irrigation into field soil) — this is a soil/field fertigation target, not a hydroponic solution concentration, and field rates account for soil buffering and native fertility that a closed hydroponic system does not have, so this number is NOT directly comparable to or used for Blackberry's existing hydroponic-equivalent NPK figure (see Blackberry's Veg-stage note for the full derivation, built from Strik & Bryla 2015 and Strik/Clark/Finn 2012 below). Kept as real, recent, species-specific corroboration that blackberry's N demand is real and substantial, consistent with the existing derivation's direction, without being used to override the actual displayed figure. Also cites Sriti, Williamson, Sargent, Deng & Liu (2024), Agriculture 14(9):1444 ("Principles and Significance of Nitrogen Management for Blackberry Production") — a real, separate, soil/field N-rate review giving 25-45 kg/ha (year 1) to 45-70 kg/ha (subsequent years), same field-rate genre as the figures already used in Blackberry's derivation, and Strik & Vance (2016), Acta Hort. 1133:311-317 ("Leaf Nutrient Concentration in Blackberry") — a real leaf-tissue sufficiency-range standard (diagnostic, not a feeding recipe), same category distinction already applied elsewhere in this file to tissue-analysis papers. None of these three sources changes Blackberry's displayed NPK/EC/pH.

Steel, Antille & Gleadow (2026), Frontiers in Plant Science 16:1731490 — Optimising Plant Growth, Biomass Partitioning, and Nitrogen Use Efficiency in Taro (Colocasia esculenta (L.) Schott)

Real, complete, peer-reviewed, genus-exact (Colocasia esculenta, cv. Bun Long) dedicated concentration-response trial — Monash University/La Trobe University/CSIRO/Harper Adams University, full primary text read directly. Plants grown in a modified Hoagland's Solution at five N concentrations (2.5, 5, 10, 15, 20 mM N as nitrate:ammonium 5:1 mole ratio), with all other nutrients held constant and non-limiting: 6.2mM KCl, 6.2mM CaCl2, 0.25mM MgSO4, 0.125mM KH2PO4, 4µM FeEDTA, plus micros (20µM H3BO3, 46µM MnSO4, 15µM CuSO4, 46µM ZnSO4·7H2O, 26.5µM NH4Mo7O4·4H2O). Corm biomass (the harvested storage organ) was highest at 5 and 10 mM N, with the paper's own stated conclusion: "the optimal N level for maximizing corm biomass without compromising nutritional quality is around 10 mM N" — both higher (15, 20mM) and lower (2.5mM) levels gave inferior corm yield, a genuine bounded optimum from a dedicated dose-response study, not an incidental control-group composition. Converts at 10mM N to roughly 140N-4P-242K ppm, Ca 249, Mg 6 — basis for Taro's verified NPK, replacing the prior generic, unsupported ratio placeholder (5-10-10). Also explicitly states "the optimum soil pH for taro is between 6.0 and 7.0" (citing Deenik et al. 2013) — basis for Taro's verified pH, replacing the prior single-source Howhydroponics figure (5.0–5.5). EC was not stated anywhere in this paper (the solution was characterized by molar N concentration, not EC/TDS) — Taro's EC remains the prior unverified QP Seedlings-sourced placeholder, still yellow.

Steiner (1984), Sixth International Congress on Soilless Culture — The Universal Nutrient Solution

(modified-Steiner ppm table: N-168, P-31, K-273 — basis for Mint's derived NPK)

Strik & Bryla (2015), HortTechnology 25(4):452-459 — Uptake and Partitioning of Nutrients in Blackberry and Raspberry and Evaluating Plant Nutrient Status for Accurate Assessment of Fertilizer Requirements

(Oregon State University/USDA-ARS; review/synthesis of field nutrient-uptake research across both genera — states annual total N accumulation in the aboveground plant ranges 62–110 lb/acre in field-grown red raspberry vs. 33–39 lb/acre in blackberry; also notes blackberry's high yield drives significant K removal specifically in harvested fruit, more so than its primocane leaf-tissue K would suggest — basis for the N-scaling ratio (blackberry:raspberry ≈0.419) used to derive Blackberry's NPK in this calculator from Raspberry's verified hydroponic figures; see Blackberry's Veg-stage note for the full derivation chain. NOT a hydroponic source — this is field/soil agronomy, used here only for the cross-species ratio it provides. ALTERNATE HOST CONFIRMED (Fred-supplied, hero.epa.gov/reference/4605176) — same paper, fuller abstract, adding three details not previously captured here: (1) per-nutrient harvest-removal ranges, both genera similar per ton of fruit: N 11-18, K 10-19, P 2-4, Ca 1-2, Mg 1-4 lb/acre — a real figure, but a removal rate rather than a feed-ppm target, so not usable per Rule 8; (2) the standard late-July/early-August leaf-sampling window is valid for raspberry and floricane-fruiting blackberry, but NOT for primocane-fruiting blackberry, where sampling during the green-fruit stage is recommended instead — a genuinely separate methodological point not covered elsewhere in this file; (3) published K leaf-tissue standards are flagged as running too high for primocane-fruiting raspberry and blackberry specifically, since primocanes are actively fruiting (and pulling K into fruit) at the time leaf samples are taken, making the leaf reading look artificially low relative to standards calibrated on floricane types — a real caveat relevant to interpreting any leaf-tissue K reading on primocane-fruiting blackberry, though it does not itself supply or change any ppm figure here.)

Strik, Clark & Finn (2012), HortScience 47(5):593-598 — Management of Primocane-fruiting Blackberry

(Oregon State University/University of Arkansas/USDA-ARS; real field trial on 'Prime-Jan' and 'Prime-Jim' primocane-fruiting blackberry, Aurora, OR, testing primocane pruning/management systems — states the field fertilization program directly: 55 kg/ha nitrogen (N), 35 kg/ha phosphorus (P), and 66 kg/ha potassium (K) applied each spring, plus an additional 28 kg/ha N at primocane bloom — basis (P:N and K:N ratios only, not absolute values) for Blackberry's derived NPK in this calculator; see Blackberry's Veg-stage note for the full derivation chain)

Stutte (2006), HortScience 41(3):526-530 — Process and Product: Recirculating Hydroponics and Bioactive Compounds in a Controlled Environment

Real, complete primary text (NASA Dynamac Corporation, Kennedy Space Center; CELSS/Bioregenerative Life Support Program). A 418-day recirculating NFT trial growing 'Norland' potato (Solanum tuberosum), explicitly stating: nutrient solution was standard Hoagland's solution, EC controlled near 1.2 dS/m by replenishment, pH controlled to 5.8 ± 0.2 via dilute HNO3 additions. Converts (via the standard 5mM KNO3/5mM Ca(NO3)2/2mM MgSO4/1mM KH2PO4 Hoagland's recipe) to roughly 210N-31P-235K ppm, Ca 200, Mg 49. IMPORTANT CAVEAT: this experiment's actual tested variable was nutrient-solution AGE and bioactive-compound accumulation (a "tuber-inducing factor" that built up in unchanged solution and altered plant morphology), not nutrient concentration optimization — Hoagland's was simply the standard reference medium used throughout, not itself the subject of testing. Basis for Potato's verified EC and pH, and for an NPK figure with reasonable confidence as a real, working, genus-exact hydroponic recipe — but this should not be read as a validated *optimal* potato recipe the way a dedicated concentration-response trial would provide. Table 1 of this paper also lists the full roster of crops grown hydroponically at NASA's Biomass Production Chamber 1988-1996 (bean, carrot, chard, lettuce, onion, peanut, pepper, potato, radish, red beet, rice, soybean, spinach, strawberry, sweetpotato, tomato, wheat) with cultivars and edible parts, for reference.

Tabatabaie, Nazari & Tehranifar (2007), Acta Horticulturae 747:197-201 — Influence of Various Electrical Conductivity Levels on the Growth and Essential Oil Content of Peppermint (Mentha piperita L.) Grown in Hydroponic

DOI 10.17660/ActaHortic.2007.747.22. Real, peer-reviewed, species-exact (Mentha piperita) hydroponic EC-response trial — tested EC 0.7, 1.4, 2.8, and 5.6 dS/m (plus a 5.6+NaCl salinity arm). Fresh weight, overall vegetative growth, and essential-oil balance were all best at EC 1.4 dS/m; higher EC increased oil concentration per unit tissue but reduced total biomass, giving a lower net oil yield. PROMOTES Mint's EC to white/verified at a single value (1.4), replacing the prior generic Steiner-solution-derived range (1.5–2.0 dS/m, per the Juárez-Rosete citation above) with a genuinely mint-specific, growth-outcome-validated target. NPK is sourced separately (see Treadwell et al. 2011 above) — this paper gives no N-P-K feed concentrations, only EC/salinity response.

The Greenery Retail — Suitable pH, TDS, and EC Levels for Specific Vegetables Treadwell, Hochmuth, Hochmuth, Simonne, Sargent, Davis, Laughlin & Berry (2011), HortTechnology 21(2):162-169 — Organic Fertilization Programs for Greenhouse Fresh-cut Basil and Spearmint in a Soilless Media Trough System

DOI 10.21273/HORTTECH.21.2.162. Real, peer-reviewed, UF/IFAS greenhouse trial (Live Oak, FL, 2005–2006), species-exact for spearmint (Mentha spicata — the same species this calculator's Mint row represents) grown in a soilless media trough system. Four NOP-organic fertilizer treatments were compared against a conventional hydroponic nutrient solution control, directly stated as 150 ppm N, 50 ppm P, 200 ppm K — this is the figure used here. PROMOTES Mint's NPK to white/verified, replacing the prior generic Steiner-solution-derived figure (168-31-273, per the Juárez-Rosete citation above) with a directly-stated, species-exact conventional-control recipe from a real trial (as opposed to a derived/converted figure). EC and pH are not affected by this citation — this paper doesn't report EC/pH targets for the conventional control, only the organic-vs-conventional yield/quality comparison.

UC Agriculture & Natural Resources (UC Master Gardener Program) — Artichoke, Pepino Dulce

(light requirements)

Ujong, Naibaho, Ghalamara, Tiwari, Hanon & Tiwari (2025), Sustainable Food Technology 3:54-80 — Duckweed: Exploring Its Farm-to-Fork Potential for Food Production and Biorefineries

(Teagasc Food Research Centre/Technological University Dublin; broad review, not itself a trial, so citation-only rather than a number-changing source. Real corroboration and dose-response detail worth noting: states the ideal wastewater-cultivation conductivity range is 600–1400 µS/cm (= 0.6–1.4 mS/cm), matching this row's white/verified EC figure exactly (independently sourced from Iqbal et al. 2017 above) — a second corroborating reference for the same EC range. Also reports real dose-response pH data (citing Ullah et al. 2023): growth rate peaked at 90 g/m²/day at pH 7, declining to 40 g/m²/day at pH 4, within a stated optimal range of 6.5–8 — consistent with, and additional quantitative support for, this row's existing pH range (already sourced from a dedicated Lemna minor pH-response trial above). NPK: gives dose-response findings (e.g. growth favored at N 345 ppm/P 150 ppm for L. punctata, with growth rates dropping sharply below N 34.5/P 15 ppm) rather than a stated recipe — real and informative but predates this row's 2026-07-11 NPK resolution (Petersen et al. 2022's 14-3-36, per Fred's explicit choice); logged as context only, not applied.

University of Arkansas (Ryan Dickson, Ph.D.) — Managing Nutrient Solutions for Hydroponic Crops University of Florida, UF/IFAS Extension (Ask IFAS) — African Violet

(light requirements; ENH1096/EP360 substrate pH 5.8–6.5, EC <0.8 dS/m for established plants, 15-15-15 or 20-20-20 fertilizer at N 100–125 ppm — basis for African Violet's derived NPK), Banana, Passionfruit (light requirements). Note: OSU Extension HLA-6722 gives a different general greenhouse-hydroponic EC/pH range for African Violet (1.2–1.5 EC, 6.0–7.0 pH) that does not match this species-specific UF/IFAS figure — the UF/IFAS figure is retained since it is specific to African Violet care rather than a general table entry

University of Florida, UF/IFAS Extension — HS796/CV216: Nutrient Solution Formulation for Hydroponic (Perlite, Rockwool, NFT) Tomatoes in Florida (Hochmuth & Hochmuth)

— full 5-stage tomato recipe (70→150N, 50P flat, 120→200K ppm), pH 5.8–6.2; publication explicitly states this program is a suitable base for cucumbers and peppers — basis for Peppers' derived Veg and Fruit NPK

University of Illinois Extension — Sweet Potato, Rhubarb

(light requirements)

University of Minnesota Extension — Blueberry, Currant, Rhubarb

(light requirements)

USDA Agricultural Research Service — Modified Hoagland's Standard Nutrient Recipe

(pH 5.6–6.0; used to derive Garlic's EC/pH via Soufi et al. 2025)

Valdez, Ito, Shinohara & Maruo (2002), Environmental Control in Biology 40(2):167-175 — Effects of Nutrient Solution Levels on the Growth, Yield and Mineral Contents in Hydroponically-Grown Bush Snap Bean

(Chiba University, Japan; real hydroponic trial on bush snap bean cv. Torukatto, rockwool-raised seedlings transferred to Wagner pots with aerated nutrient solution, testing 1/4, 1/2, 1, 1.5, and 2x strength of the standard Enshi-shoho solution, EC 0.6–4.8 dS/m; the paper states the full standard-strength composition directly — NO3-N 16.00, NH4-N 1.33, PO4-P 4.00, K 8.00, Ca 8.00, Mg 4.00 meq/L (Hori 1966) — and found 1/2-strength, N 121-P 62-K 156 ppm at EC 1.2, sufficient and economical for pod yield comparable to higher concentrations — basis for Beans' verified Flower/Fruit NPK and EC)

Veerana, Ketya, Choi & Park (2024), Frontiers in Plant Science 15:1445791 — Non-Thermal Plasma Enhances Growth and Salinity Tolerance of Bok Choy (Brassica rapa subsp. chinensis) in Hydroponic Culture

Real, peer-reviewed, species-exact (Brassica rapa subsp. chinensis) hydroponic trial (Kwangwoon University, Korea) testing non-thermal plasma-gas treatment of standard 1X Hoagland's solution (per Hoagland & Arnon 1950) on bok choy growth and salinity-stress tolerance. Plasma treatment (10 min/week) real, measured outcomes: +80.5% dry weight, +25.6% shoot length, +97.2% root length, increased chlorophyll/soluble protein/N uptake, and improved growth under 20mM NaCl salinity stress versus untreated Hoagland's — a genuinely interesting cultivation-technique finding, but about a water-treatment technology layered onto a standard, unmodified base recipe, not a feeding-target study of its own. NOT used to change Bok Choy's displayed NPK/EC/pH: like the Karantzi banana paper and the Haber marjoram paper above, this source names "1X Hoagland's solution" without restating its own N-P-K-ppm composition (Corrective Lesson #6) — Bok Choy already has a stronger, directly-computed, species-specific verified NPK (Kano et al. 2021, above). Logged as real, on-topic, species-exact corroboration and as a genuinely novel cultivation-technique lead (plasma-treated nutrient solution) that doesn't fit this calculator's NPK/EC/pH fields but may be worth flagging to Fred as a separate area of interest.

Voogt, W. et al. (2014), ISHS Acta Horticulturae 1017 — Development of a Soilless Growing System for Blueberries (Vaccinium corymbosum): Nutrient Demand and Nutrient Solution

(Wageningen UR/BICH; found blueberry K demand much lower than typical greenhouse crops)

Wiser & Blom (2016), American Journal of Plant Sciences 7:1590-1599 — The Effect of Nitrogen and Phosphorus Ratios and Electrical Conductivity on Plant Growth

(University of Guelph, Canada; real hydroponic trial on marigold, sunflower, and tomato cv. Roma in aerated 1-L ceramic pots, testing NO3-/NH4+, NO3-/P, and NH4+/P ratios at a constant EC (~1.2 dS/m), then the same ratios across four ECs (0.6, 1.2, 2.2, 4.0 dS/m); control = 1/2-strength modified Hoagland's solution #2 — found nutrient ratio modification did NOT reliably control plant height as commonly believed by growers; EC level was the more consistent height-control lever, with marigold/sunflower shorter at high EC while tomato trended taller at high EC; full ionic composition table (Ca/Mg/K/NH4/NO3/H2PO4/SO4 in mM) given for all tested ratios — not a feeding-recipe optimization study, so it doesn't change Tomato's existing verified NPK, but it's useful counter-evidence against the "raise NO3:NH4 ratio to control height" assumption sometimes applied to hydroponic tomato and marigold)

Wongsorn (2025), Journal of Science and Agricultural Technology — Effects of Electrical Conductivity of the Nutrient Solution on the Growth of Pepino (Solanum muricatum Aiton) Plants Under Hydroponic Cultivation

(Rajamangala University of Technology Lanna, Thailand; real hydroponic greenhouse trial testing EC 1, 2, 3, 4 mS/cm — confirms Pepino's existing EC range, with lower EC, 1–2 mS/cm, favoring flowering and higher EC, 4 mS/cm, favoring vegetative growth; no NPK breakdown reported, so Pepino's NPK ratio stays as-is)

Yang, Samarakoon & Altland (2025), Frontiers in Plant Science 16:1629432 — Modified Nutrient Management Protocol for Optimum Biomass Production, Nutritional Quality, and Flavor-Related Phytochemical Properties of Hydroponic-Grown Kale (Brassica oleracea)

(Ohio State University Agricultural Technical Institute / USDA-ARS; real NFT hydroponic trial, cv. 'Red Russian', conducted in a greenhouse at the Ohio State Wooster campus — Table 1 gives the full base macronutrient recipe used throughout the 4-week trial: N 129.2, P 48.3, K 183.2, S 52.1, Ca 136.5, Mg 32.7 mg/L, at EC 1.8 dS/m and pH 5.8 — basis for Kale's verified NPK, EC, and pH, replacing a prior generic figure (200-41-280 ppm) that was shared, unsupported, across five unrelated Brassica crops and downgraded to orange/derived earlier in this calculator's audit history. The trial's actual experimental variable — whether substituting calcium nitrate alone for the standard two-part fertilizer mix during the final production week improves yield — found a real 28.5% biomass increase, but that finding describes a single-week end-of-cycle adjustment, not a different baseline recipe, so it is not reflected in the adopted NPK figure above. The paper's introduction separately references an earlier paper, now obtained directly and cited just above this entry (Yang, Samarakoon, Altland & Ling 2024, Agronomy 14:2704), confirming that Collard Greens — same species, Brassica oleracea — shares the identical EC 1.8 recipe given here for Kale, since both crops were grown together sharing reservoirs in that earlier trial.

Yang, Samarakoon, Altland & Ling (2024), Agronomy 14:2704 — Influence of Electrical Conductivity on Plant Growth, Nutritional Quality, and Phytochemical Properties of Kale (Brassica napus) and Collard (Brassica oleracea) Grown Using Hydroponics

(Ohio State University Agricultural Technical Institute / USDA-ARS; real NFT hydroponic trial, cv. 'Red Russian' kale and 'Flash F1' collard grown together, alternately, in the SAME NFT channels sharing the same nutrient reservoirs, double-poly greenhouse at the Ohio State Wooster campus, tested at four EC levels — 1.2, 1.5, 1.8, 2.1 mS/cm. Table 2 gives the full macronutrient recipe at EC 1.8 directly: N 129.2, P 48.3, K 183.2, S 52.1, Ca 136.5, Mg 32.7 mg/L, pH 5.8. **This is the earlier paper (referenced but not independently verified) that the companion 2025 Frontiers Kale paper below cites for Collard's own EC optimum — now obtained directly.** Confirms the Frontiers paper's identical EC 1.8/pH 5.8 recipe (same lab, same system, presumably the same base solution scaled to that trial's EC) and resolves the open cross-reference: because kale and collard shared reservoirs in this trial, the EC 1.8 recipe is genuinely dual-crop-verified, not Kale-by-analogy. Yield response differed by crop — kale's shoot fresh/dry weight and leaf area increased linearly up to the highest EC tested (2.1), while collard's yield plateaued and did not improve further above EC 1.8, making 1.8 collard's genuine yield optimum and 2.1 kale's (consistent with the Frontiers paper's EC 1.8 recipe being used for Kale despite collard's own optimum being identical at that EC level). **Basis for upgrading Collard Greens' NPK from the generic, shared five-Brassica placeholder (175-36-245 ppm) to this genus-exact, dual-verified figure (129-48-183 ppm, EC 1.8, pH 5.8) — promoted to white/verified, removing the npkDerived flag.** Secondary phytochemical findings (vitamin C, anthocyanin, and total phenols decreased with rising EC in both crops; nitrate content rose with EC and approached EU safety thresholds for kale at EC 2.1) are noted as quality-tradeoff context, not reflected in the displayed feeding figures.

Zhang, Wang, Tan, Li, Yu, Li, Liu & Xiong (2025), Technology in Horticulture 5:e034 — Simple, Rapid, Efficient Hydroponic Cultivation Technology on Elevated Racks of Celery

(Nanjing Agricultural University / Guizhou Academy of Agricultural Sciences / Sichuan Agricultural University, China; real, complete, genus-exact NFT pipeline recipe for celery, Apium graveolens, given in full in Table 1 — modified from Hoagland's solution: calcium nitrate 950, potassium nitrate 810, magnesium sulfate 500, ammonium dihydrogen phosphate 155 mg/L, plus a full micronutrient package (Fe-EDTA, boric acid, manganese/zinc/copper sulfate, sodium or ammonium molybdate) — converts to roughly 244N-42P-313K ppm, Ca 161, Mg 49. Basis for Celery's verified NPK, replacing the prior generic, unsupported figure (175-36-245 ppm) that had been shared across an unrelated cluster of brassica crops. EC/pH: the paper gives two different stage-specific ranges that are internally inconsistent with each other — "around 2.0 mS/cm" during the seedling-recovery period immediately post-transplant (pH 6.0–6.5), then states the nutrient concentration was "appropriately increased" during the subsequent peak-growth period while simultaneously giving a LOWER stated EC range of 1.0–1.5 mS/cm (pH 5.7–7.0) for that later stage — these two claims (concentration increased, EC decreased) cannot both be literally true and are most likely a translation or drafting inconsistency in the original paper, since several listed values throughout this article show signs of imprecise English rendering. Both EC ranges are shown here as a combined 1.0–2.0 span rather than silently picking one, to honestly reflect that the source itself is ambiguous on this point.

陈昆, 刘世琦, 张自坤, 张涛, 孟凡鲁 / Chen Kun, Liu Shi-qi, Zhang Zi-kun, Zhang Tao, Meng Fan-lu (2011), 园艺学报 (Acta Horticulturae Sinica) 38(3):556-562 — 钾素对水培大蒜生理和品质的影响 / Effects of Potassium on the Physiology and Quality of Hydroponically-Grown Garlic

(real solution-culture garlic trial, cv. 'Jinxiang White-skin Garlic'; K+ tested at 0, 3.0, 6.0, 9.0, 12.0 mmol/L; growth and quality measures peaked at 9.0 mmol/L K+ (≈352 ppm), declining at 12.0 — found via a Chinese-language research pass; companion N and P levels held constant in the trial were not accessible in retrievable text, so this confirms a real K target without completing Garlic's NPK triplet)

陈昆, 刘世琦, 张自坤, 张涛, 孟凡鲁 / Chen Kun, Liu Shi-qi, Zhang Zi-kun, Zhang Tao, Meng Fan-lu (2011), 植物营养与肥料学报 (Journal of Plant Nutrition and Fertilizer Science) 17(2):506-512 — 钾素营养对大蒜生长、光合特性及品质的影响 / Effects of Potassium Nutrition on Garlic Growth, Photosynthetic Characteristics and Quality

(companion solution-culture garlic K trial, same author group, same 0-12.0 mmol/L K+ range — seedling-stage growth and photosynthetic measures peaked at 6.0 mmol/L K+ (≈235 ppm); same limitation as the Acta Horticulturae Sinica paper above, N and P baseline not retrievable)

Extrapolated estimate — ratio-only guess, or derived from a related crop/general principle backed by real academic or extension data

Industry-sourced, not academically verified

Howhydroponics — EC, pH, and PPM Reading Chart for Hydroponics

QP Seedlings — Optimal NPK Ratios, Electrical Conductivity (EC) and pH Levels for Growing Vegetables (initial design inspiration)

Please forward any relevant academic studies to Fred Thompson (see buttons at the bottom of the page.)

Cornell CEA Program (Ronzoni & Mattson, 2020) — A Guide to Home Hydroponics for Leafy Greens

— home-scale companion to the commercial Lettuce/Spinach handbooks above; gives a "Modified Sonneveld's Solution for leafy greens" target table (150N-31P-210K-90Ca-24Mg-32S ppm) used as its DWC lettuce-growing baseline; context/corroboration only, no row in this calculator matches "leafy greens" generically

Cornell University (Helmer, Timmons & Mattson, 2022) — CEA Strawberry Runner Propagation for Deep Water Culture

— describes a DWC bench for rooting 'Albion' and 'Cabrillo' runners off soil-grown mother plants (fed Jack's Professional All Purpose LX 21-5-20 at 150 ppm N) before transfer into hydroponic production systems; propagation-stage methods reference only, not a feeding recipe for mature strawberry plants — does not change Strawberry's existing verified NPK

Cornell University, Department of Horticulture, Publication 23 (Koester & Pritts, 2003) — Greenhouse Raspberry Production Guide

Real, named, methodologically complete Cornell extension guide for container-grown greenhouse raspberry (genuinely soilless per this file's substrate definition — 2 parts peat : 2 parts vermiculite : 1 part sand, no garden soil). Gives a full worked fertigation example: two stock solutions (615g calcium nitrate + 130g ammonium nitrate per 38L; 1230g Peter's Hydrosol 5-11-26 per 38L) diluted 1:50 each and combined, yielding a complete, independently-calculable N-P-K triplet of roughly 100N-31P-140K ppm during vegetative growth (EC ≤1.5 mS/cm, solution pH 6.5), with the rate halved to ~50ppm N once flowering begins to avoid excess vegetative growth and soft fruit. Genuinely different growing system from the verified Bazangeya et al. 2025 source already used for Raspberry (outdoor first-season container culture moved into an unheated-then-heated greenhouse, vs. Bazangeya's indoor vertical-farm trial) and the two sets of numbers disagree substantially, especially on P (Cornell ~31 ppm vs. Bazangeya's Bloom/Fruit-stage P of 104–114 ppm — roughly a third). Per direct instruction, kept as a real, valid, corroborating citation — Raspberry's displayed NPK/EC/pH is unchanged.

Cruz Crespo, Can Chulim, Loera Rosales, Aguilar Benítez, Pineda Pineda & Bugarín Montoya (2017), Rev. Mex. Cienc. Agríc. 8(2):355 — N-P-K Extraction in Coriandrum sativum 'Pakistan' (Steiner Solution, Substrate Culture)

Real, species-exact, dedicated Steiner-solution concentration trial on Cilantro (Universidad Autónoma de Nayarit, tezontle substrate) testing four osmotic potentials: 0.018, 0.036, 0.054, and 0.072 MPa. Fred obtained and hand-transcribed Cuadro 1 (the ppm/meq table, embedded as an image and otherwise unreadable): at the paper's own recommended 0.054 MPa level (best commercial height and fresh/dry biomass, from transplant through 50 ddt) — NO3⁻ 9, H2PO4⁻ 0.75, SO4²⁻ 5.25, Ca²⁺ 6.75, Mg²⁺ 3, K⁺ 5.25 meq/L, CE (=EC, Spanish abbreviation) 1.52 dS/m, pH 5.5. Converts to N126-P23-K205 ppm, Ca 135, Mg 36, S 84. Cross-checked against Steiner's (1984) published 100%-strength reference ratio (NO3⁻:H2PO4⁻:SO4²⁻ = 12:1:7 meq/L; Ca²⁺:Mg²⁺:K⁺ = 9:4:7 meq/L) — this trial's 0.054 MPa row matches that ratio exactly, just scaled to 15 of 20 total meq/L (75% Steiner strength), confirming the treatments here are pure strength-dilutions of the fixed classic Steiner ratio, not an independently-optimized N:P:K ratio for cilantro. This explains why its N (126) and P (23) sit well below Cilantro's existing verified figure (204-40-191, Furlani-lineage) despite K (205) and EC (1.52) landing close (191, 1.6–1.75) — Steiner's universal ratio is inherently lower in both N and P share than a Furlani/Hoagland-style leafy-green recipe by design, not because this trial found cilantro needs less of either. A real, dedicated, outcome-validated confirmation that Steiner's solution at 75% strength works well for cilantro, logged as a legitimate alternate formula family rather than a competing "which number is right" conflict — Cilantro's displayed NPK remains orange/derived (Furlani-lineage), unchanged.

Curci, Carrozzo, Pecatelli, Semeraro, Tafuro, Lenucci & De Caroli (2026), Plants 15(6):974 — Environmental and Cultivation Effects on Growth and Phytochemical Profiles of Chicory in Soil, Hydroponics, and Aquaponics

Real, peer-reviewed, species-exact (Cichorium intybus, cv. 'Otrantina', University of Salento) floating-raft hydroponic trial, and — unlike the similarly-Advanced-Nutrients-based citation above — this one DOES give a usable concentration figure directly in mmol/L: nitrate 2.26, ammonium 0.59, urea 1.83, phosphate 0.42, sulfate 0.50, potassium 1.70, calcium 0.86, magnesium 0.10 (plus Fe/Mn/B micros), pH held stable at 6.5 throughout. Converts to roughly 91N-13P-67K ppm (counting urea-N) or ~40N-13P-67K (nitrate+ammonium only, excluding urea-N) — a REAL, directly-stated, complete recipe, but a FOURTH disagreeing figure for the standing Chicory NPK conflict, notably lower on all three macronutrients than the existing MISR/Alaswad (162-25-182), Oliveira et al. 2023 (190-81-215), and Andriolo et al. 2008 (224-47-390) figures. Not applied — logged alongside the other three for Fred's eventual choice among now four real, mutually-disagreeing sources.

Curci, Vásquez-Ibarra, Arencibia, Braglia, Canini, Lenucci & De Caroli (2025), Cleaner Environmental Systems 20 — Life Cycle Assessment of Chicory Production in Soil-Based, Hydroponic, and Decoupled Aquaponic Systems

Real chicory life-cycle environmental-impact study, comparing soil, hydroponic, and decoupled aquaponic production. The hydroponic system's nutrient solution is described using the commercial "Advanced Nutrients pH Perfect Grow/Micro/Bloom" product line — academic usage of this product is treated as legitimate evidence even though Advanced Nutrients itself is denied from this file's approved-industry-source roster (the roster constraint is about citing the company's OWN marketing claims, not about disqualifying independent academic studies that happen to use their product). However, the composition is reported as cumulative raw salt input MASSES per functional unit (per plant, over the full growth cycle) — e.g. kg of monoammonium phosphate, monopotassium phosphate, potassium nitrate, potassium sulphate, urea, and calcium nitrate per plant — not as a solution concentration in ppm. Converting this to ppm would require knowing the replenishment/dilution schedule over the cycle, which the paper does not give; the 18L tank volume stated is the system's total solution volume, not the basis for a concentration calculation from cumulative inputs. Not used for any NPK/EC/pH value — Chicory is already verified from the MISR/Alaswad magnetized-water trial (see below), which gives a genuine concentration-based figure. Kept here as a real, confirmed source documenting an actual commercial hydroponic chicory recipe, in case a future session finds the missing dilution-schedule detail (e.g. via a different access route to the supplementary materials) that would make conversion possible.

Gomes da Silva, Alves, Soares, Gheyi & Bione (2020), Advances in Horticultural Science 34(3):243-253 — Growth, Production and Water Use Efficiency of Chicory (Cichorium endivia L.) in Hydroponic Systems Using Brackish Waters

(Universidade Federal do Recôncavo da Bahia; despite the paper's title, the species tested is true endive, cv. Gigante Barbarella, not chicory; tested ECsol 2.57, 3.43, 4.75 dS/m in DFT and 2.57 dS/m in NFT, built on the same generic Furlani 1999 leafy-vegetable base solution as the related Brazilian salt-stress papers on Okra, Chives, Zucchini and Watercress already cited elsewhere — confirms but does not replace Endive's existing derived EC/pH, since 2.57 dS/m is the lowest of an imposed salinity gradient on a generic base, not a crop-specific recommended target)

Gomes, Arruda, Rosário, Andrade, Mello & Santos (2023), Horticultura Brasileira 41:e2554 — Amazon Chicory: Growing at Full Sunlight or Under Shade?

Real field trial (randomized block, 4 treatments x 5 replicates: black 30/50/70% shading screens vs. full sunlight) testing shading levels on "Amazon chicory" — IMPORTANT NAME COLLISION: despite the common name, this is Eryngium foetidum (a.k.a. chicória-do-Pará, culantro/spiny coriander, family Apiaceae), NOT Cichorium, the genus behind this calculator's existing Chicory row. No relation to that row whatsoever; this calculator has no Eryngium/culantro row to apply this to. The study itself found no significant difference between any shading level (including full sun) for any evaluated vegetative/production trait — the plant tolerates a wide range of light conditions equally well. Soil-grown, not hydroponic. A real, checked source — kept here as considered-and-declined rather than no-relevant-information, in case an Eryngium/culantro row is ever added.

González-García, Rodríguez-Mendoza, Sánchez-García, Osorio-Rosales, Trejo-Téllez, Alcántar-González & Sandoval-Villa (2009), Acta Horticulturae 843:123-128 — Ammonium/Nitrate Ratios in Hydroponic Production of Aromatic Herbs

(Colegio de Postgraduados, Mexico; real drip-irrigated hydroponic trial on chives, basil, and dill in a 60:40 volcanic-rock/coconut-fiber substrate, testing 4 NH4+/NO3- ratios — 0/100, 20/80, 40/60, 100/0 — of a modified Steiner solution; Table 1 gives the full ionic composition (Ca/Mg/K/NH4/NO3/H2PO4/SO4/Cl in molc/m3) for each ratio — chives grew best (height, leaf area, biomass) at 0/100 (pure nitrate); basil grew best at 20/80; dill showed NO significant differences among any ratio, so any of the four (including 0/100, which converts to roughly 168N-31P-156K-180Ca-85Mg-112S ppm) is usable for dill. This calculator has no Chives or Dill row, so this is context/corroboration only — but it is a genuine, complete, dill-specific (and chives-specific) hydroponic nutrient composition if either crop is added later)

Guerrero-Lagunes, Ruiz-Posadas, Rodríguez-Mendoza, Soto-Hernández & Castillo-Morales (2011), Revista Chapingo Serie Horticultura 17(2):141-149 — Effect of Hydroponic Thyme Cultivation on Essential Oil Quality and Yield

Real, peer-reviewed, species-exact (Thymus vulgaris) greenhouse open-hydroponic trial (Colegio de Postgraduados, Mexico) — tezontle substrate, drip-fed Steiner Universal Solution at 100% (S1) or 50% (S2) strength, three sowing densities, pH held constant at 5.5 throughout (not itself the tested variable). Real findings: fresh weight up to 219.68 g/plant and dry weight extrapolating to 54.27 t/ha/year at the best treatment (S1, 28 plants/m²); essential oil concentration 11.00–14.72 mg/g dry matter (thymol the dominant component at 23.3%); no statistical difference in fresh/dry weight between 100% and 50% Steiner strength, i.e. thyme reached full growth on half-strength nutrient solution. Real corroboration of the LOW END of Thyme's existing pH range (5.5–7.0, derived) — a genuine working value for this species, though pH was a held-constant condition here, not an optimized target. NPK not usable: the paper names "Steiner Universal Solution" (citing Steiner 1984) without restating its own elemental composition in ppm — same named-formula-without-numbers gap as other citations in this file. Not applied to Thyme's displayed NPK/EC (Udagawa 1995's dedicated EC-optimization trial remains the stronger source for EC).

Haifa Group — Fertilization of Courgette in Greenhouses

("Nutrition database for courgette (squash)" rockwool table — EC 2.2 mS/cm, N-NH4 17.3 + N-NO3 223.9 = 241 ppm total N, K 283.5 ppm, H2PO4 121.3 ppm (≈39 ppm elemental P), Ca 145.4 ppm, Mg 48.6 ppm, sourced to the same Straver 1994 / de Kreij-Sonneveld-Warmenhoven-Straver 1992 Dutch glasshouse standards — WAS the basis for Squash's verified Fruit-stage NPK and EC until this session, when it was displaced by Pacheco et al. 2023's outcome-validated zucchini figure (see Squash's Fruit-stage note and the Pacheco citation below) — kept here as a real, valid industry recommendation and corroborating reference, not deleted; the page's staged fertigation kg/ha table also confirms the Veg/Flower K-demand timing already shown, though that table is soil-based and not directly convertible to ppm)

Hicks (1932), Ohio Journal of Science 32(3):237-244 — Ranges of pH Tolerance of the Lemnaceae

Real, classic, dedicated pH-tolerance study across seven Lemnaceae species (Ohio State University) — 660+ hydrogen-ion determinations via wild-population surveys (36 Ohio counties), greenhouse cultures, and controlled Clark-buffer series (pH 1.2–10). For Lemna minor specifically (the species this row is genus-generic for): good growth pH 5.4–6.8, fair growth 5.0–5.4 and 6.8–7.4, poor growth 4.5–5.0 and 7.4–7.8, died at pH 4 or below and pH 8 or above; summary conclusion states abundant growth from pH 5.1–6.7. This is a real, controlled, species-exact finding that PARTLY DISAGREES with Duckweed's currently-displayed "6.0–7.0 (peak at pH 7)" figure — Hicks' own data places pH 7 in the "fair," already-declining band, with the true optimum centered lower (roughly 5.4–6.8) rather than peaking at 7. Not applied — kept as a real, dedicated conflicting data point. PER FRED'S EXPLICIT CHOICE (2026-07-11), the pH conflict was RESOLVED in favor of the existing 6.0–7.0 (peak at pH 7) figure, now promoted to white/verified over Hicks' lower 5.4–6.8 optimum and Akyüz & Ersus 2024's 7.22 (see that citation elsewhere in this file).

ISHS Acta Horticulturae 358 (Tongaram, Schrevens & De Rijck, 1994) — The Optimization of the Composition of the Nutrient Solution for Hydroponics Leek Cropping

(K.U. Leuven/Sukhothai Thammathirat Open University; real NFT simplex-lattice mixture-design trial on leek cv. Snowstar — found high potassium AND calcium together (44% K / 44% Ca / 12% Mg of total cations) gave the best yield and quality, with K-Ca and K-Mg interacting antagonistically; for anions, 69% nitrate / 9% dihydrogenphosphate / 22% sulfate (allowing some nitrate to be replaced by sulfate at low, constant phosphate) performed best — directly supports the cation-balance note already on file for Allium crops (K-Ca-Mg management, not just NPK ratios); no row in this calculator currently covers leek)

ISHS Acta Horticulturae 396 (Udagawa, 1995) — Some Responses of Dill (Anethum graveolens) and Thyme (Thymus vulgaris), Grown in Hydroponic, to the Concentration of Nutrient Solution

(Chiba Pref. Agr. Exp. Sta., Japan; real NFT trial, three EC levels — 1.2, 2.4, 3.6 mS/cm; max fresh/dry yield at 3.6 mS/cm for both herbs, but highest essential-oil content at 2.4 mS/cm for dill and 3.6 mS/cm for thyme — N:P:K:Ca:Mg ABSORPTION RATES (uptake, not solution composition — Rule 8 applies, not usable as a feed recipe) reported as 15:2:10:3:2 (dill) and 30:5:10:6:4 (thyme); the abstract also references full solution-strength composition at 3.6 mS/cm (NO3-N 31/Ca 6 me/L etc. for dill) but the complete P/K/Mg figures are behind the ISHS/Acta Hortic paywall — full text not obtained this session. Basis for Dill's and Thyme's white/verified EC (3.6 mS/cm, this species-exact optimization trial); does not resolve either crop's NPK)

ISHS Acta Horticulturae 548 (Ikeda, Tan, Ao & Oda, 2001) — Effects of Soilless Medium on the Growth and Fruit Yield of Tomatoes Supplied with Urea and/or Nitrate

(Osaka Prefecture University; real comparison of rockwool, sand, peatmoss, bagasse, and NFT, each fed urea, urea+nitrate, or nitrate as sole N source at a fixed 112 ppm total N — not a nitrogen-source-blind NPK recipe, so it doesn't change Tomato's existing verified figures, but it is a directly relevant finding for nitrogen FORM: urea-fed plants in NFT (no solid substrate) grew slower than in inorganic media and accumulated leaf urea-N rather than converting it, while urea performed comparably to nitrate in well-aerated inorganic media (rockwool, sand) because nitrification was active there; organic media (peatmoss, bagasse) suffered NH4+ toxicity under urea feeding since nitrification was suppressed — relevant context if Masterblend's own nitrogen form (the 4-18-38 formula uses nitrate, not urea) is ever questioned, and a caution against using urea-based feeds in pure NFT/DWC setups specifically)

ISHS Acta Horticulturae 644 (Colla, Fanasca, Molle & Saccardo, 2004) — Use of Hydroponic Culture to Assess the Mineral Nutrition of Zucchini Squash

(Università degli Studi della Tuscia, Italy; Systematic Variations method, perlite substrate, drip-fed without recirculation — 16-treatment factorial across 8 anion/cation ratio variants × 2 total concentrations (0.5 and 1.0 eq/plant) — found NO3 most influential anion (highest yield with high-nitrate proportion, lowest with high-sulfate/phosphate/chloride), and the optimal 8-nutrient proportion of total nutrition computed at NO3 29.6% / SO4 4.3% / PO4 4.3% / Cl 5.1% / K 17.1% / Ca 16.8% / Mg 16.3% / Na 6.5%, optimal total dose 2.51±0.20 eq/plant — a proportions/ratio study, not an absolute ppm recipe, so it doesn't convert directly to this calculator's NPK format; corroborates the existing K-heavy, Ca/Mg-supported approach already used for Squash)

Klaros Tarım — Nutrition Recipes (Beslenme Programları), "HydroBuddy General Berries" entry

Real HydroBuddy software default-database recipe, republished on Klaros Tarım's nutrition-recipes page and explicitly earmarked there "use for raspberry" (Fred's selection from several recipe options on that page, supplied 2026-07-04). States pH 5.5–6.5, EC 2.0–2.5 mS/cm, and a complete elemental ppm table: N 207, P 55, K 289, Ca 38, Mg 155, S 51, plus micros. This is a single-stage software-default recipe, not a tested/validated hydroponic-raspberry trial, and disagrees substantially with Raspberry's existing verified, stage-specific, outcome-tested Bazangeya et al. 2025 figures (particularly P: 55 ppm here vs. 61–114 ppm across Bazangeya's three stages, and Ca: 38 ppm here vs. no Ca reported by Bazangeya at all). Kept as a real, named corroborating/conflicting citation; not applied — Raspberry's displayed NPK/EC/pH remains the Bazangeya-sourced figures.

Klaros Tarım — Soilless Raspberry (Turkish: Ahududu)

Real, dedicated, industry-published staged raspberry guidance (page text supplied by Fred, 2026-07-04; NOTE — "ahududu" is Turkish for raspberry, not strawberry, and the page's own body text explicitly says "Raspberry nutrient needs vary by growth stage," confirming this is Raspberry despite an initial mislabel when the content was supplied). States: Veg-stage (cane growth) EC 1.5–1.8 mS/cm, N 100 ppm; Flowering/fruiting EC 1.8–2.5 mS/cm, N 50 ppm (P and K described only as "high," no ppm given); pH 5.8–6.2. This conflicts with Raspberry's existing verified EC (1.2–1.7 across stages, from Bazangeya et al. 2025's real outcome-tested indoor hydroponic trial) and pH (5.5–6.5) — industry general guidance vs. a real, dedicated, yield-validated academic trial for the same species. Per this file's standing practice for real-vs-already-verified conflicts, kept as a corroborating citation rather than applied; Raspberry's displayed figures are unchanged.

Kumar & Saini (2020), IntechOpen — Nutrients for Hydroponic Systems in Fruit Crops

(YS Parmar University of Horticulture and Forestry, India; broad review chapter on hydroponic fruit crops — checked specifically for Pineapple data given its one explicit mention: "Solution was also used in pineapple cv. Perola produced through micropropagation in hydroponics system." This refers to MICROPROPAGATION — sterile tissue-culture plantlet production, not mature fruiting-plant cultivation — and the chapter gives no concentration data specific to that pineapple work; its only other pineapple reference is that the generic "Hoagland and Arnon nutrient solution has been used for the production of seedlings of guava and pineapple," i.e. the same unmodified generic Hoagland's formula already excluded from white-tier status elsewhere in this file per Rule 2, not a pineapple-specific recipe. UPDATE (2026-07-04): Pineapple's pH is NO LONGER an exhausted dead end — see Schappelle (1940) below, a real academic water-culture study giving a genuine tested pH optimum. Pineapple's NPK also updated — see Schappelle's complete full-nutrient formula below, which replaced the Ma et al. 2026 research-isolation figure (that figure's known flaws — 4ppm Ca, inverted P:K — are discussed in that citation's note, retained below for the record).

Le, Nguyen, Pham & Nguyen (2025), Horticultural Science (Prague) 52(4):333-341 — Effects of Nutrient Solutions on Growth, Yield and Quality of Yardlong Bean Plant (Vigna unguiculata subsp. sesquipedalis L.) Grown in a Hydroponic System

Real, complete primary text (Hanoi National University of Education, Vietnam) — full PDF read directly. Genus Vigna, NOT Phaseolus — yardlong bean is a different genus from this calculator's existing Beans row (Phaseolus vulgaris, common/snap bean). Static hydroponic system (15L plastic boxes), compressed coconut coir pellets in net pots, pH held 6.0–6.5. Table 1 gives the complete composition of all three tested solutions in ppm: Hoagland (N 99.4, P 30.1, K 117.2, Ca 92.1, Mg 24.2, B 2.5, Mn 2.5, Zn 0.2, Mo 0.2, Cu 0.1, Fe 5.6, S 35.4), Knop (N 117.1, P 32.5, K 133.6, Ca 138.9, Mg 28.8, Fe 1.03, S 38.1 — only 6 elements, no micronutrients), and the commercial product Hydro Umat F (N 171.3, P 33.9, K 273.8, Ca 160.7, Mg 50.0, B 0.5, Mn 1.0, Zn 0.9, Mo 0.6, Cu 0.7, Fe 3.0, S 66.5). Hydro Umat F gave the best results on every measured growth, yield, and quality parameter (105.4-day lifespan, 20.81 pods/plant, 417.45 g pod weight/plant, highest vitamin C/protein/sugar content) despite NOT having the highest individual NPK values relative to Knop on a per-element basis — the paper attributes this to its complete micronutrient package (which Knop lacks) rather than raw NPK strength. Hydro Umat F is also independently confirmed as a real, widely-used commercial Vietnamese hydroponic product in separate published trials on strawberry, gerbera, and impatiens (Thuy et al. 2024 and others), corroborating its genuine commercial status rather than being a one-off lab-only mix. BASIS for the new "Beans, Yardlong" row added to this calculator: NPK taken directly from the Hydro Umat F composition (171-34-274 ppm), pH from the paper's stated 6.0–6.5 range — both white/verified. EC was NOT stated anywhere in the source (only ppm composition given, no EC/TDS meter reading reported) — the displayed EC (1.1–1.5) is a CALCULATED ESTIMATE derived by summing all stated macro+micronutrient ppm (762.9 total) and applying the standard 500/700-scale TDS-to-EC conversion, not a directly-measured or source-stated figure — kept orange/derived to reflect that distinction honestly. A deep separate search for other hydroponic yardlong bean literature found nothing else usable — all other located sources were soil/field fertilizer trials, organic-fertilizer comparisons, breeding/genotype studies, or phytochemistry papers with no hydroponic concentration data.

Ma, Liu, Zhao, Liu, Song, Shi, Li & Shi (2026), Frontiers in Plant Science 16:1754688 — Increasing the Nitrate-to-Ammonium Ratio Improved Plant Growth and Nitrogen Uptake in Pineapple Seedlings

(Chinese Academy of Tropical Agricultural Sciences; real, species-exact (Ananas comosus cv. Comte de Paris) hydroponic trial testing five NO3-:NH4+ ratios — 0:100, 30:70, 50:50, 70:30, 100:0 — at a FIXED total nitrogen of 4 mM. Found 70:30 gave the best overall outcome: highest total root length/surface area, highest NO3- uptake rate, +61.10% leaf area, +24.40% leaf dry matter, +19.49% N accumulation, and +21.62% C accumulation versus pure-ammonium (0:100). The base solution (held constant across all five ratio treatments, with only the NO3-:NH4+ split varying) is directly stated: 1.0 mM KH2PO4, 2.0 mM K2SO4, 2.0 mM MgSO4·7H2O, 0.1 mM CaCl2·2H2O, pH 5.5±0.1. Converting to elemental ppm: 4 mM N = 56 ppm N; 1.0 mM KH2PO4 = 31 ppm P; K from 1.0 mM KH2PO4 + 2.0 mM K2SO4 = 5.0 mM K = 195 ppm K — basis for Pineapple's NPK (56-31-195), replacing the prior generic, derived placeholder (68-136-136), but KEPT IN THE SAME ORANGE/DERIVED TIER rather than promoted to white/verified: this is a research-isolation design (fixed low total N, deliberately minimal CaCl2 at just 4 ppm Ca, to cleanly separate the NO3-:NH4+ ratio's own effect from confounding extra Ca that a more nitrate-heavy commercial Ca(NO3)2-based recipe would otherwise introduce) — not an agronomic feeding program tuned for mature fruit-bearing pineapple. Ca at 4 ppm and the inverted P:K ratio are real findings from real chemistry, but both sit well outside the range expected of a genuine feeding target, which is exactly the situation the orange/derived flag exists to mark — a grower following this recipe long-term would likely want to supplement Ca well beyond what this trial used. EC was not measured or reported in this paper (mM concentrations and pH only) — Pineapple's existing EC (2.0–2.4, Howhydroponics-sourced) is retained unchanged, since no academic EC source exists for this crop.

MDPI Agriculture (Ferreira da Silva et al., 2023) — Effect of Electrical Conductivity Levels and Hydrogen Peroxide Priming on Nutrient Solution Uptake by Chives in a Hydroponic System

(UFCG, Brazil; lowest-stress/control treatment used Furlani-recommended leafy-vegetable solution via the commercial Hidrogood Fert® compound at EC 1.0 dS/m with pH held at 6.0 throughout; the 1.0 dS/m figure is the lowest of an imposed 1–5 dS/m salinity-stress gradient, not a recommended target EC, so this confirms but does not replace Chives' existing QP Seedlings-sourced EC/pH)

Oliveira, Dantas, Ramos, Oliveira, Pinto, Oliveira, Costa, Oliveira, Góis & Dias (2025), Revista Brasileira de Engenharia Agrícola e Ambiental — Endive Production Under Different Hydroponic Systems and Electrical Conductivities of the Nutrient Solution

(Universidade Federal Rural do Semi-Árido, Brazil; real, true Cichorium endivia, species-exact; tested EC 1.6 vs. 2.9 dS/m across NFT, semi-hydroponic, and DFT systems — found semi-hydroponic gave the best development regardless of EC, and recommends EC 1.6 dS/m for SH/DFT systems or 2.9 dS/m specifically for NFT; this is a genuine optimized-target study, not a salt-stress gradient, which corroborates but doesn't replace Endive's existing 1.0–1.8 derived EC range since the recommendation is system-dependent and the calculator doesn't track hydroponic system per crop — left as a corroborating citation pending a clearer single-system match)

Pluda, Rabinowitch & Kafkafi (1993), Journal of the American Society for Horticultural Science 118(1):86-91 — Pepino Dulce Quality Characteristics Respond to Nitrogen Nutrition and Salinity

(Hebrew University of Jerusalem; real hydroponic fertigation trial on three pepino selections testing N-NO3 at 3, 6, or 12 mmol/L — 6 mmol/L (84 ppm N) gave heavier yield and larger fruit than 3 mmol/L, with no further benefit at 12 mmol/L; the study did not test P or K, so this confirms a real optimal N figure without completing Pepino's NPK triplet)

Qiu, Xu, Gaudreau, Gosselin, Gauthier, Van Sterthem & Desjardins (2016), Acta Horticulturae 1133:195-199 — Yield Improvement of Red Raspberry by Soilless Cultivation with Two Propagation Methods Under Northern Canadian Climate

(Université Laval, Canada/Les Fraises de l'Île d'Orléans — real two-year soilless container trial, cv. 'Jeanne d'Orléans', comparing bare-root vs. root-cutting propagation and soil vs. soilless (peat-compost substrate, 4–10L pots) cultivation. Soilless cultivation significantly increased primocane height/diameter and improved marketable fruit yield 1.6–1.7× over soil cultivation, with no significant difference in yield between the two propagation methods — real, genus-exact, corroborating evidence that soilless culture itself benefits raspberry yield. The paper states only that "the same fertigation solution... was used for all treatments" without ever disclosing its N-P-K composition, EC, or pH anywhere in the text — not usable as a number source. Different paper from the Qiu et al. 2017 EJHS citation already used for Raspberry's EC (different cultivar, different question — propagation/substrate comparison rather than EC regime), so added as a separate, additional corroborating citation rather than a duplicate. Does not change Raspberry's existing verified NPK or extrapolated EC/pH.

Revista Caatinga (Cardoso, Sediyama, Poltronieri, Fonseca & Neves, 2017) — Effect of Concentration and N:K Ratio in Nutrient Solution for Hydroponic Production of Cucumber

(Universidade Federal de Viçosa; NFT system; N:K ratios of 1:2.0–1:3.0 w/w gave highest yield in fruiting phase — noted as a discrepancy against Cucumber's Sonneveld-based Fruit-stage ratio)

Rouphael & Colla (2005), Scientia Horticulturae 105:177-195 — Growth, Yield, Fruit Quality and Nutrient Uptake of Hydroponically Cultivated Zucchini Squash as Affected by Irrigation Systems and Growing Seasons

PREVIOUSLY PAYWALLED, now obtained and read in full (user-supplied). Companion paper to Rouphael & Colla (2009) above, same lab (Tuscia University, Viterbo, Italy), same cultivar (Afrodite), same closed-loop peat-pumice pot culture system — confirms the IDENTICAL base nutrient solution already cited from the 2009 paper (NO3-N 173.7, P 37.1, K 195.5, Ca 136.2, Mg 55.9, S 25.6 mg/L, EC kept 1.8–2.4 dS/m, pH 5.8–6.2), so this paper does NOT add a different NPK/EC/pH figure — it is corroborating, not a separate data point. What this paper genuinely adds, not present in the 2009 paper: a real comparison of DRIP-IRRIGATION vs. SUBIRRIGATION across two growing seasons (spring-summer vs. summer-fall). Found drip-irrigation gave 18% higher total/marketable yield than subirrigation specifically in the spring-summer season (due to salt accumulation in the substrate's upper layer under subirrigation during hot, high-evaporation conditions), with no significant yield difference between the two irrigation methods in the cooler summer-fall season; subirrigation gave measurably higher fruit quality (dry matter, glucose, fructose) despite the spring-summer yield penalty. Total nutrient uptake (N, P, K, Ca, Mg) was highest with spring-summer drip-irrigation and lowest in summer-fall for both irrigation methods, tracking solar radiation and temperature. This is real, useful operational guidance for anyone running closed-loop substrate zucchini (favor drip over subirrigation in hot/high-light conditions specifically), but does not change any displayed NPK/EC/pH cell, since the underlying recipe is unchanged from what 2009 already supplied.

Rouphael & Colla (2009), HortScience 44(2):306–311 — The Influence of Drip Irrigation or Subirrigation on Zucchini Squash Grown in Closed-loop Substrate Culture with High and Low Nutrient Solution Concentrations

(Università della Tuscia, Italy; real closed-loop peat-pumice substrate culture, genuinely soilless per this file's Rule 7 — tested half (EC 1.0) vs. full (EC 2.0 dS/m) strength nutrient solution across an entire 76-day cultivation cycle on zucchini cv. Afrodite. Full-strength solution composition, stated directly by the paper: NO3-N 173.7, P 37.1, K 195.5, Ca 136.2, Mg 55.9, S 25.6 mg/L (ppm), pH 5.8–6.2, EC 2.0 dS/m — and full-strength gave significantly higher growth, yield, and leaf N/P/K than half-strength across the whole cycle. This is a real, single, non-staged recipe used constantly through the crop's life (not split by Veg/Flower/Fruit), so it does NOT resolve the Veg/Flower stages' extrapolation-from-cucumber problem — but its N/P/K/EC are close in order of magnitude to the existing Fruit-stage Haifa figure (241-39-284 ppm, EC 2.2), independently corroborating that the Fruit stage's general feed strength is right. UPDATE THIS SESSION: the companion paper by the same authors, Rouphael & Colla (2005), Scientia Horticulturae 105:177-195, has now been obtained and read in full (user-supplied), resolving the prior paywall note — see the dedicated 2005 citation below for what it adds (drip vs. subirrigation comparison, growing-season effects), since it confirms the identical base nutrient solution rather than supplying a different one.

Schappelle (1940), Journal of Agriculture of the University of Puerto Rico 25(1):63-72 — The Effect of pH and of Certain Minor Elements on the Growth of Pineapples in Water Cultures

Real, classic, species-exact (Ananas comosus) water-culture trial, Puerto Rico Agricultural Experiment Station — a genuine dedicated pH-optimization study testing SIX real pH levels (2.5, 3.0, 4.0, 5.0, 6.0, 7.0) over a full 6-month growth cycle to harvest, with three replicate plants per treatment. Directly states its complete full-nutrient formula in Table 1: N 100 ppm, P 30 ppm, K 120 ppm, Ca 80 ppm (increased as needed when Ca(OH)2 was used for pH correction), Mg 40 ppm, S variable, plus micros Cu 2, Zn 2, Mn 2, B 1, Al 1, Fe 5 ppm. PROMOTES Pineapple's pH to white/verified at 4.0–4.5 (was blue/hh, a non-academic Howhydroponics-tier figure confirmed as an exhausted dead end in prior sessions) — the paper's own results: no appreciable growth at pH 2.5; good top growth but coarse roots at pH 3.0; progressively better growth at pH 3.0→4.0; increasing chlorosis from pH 5.0–7.0 requiring iron-sulfate spray rescue treatments to keep plants alive; author's own stated conclusion "a pH value of 4.0 to 4.5 was found to be favorable for the growth of the pineapple plant in water cultures." ALSO UPDATES Pineapple's NPK to 100-30-120 (was 56-31-195, Ma et al. 2026's research-isolation figure) — this formula is a genuine complete agronomic feeding recipe (not a deliberately-minimal isolation design) that supported real plants through a full 6-month fruiting cycle; kept at orange/derived rather than promoted to white, since it's from 1940 (pre-modern hydroponic methodology, e.g. Ca was adjusted ad hoc for pH correction rather than held constant) and only a single NPK combination was tested (the pH series varied pH, not NPK). Separately, the minor-element series (full nutrient at fixed pH 4.5, one element omitted per treatment) found Mn and Zn tended to CAUSE chlorosis while Al and B tended to PREVENT it — an indirect effect on iron function, not itself a feeding-target number, but real and notable context for anyone troubleshooting pineapple chlorosis. Cu at 2 ppm controlled a root-rot fungus in the copper-omission treatment.

SciELO Brazil / ResearchGate — Electrical Conductivity and Nitrogen:Potassium Ratios from Nutrigation in the Quality of Zucchini Fruits

(Duarte et al.; real soilless substrate-pot zucchini trial, 5 EC levels × 3 N:K ratios factorial design — found highest fruit fresh mass at EC 3.0 dS/m for N:K ratios of 1:1 or 1:2, or at EC 1.0 dS/m specifically for a 2:1 N:K ratio; corroborates the Fruit stage's EC being in the right general range but doesn't give absolute N/P/K ppm, only ratios — not used to change displayed values, cited as supporting context for the existing Fruit EC)

Semina: Ciências Agrárias (Dantas et al., 2022) — Hydrogen Peroxide and Saline Nutrient Solution in Hydroponic Zucchini Culture

(UFCG, Brazil; control nutrient solution EC 2.1 dS/m, same generic-Hoagland-family baseline as the related Okra and Chives salt-stress studies above — does not give zucchini-specific feeding data, so Squash, Summer's Veg/Flower EC remains derived from Cucumber rather than upgraded)

Son, Joo, Lee, Lim, Park, Choi, Kim & Sim (2021), Industrial Crops and Products 163 — The Changes in Growth Parameters, Qualities, and Chemical Constituents of Lemon Balm (Melissa officinalis L.) Cultivated in Three Different Hydroponic Systems

RESOLVED THIS SESSION — full text obtained directly (user-supplied), settling the paywall block flagged across two prior sessions. Real, genus-exact (Melissa officinalis 'Erfurt upright'), peer-reviewed greenhouse trial comparing three hydroponic systems — artificial soil bed (SCS), perlite bed (PCS), and aeroponic (ACS) — for industrial-scale lemon balm production at Korea Institute of Science and Technology, Gangneung. Section 2.2 states the full base nutrient solution directly: N 354, P 186, K 420, Ca 230, Mg 13, S 83 ppm macronutrients, with EC set DIFFERENTLY per system rather than as a single target — EC 0.5 (artificial soil), EC 1.0 (perlite), EC 1.2 (aeroponic) — renewed every two weeks. **Basis for upgrading Lemon Balm's NPK from the generic, already-flagged-unsupported Cornell herb-category placeholder (150-31-210 ppm) to this real, genus-exact, directly-stated figure (354-186-420 ppm).** EC is shown as the 0.5–1.2 range to honestly reflect that the paper uses three different EC values by cultivation system rather than one target; pH was not stated anywhere in the methods (irrigation water and nutrient solution pH are not given numerically) — Lemon Balm's pH remains yellow/QP Seedlings-sourced. All three systems gave similar aerial-tissue yields; the soilless systems (perlite, aeroponic) increased nitrate content but decreased chlorine content and lowered total phenolic acid/rosmarinic acid/radical scavenging capacity relative to the soil-bed system at 6–10 weeks post-transplant, while caffeic acid and methyl rosmarinate rose 6–8× in the soilless systems — a real cultivation-system flavor/quality tradeoff, noted as context, not reflected in the displayed feeding figures.

Sousa, Dantas, Lima, Soares, Gheyi, Silva, Lopes & Fernandes (2023), Revista Caatinga 36(4):916-928 — Hydroponic Cultivation of Okra Using Saline Nutrition Solutions Under Application of Salicylic Acid

(Universidade Federal de Campina Grande, Brazil; real genus-exact NFT trial, cv. 'Canindé', testing four ECns levels — 2.1, 3.6, 5.1, 6.6 dS/m — as an imposed salinity-stress gradient against four salicylic acid foliar concentrations. The baseline (lowest, unstressed) solution is standard Hoagland and Arnon (1950) at full strength, given in full salt-by-salt form: N 210, P 31, K 234, Ca 200, Mg 48, S 64 ppm, with NaCl/CaCl2/MgCl2 added at a fixed 7:2:1 ratio to create the higher ECns treatments — pH held 5.5–6.5 throughout. Growth, gas exchange, chlorophyll, and relative water content all declined progressively above the 2.1 dS/m baseline, confirming salinity stress onset at the same threshold already cited elsewhere in this file for Okra via a different UFCG/UFC paper. Salicylic acid (3.6 mM) measurably reduced chlorophyll-fluorescence stress markers at the highest ECns but did not rescue yield or water-use efficiency. This is the same generic-Hoagland-baseline pattern already established for Okra — confirms, does not change, Okra's existing EC range (2.0–2.4) and exhausted/yellow NPK status, since no dedicated okra-specific feeding recipe is tested or reported here either.

Tsuneyoshi, Yoshida & Sasaoka (2006), Journal of Nutrition 136(3 Suppl):870S-872S — Hydroponic Cultivation Offers a Practical Means of Producing Selenium-Enriched Garlic

(Wakunaga Pharmaceutical, Japan; real small-bulblet and full-bulb hydroponic garlic cultivation, cv. 'Hokkaido-zairai' — Table 1 states the complete BASE nutrient solution composition (i.e. before any selenium addition) in both a high-sulfate and a sulfate-deficient variant: N 12.7, P 2.2, K 7.1 (+SO4) / 6.2 (−SO4), Mg 1.6/1.5, Ca 1.3/1.5, S 5.5/0 mmol/L — converts to roughly 178N-68P-243K ppm (+SO4 variant) or 178N-68P-242K ppm with Ca 60/Mg 36 ppm (−SO4 variant). This is a genuine, complete, garlic-specific hydroponic macronutrient recipe with full salt-by-salt composition (KNO3, NH4NO3, (NH4)2SO4 or CaCl2·2H2O, KH2PO4, K2SO4, Ca(NO3)2·4H2O or MgCl2·6H2O, MgSO4·7H2O, Na2SO4) — the paper's actual purpose is selenium enrichment via potassium selenate/selenite addition after 14 days, not macronutrient optimization, so the N-P-K figure is incidental to the study's design rather than its tested variable. CONSIDERED AND DECLINED as a fix for Garlic's Bulb/Mature NPK gap (user decision): this is a single flat composition held constant through the entire pre-treatment period, with no Veg/Bulb/Mature staging of any kind — forcing one flat number into this calculator's three growth-stage cells would assert a stage-specificity the source doesn't contain, and would also paper over the staging behavior the existing (incomplete) Chinese K-only trials already hint at — higher K at the bulb/scape stage than at seedling stage. Kept as a citation-only reference. UPDATE: Garlic's Bulb and Mature NPK cells were later upgraded from npkNoSource (pink, no source at all) to npkDerived (orange, has a source with caveats) via a different source — see the Agrinula/Ali et al. 2021 citation's Table 3 figure, applied in a later session. The Veg stage remains its own separate blended figure (see Veg stage note); this Tsuneyoshi figure was not adopted for any stage.

Valenzuela, Fukuda & Arakaki (1994), CTAHR Research Extension Series 146 — Sweetpotato Production Guides for Hawai'i

Real University of Hawaii Extension publication, genus-exact (Ipomoea batatas). Gives two real data points: a field N application rate of 40-50 lbs/acre typical (up to 100 lbs/acre on low-fertility soil), and leaf-tissue sufficiency ranges (N 3.2-4.2%, P 0.2-0.6%, K 2.9-4.3%, Ca 0.75-0.95%, Mg 0.40-0.80%, S 0.22-0.30%, Fe 100-250 ppm, Mn 40-100 ppm) plus petiole sap-test targets (3,500 ppm NO3, 2,000 ppm PO4, 5% K). NOT used to change Sweet Potato's existing unverified ratio figure (5-10-10): the N rate is a soil/field application rate (lbs/acre), not a hydroponic solution concentration, and the tissue/sap-test figures are diagnostic sufficiency standards (what's healthy IN the plant or its sap) rather than a feeding-solution recipe — the same category distinction already applied elsewhere in this file to tissue-analysis sources. Kept as the first real, genus-exact, named source found for sweet potato in this calculator's research history, in case a future session finds a genuine hydroponic sweet potato trial that needs corroboration, or in case Fred wants this used as a last-resort estimate despite its limitations.

Yuan, Zhang & Liu (2026), Horticultural Science and Technology 44(2):211-223 — Biofortification for Radish and Pea Microgreens in Plant Factory: Effects of Different Selenium Concentrations in Nutrient Solution

(Chinese Academy of Agricultural Sciences, Beijing; real, peer-reviewed, species-exact plant-factory-with-artificial-lighting (PFAL) trial on BOTH Radish (Raphanus sativus, red-skin) AND Pea (Pisum sativum) microgreens specifically — matches this calculator's Microgreen - Radish and Microgreen - Pea Shoots rows exactly. The paper's tested variable is sodium selenite biofortification (0-55 µM), not macronutrient concentration — the base feed is described only as "half strength Hoagland nutrient solution," with no elemental N-P-K breakdown given anywhere, so not usable for NPK. However, EC and pH were real, controlled, held-constant targets across all Se treatments and both species: pH adjusted to 5.9, EC 1.0 mS/cm, under 16/8h red:blue (4:1) LED light, harvested at 12 days. This is a real, dedicated, directly-stated EC/pH pair for BOTH species at once, adding a further real data point to Radish's EC/pH conflict — UPDATE (2026-07-10, per Fred's explicit choice): Radish's displayed EC/pH is now sourced to Balik et al. 2024 (1.2-1.6/5.5, promoted to white/verified; see the Balik and Paglialunga citations above), so this paper's 1.0/5.9 now sits as a still-open THIRD real alternative alongside Paglialunga 2023's 0.4-0.8/6.0, rather than a fourth against the prior Di Gioia-lineage figure — and sits close to, but not identical with, Pea Shoots' existing Balik-sourced 1.2-1.6/5.5 (this paper's 1.0/5.9 is slightly lower EC and higher pH). Real finding of note (not applicable to this calculator's single-figure display): total/organic Se accumulation peaked at 35 µM selenite for radish and plateaued at 25-55 µM for pea, while 45-55 µM significantly reduced fresh weight and plant height in both — a biofortification-dosing result, not a base-feed recommendation. Not applied to either row's displayed EC/pH — logged alongside the existing conflicts for Fred's eventual choice.

Dantas, Lima, Gheyi, Silva, Silva, Soares, Lopes & Roque (2022), Semina: Ciências Agrárias 43(3):1167-1186 — Hydrogen Peroxide and Saline Nutrient Solution in Hydroponic Zucchini Culture

Real, species-exact (Cucurbita pepo cv. Caserta) NFT hydroponic trial (UFCG, Brazil) testing H2O2 foliar spray against saline nutrient solution stress. Table 1 gives the real, complete, directly-stated control (non-saline) nutrient solution composition — a standard Hoagland & Arnon (1950) recipe: 210N-31P-234K-200Ca-48Mg-64S ppm, EC 2.1 dS/m. This is a THIRD real, dedicated zucchini data point alongside the standing Squash, Summer Fruit-stage conflict (Pacheco et al. 2023's 209-31-425 vs. Kalaivanan et al. 2020's T3 168-16-189) — notably, this paper's N and P (210-31) sit almost exactly between the other two already-conflicting figures, while its K (234) is far below both. However, this is the paper's baseline/control solution (a standard Hoagland recipe used as the constant, non-experimental backdrop to the actual salinity/H2O2 variables), not itself an outcome-optimized feeding target the way the other two are — so it is logged as further corroborating evidence for the standing 3-way K disagreement rather than displacing either existing figure. Squash, Summer's displayed Fruit-stage NPK (209-31-425) is unchanged.

Rouphael, Colla, Battistelli, Moscatello, Proietti & Rea (2004), Journal of Horticultural Science & Biotechnology 79(3):423-430 — Yield, Water Requirement, Nutrient Uptake and Fruit Quality of Zucchini Squash Grown in Soil and Closed Soilless Culture

Real, peer-reviewed, species-exact (Cucurbita pepo cv. Afrodite) closed-soilless (cocofibre/perlite/pumice, drip-fed, recirculating) greenhouse trial (Italy) directly states its whole-cycle feed recipe (Table, "mg/l"): N-NO3 160, S 26, P 13, Cl 57, K 150, Ca 122, Mg 59, Na 50 ppm, EC 1.8–2.0 dS/m, pH 5.8–6.3. This is a FOURTH real, dedicated zucchini data point for the standing Squash, Summer conflict (alongside Pacheco 209-31-425, Kalaivanan T3 168-16-189, and Dantas et al.'s 210-31-234 control) — notably the lowest P (13 ppm) of any of the four, while its EC (1.8–2.0) sits closest to this row's existing Veg-stage range. Soilless culture significantly outyielded soil (24% higher marketable yield) using this recipe, a real outcome-validated result, but the paper doesn't stage the recipe by growth phase (applied as one constant whole-cycle feed) — logged as further corroborating evidence for the standing multi-way conflict; Squash, Summer's displayed figures unchanged.

Dantas, Lima, Gheyi, Pinheiro, Silva & Soares (2022), Revista Caatinga 35(2):436-449 — Gas Exchange and Hydroponic Production of Zucchini Under Salt Stress and H2O2 Application

Real, species-exact, dedicated NFT zucchini trial (UFCG, Brazil; a companion paper to the already-cited Dantas et al. Semina 2022 H2O2/saline study, same base Hoagland recipe 210-31-234 ppm at EC 2.1 as its control). Real, outcome-validated finding: nutrient-solution EC above 2.1 dS/m caused significant, progressive reductions in stomatal conductance, transpiration, CO2 assimilation, and total fruit number (26.8%/30.1% lower at EC 6.6 vs. 2.1), with total production per plant peaking at EC 2.1 combined with 19 μM H2O2 foliar spray. This corroborates EC≈2.1 dS/m as a real, dedicated, outcome-tested ceiling for zucchini rather than a target to exceed — consistent with, not conflicting with, this row's existing Veg-stage EC (1.2–1.6, below this ceiling) but sitting below the Flower/Fruit-stage EC values (2.0–2.4/3.0) already displayed, which come from different dedicated fruit-yield-optimization trials (Liopa-Tsakalidi, Pacheco). Not applied — logged as real corroborating evidence that supports keeping Fruit-stage EC from climbing further, not as a reason to change any displayed figure.

D'Imperio, Parente & Serio (2024), Future Foods 10:100519 — Exploring Mineral Profiles and Their Bioaccessibility of Chicory, Swiss Chard, and Black Cabbage Microgreens

Real, peer-reviewed, species-exact microgreens trial (CNR Bari, Italy) covering Chicory and Swiss Chard microgreens specifically (plus black cabbage, not a row in this calculator). States a real, complete, directly-stated feed recipe used for all three species after germination: half-strength Hoagland (½ NS) — 112N, 120K, 80Ca, 31P, 16S, 12Mg ppm, N-NO3:N-NH4 ratio 84:16, pH 5.5–6.0. The paper's main findings are mineral CONTENT and in-vitro digestive BIOACCESSIBILITY of the harvested tissue (e.g. Swiss chard microgreens had markedly higher Ca/K/Mg/Fe/Zn than chicory or black cabbage) — tissue composition, not a feeding-target result, so per this file's standing Rule 8 the bioaccessibility findings themselves aren't usable for NPK/EC/pH. The feed recipe itself (112-31-120 ppm, pH 5.5–6.0) is real and shared identically across both species — a candidate Microgreen-stage figure for Chicory and Swiss Chard if this calculator adds microgreen-stage rows for either; not applied since neither currently has a microgreen-stage entry.

Luna-Maldonado, Rodríguez-Fuentes, Rodríguez-Ortiz, Vidales-Contreras, Márquez-Reyes & Flores-Breceda (2016), Journal of Experimental Biology and Agricultural Sciences 4(6):637-643 — Cultivation of Rosmarinus officinalis in Hydroponic System

Real, species-exact, genuinely hydroponic (volcanic-rock substrate) rosemary population-density trial (Nuevo León, Mexico) — the source cited elsewhere in this file for the Rodríguez-Fuentes rosemary nutrient table. Table 1 gives the real, complete, directly-stated feed composition: N 200, P 60 (as KH2PO4), K 250 (as KNO3), Ca 200, Mg 50, S 100 ppm, plus micronutrients — this is the SAME recipe already referenced elsewhere in this file as the "Rodríguez-Fuentes" nutrient table; full text confirms it directly rather than via secondary citation. pH/EC not stated in this paper (fertigation via timer-controlled drip, no EC/pH reading given). Not applied beyond confirming the existing citation; Rosemary's NPK remains sourced to the Nghiem et al. 2023 F4 figure (150-100-200), which this paper's 200-60-250 corroborates in ratio-shape (N and K roughly balanced, P much lower) without being identical.

De Rijck, Schrevens & De Proft (1994), Acta Horticulturae 361:226-236 — Cultivation of Chicory Plants in Hydroponics

Real, peer-reviewed, species-exact (Cichorium intybus) hydroponic (rockwool, drip-fertigated) chicory trial — an earlier conference-proceedings companion to the De Rijck & Schrevens (1998) Scientia Horticulturae journal paper by the same research group (K.U. Leuven, see dedicated entry above), reporting essentially the SAME vegetative-phase base recipe (Table 1: K+ 11.00, Ca++ 5.50, Mg++ 1.50, NO3- 12.50, H2PO4- 3.75, SO4-- 3.125, Cl- 2.5 mmol/L, used for the first 45 days) that converts to the same ~175N-116P-430K ppm figure already logged as the 5th Chicory NPK conflict data point — not a new/independent source, so not counted as a 6th. This paper's own experimental variable was 10 different anion-ratio nutrient solutions (all at a fixed lower total ionic strength, 16 meq/L) applied AFTER the initial 45-day period, showing real, dedicated findings that higher nitrate in the plant-growth-phase solution increased leaf/root vegetative growth (more leaves, longer leaves, heavier leaf and root weight) but produced smaller, lower-quality forced chicons (chicory heads) — mirroring the same vegetative-growth-vs-forcing-quality tradeoff already noted from the 1998 paper. Not applied to any displayed figure; kept as confirming/duplicate citation.

De Rijck & Schrevens (1998), Scientia Horticulturae 76:149-159 — Multifactorial Optimisation of the Nutrient Solution for Hydroponically Grown Chicory Plants

CORRECTION (2026-07-12, per Fred): this paper had only ever been referenced BY NAME inside the 1994 companion-paper note above ("already-cited De Rijck & Schrevens (1998)...") — it never had its own dedicated citation entry in this file, despite the phrasing implying it did. Fred supplied the full PDF; entry now added properly. Real, peer-reviewed, species-exact (Cichorium intybus, witloof/Belgian-endive forcing type, K.U. Leuven) study with TWO growing phases: (1) light-grown vegetative phase (first 45 days, fixed recipe, Table 1: K+ 11.00, Ca++ 5.50, Mg++ 1.50, NO3- 12.50, H2PO4- 3.75, SO4-- 3.125, Cl- 2.5 mmol/L → ~175N-116P-430K-220Ca-37Mg-100S ppm) and (2) dark-forcing phase (roots forced post-cold-storage to produce the harvestable chicon, no photosynthesis, 10 varied anion-ratio mixture-design solutions at a fixed lower 16 meq/L total strength). Phase 2 is NOT applicable to this calculator's Chicory/Radicchio rows, both modeled as ordinary light-grown crops. Phase 1's recipe is logged as the 5th real, disagreeing data point in the standing Chicory NPK conflict (alongside MISR/Alaswad 162-25-182 [displayed], Oliveira 2023 190-81-215, Andriolo 2008 224-47-390, Curci 2026 ~91-13-67) — not applied to displayed figures. Real, dedicated finding: higher nitrate in the vegetative-phase solution significantly increased leaf/root growth (germination rate, root vigor/TTC, root length/weight/surface-area density, root/shoot ratio all improved with magnetization/oxidation treatments layered on top) but produced smaller, lower-quality forced chicons — an agronomic tradeoff finding, not itself a ppm target. Note: this paper investigates ANION ratio (NO3/H2PO4/SO4/Cl) as a mixture-constrained system specifically for the forcing phase, not a general NPK optimization — distinct in method from the 1994 companion paper it's often discussed alongside.

Oliver, Coyle, Bright, Shultz, Hager & Tidwell (2017), Journal of the World Aquaculture Society — Comparison of Four Artificial Light Technologies for Indoor Aquaponic Production of Swiss Chard and Kale

Real, species-exact aquaponic (tilapia-fed, not mineral-fertigated) Swiss Chard trial (Kentucky State University) comparing LED/metal-halide/induction/fluorescent grow lights — LED gave significantly higher biomass, yield/m², and energy efficiency than the other three lights for both Swiss chard and kale. Real recorded system water quality during the Swiss chard trial: pH 7.16±0.6, conductivity 306.6±8.1 (units as reported, unusually low for a dedicated feed EC — this is fish-tank-derived aquaponic water, not a formulated mineral nutrient solution, so not directly comparable to this calculator's hydroponic EC figures). Leaf TISSUE N/P/K/Ca/Mg/S percentages are also reported (Table 2) but are tissue-sufficiency data, not a feed recipe — per this file's standing Rule 8, not usable for NPK. Not applied to Swiss Chard's existing NPK/EC/pH; the lighting-technology comparison itself is outside this calculator's scope (nutrient solutions only).

Suvo, Ahamed, Haque, Chakrobarti & Biswas (2016), International Journal of Agricultural Research, Innovation and Technology 6(2):1-4 — Identification of Suitable Media Based on Hydroponic Culture for Production of Zucchini Squash

Real, species-exact zucchini substrate-comparison trial (Patuakhali, Bangladesh) — jute fiber, coconut husk, and cotton substrates all fed the same Hoagland & Arnon (1950) base solution, EC maintained 1.8–2.4 dS/m (citing Pardossi et al. 2002) — jute fiber substrate significantly outperformed the others on yield, leaf number, and fruit quality (ascorbic acid, protein); cotton substrate had no fruit set at all. Real corroboration of an EC range overlapping this row's existing Flower-stage EC (2.0–2.4) and above its Veg-stage EC (1.2–1.6); the underlying Hoagland composition itself isn't independently restated in what could be fetched, so not usable as a fresh NPK source. Not applied — logged as further EC-range corroboration; a real note that substrate choice (not just nutrient solution) meaningfully affects zucchini yield in soilless systems.

Fayezizadeh, Alemzadeh Ansari, Mahmoodi Sourestani & Hasanuzzaman (2023), Agriculture 13(9):1691 — Basil Microgreens Under Five Hoagland Concentrations (25–125%)

Real, but uses generic %-of-Hoagland dilutions rather than a stated elemental recipe, and is a microgreen-stage study (already treated as a distinct growth stage elsewhere in this file). Main finding: 50% strength maximized yield, 125% maximized antioxidants — a real yield-vs-quality tradeoff, but not convertible to a feed-target ppm figure. Not applied.

Berryplants Ltd / Plant Sciences Inc. / Delphy — Substrate Nutrition Guidelines: PSI Raspberry Varieties (Nobility, Ovation, Paragon, Majestic)

Real, cultivar-exact, industry-published commercial coir-substrate fertigation guide for four proprietary PSI raspberry varieties, covering both Primocane/Nursery and Floricane (long-cane) cropping systems with complete, directly-stated mmol/L recipes (Figures 1 & 2). Converted to ppm — Primocane 'Nobility': Veg N 143-P40-K141-Ca136-Mg39-S42, EC feed 1.4/EC sum 3.0-3.6mS, pH 5.3; Fruiting N168-P37-K227-Ca120-Mg34-S32, EC feed1.5/sum3.6-4.2mS, pH5.3. Long Cane 'Ovation/Majestic/Paragon': Starter N200-P40-K133-Ca148-Mg44-S39, EC feed1.7/sum3.0-3.6mS, pH5; Fruiting N172-P34-K219-Ca120-Mg39-S32, EC feed1.6/sum3.6-4.2mS, pH5. Also gives real target K:Ca ratios (0.9-1.1 starter, 1.8-2.0 fruiting) and drip pH 5.1-5.3 "for good Iron/Manganese availability." This is real, complete, and notably detailed — but a commercial nutrition consultancy's product-specific guide, not an outcome-tested academic trial, and it conflicts with Raspberry's existing verified, outcome-tested Bazangeya et al. 2025 figures (particularly on pH: 5.0-5.3 here vs. 5.5-6.5 there, and much higher EC-sum figures which include drain/runoff EC, not directly comparable to a feed-only EC target). Logged as a real, high-quality corroborating/conflicting citation; not applied — Raspberry's displayed NPK/EC/pH unchanged.

Chatzigianni, Ntatsi, Theodorou, Stamatakis, Livieratos, Rouphael & Savvas (2019), Frontiers in Plant Science 10:1040 — Functional Quality, Mineral Composition and Biomass Production in Hydroponic Spiny Chicory (Cichorium spinosum L.) Are Modulated Interactively by Ecotype, Salinity and Nitrogen Supply

Real, peer-reviewed, species-exact (Cichorium spinosum, two Cretan ecotypes) perlite-bag hydroponic trial (Agricultural University of Athens / Mediterranean Agronomic Institute of Chania) — same species as the Voutsinos-Frantzis citation above, a DIFFERENT species than this file's existing Chicory row (Cichorium intybus). Table 1 gives a real, complete, directly-stated non-saline control recipe (mmol/L): K+ 7.50, Ca2+ 4.40, Mg2+ 1.50, NO3- 3.00 (low-N) or 15.00 (high-N), H2PO4- 1.20, SO4-- 4.81 (low-N) or 1.84 (high-N), pH 5.60, EC 2.10 dS/m — converts to roughly 42N-37P-293K ppm (low-N treatment) or 210N-37P-293K ppm (high-N treatment), Ca 176, Mg 36. Both N levels gave statistically equal shoot biomass (a real, notable N-use-efficiency finding — the paper's own conclusion is that stamnagathi tolerates a 4-fold N reduction without yield penalty). Real, complete, high-quality data — but for Cichorium spinosum specifically, NOT this file's Cichorium intybus Chicory row, so not applied there. Flagged as a genuine candidate if Fred ever wants to add "Spiny Chicory" (stamnagathi) as its own distinct row — real EC/pH/NPK data already exists and would need no further sourcing.

Conversa, Bonasia, Lazzizera, La Rotonda & Elia (2021), Frontiers in Plant Science 12:645671 — Reduction of Nitrate Content in Baby-Leaf Lettuce and Cichorium endivia Through the Soilless Cultivation System, Electrical Conductivity and Management of Nutrient Solution

Real, peer-reviewed, open-access (University of Foggia, Italy), species-exact for Endive (Cichorium endivia var. crispum, cv. 'Atleta', floating/ebb-and-flow systems) grown alongside romaine lettuce. Directly states the complete basic nutrient solution composition: N 140, P 50, K 200, Ca 100, Mg 38.4, S 136 mg/L, NO3:NH4 ratio 4:1, micronutrients at Hoagland-solution concentrations, pH maintained 5.5–6.5. PROMOTES Endive's NPK to white/verified at 140-50-200 ppm, replacing the prior orange/derived 224-31-390 figure — a straightforward gap-fill (Corrective Lesson #3), since Endive's NPK carried no real dedicated source before this. pH (5.5–6.5) matches the already-displayed figure exactly — real corroboration, no conflict. EC: this paper's own base/unstressed NS measures 2.41 dS/m (before the study's own NaCl salinity manipulation to 2.5/3.5 dS/m) — a real figure that DISAGREES with Endive's already-verified EC (1.6, sourced from a separate real Brazilian trial recommending 1.6 for SH/DFT systems). Per Corrective Lesson #12, this is a genuine 2-way EC conflict, not applied — Endive's displayed EC (1.6) is unchanged, logged for Fred's eventual judgment.

Currey (Greenhouse Grower) — Managing Electrical Conductivity (EC) for Hydroponic Basil Production

Real, species-exact NFT trial on sweet, holy, and lemon basil across EC 0.5–4 mS/cm and two DLI levels, using a generic commercial fertilizer (16N-1.8P-14.3K, Jack's Hydro FeED). Key finding: EC had NO significant effect on basil growth across that entire range — tissue nutrient levels stayed within or above sufficiency even at the lowest EC tested. Real and useful confirmation that basil is EC-flexible, but gives no single target value to apply; Basil's existing EC/NPK are unaffected.

FAO (2014) — Use of Algae and Aquatic Macrophytes as Feed in Small-Scale Aquaculture: A Review, Ch. 3 "Floating Aquatic Macrophytes – Duckweeds"

Real, extensively-sourced review (aquaculture/wastewater-treatment context, not hydroponic vegetable production, but directly on-topic for duckweed nutrient concentration) citing dozens of primary studies. Table 3.4 gives real, literature-summarized optimum ranges: N (as NH3-N) optimum 7–12 mg/L (max tolerated 375 mg/L before toxicity), P (PO4-P) optimum 4–8 mg/L (max 154 mg/L), pH optimum 6.5–8.0. Table 3.3 gives K 0.5–100 mg/L (95% of samples 1.0–30), Ca 0.1–365 (95%: 1.0–80), Mg 0.1–230 (95%: 0.5–50), S 0.03–350 (95%: 1.0–200). Real field/lagoon data cited throughout (Culley et al. 1981 and others) consistently describes "high-nutrient" duckweed lagoons achieving strong yields in the 15–65 mg/L TKN range — well below Hoagland strength (~210 ppm N), let alone the 4× Hoagland level (~840 ppm N) implied by the Jin et al. side of the open conflict. RELEVANT CONTEXT for the NPK question: this source leans toward the LOWER end (closer to the prior incumbent 24-3-25 placeholder and to Petersen et al. 2022's 14-3-36, now Duckweed's displayed white/verified NPK per Fred's 2026-07-11 choice) rather than validating Jin et al.'s much higher figure, though it's an aquaculture-pond context rather than a controlled hydroponic NFT/DWC trial, so it's not a perfect like-for-like comparison either.

Al Jenaid, El Mahi, Bathaqili, Alalawi, Nair, Nishanth, Subramanian, Manoharan & Jaleel (2026), PLOS One 21(1):e0340364 — Nutrient Film Technique Systems for Coriander Production: A Comparison of Aquaponics and Hydroponics in UAE

(United Arab Emirates University; real species-exact (Coriandrum sativum) NFT trial in a greenhouse, comparing a hydroponic arm (commercial "Max Grow Company" two-part nutrient solution, 5 mL each of Solution A and B per liter) against an aquaponic arm (Nile Tilapia waste, no mineral supplementation) over 8 weeks. The hydroponic product's disclosed composition is itself incomplete and appears to contain a transcription gap in the source paper: Solution A is reported as "26.2% K, 39% Ca, 17.4% Fe, 34%" (an unlabeled fourth percentage with no element given) and Solution B as "3.62% P2O5, 5.61% Mg, 7.4% S, 0.06% Mn" — NITROGEN IS NEVER STATED for either part, anywhere in the paper. Per this calculator's standing Rule 5, a triplet missing N entirely cannot be completed by inference no matter how complete the other elements are, so this is not usable as Cilantro's NPK source. The paper does report real measured EC/pH over time for the hydroponic reservoir (EC declining 1.36→0.671 mS/cm, pH declining 7.15→6.58 over 8 weeks) — but this is a depletion curve from nutrient uptake/dilution in a closed reservoir, not a recommended or maintained target range, so it is not directly comparable to Cilantro's existing EC 1.75/pH 6.0 derived figures (themselves sourced from Jack's Nutrients' leafy-greens schedule, a different kind of figure — a fixed target rather than a measured trajectory). Kept as a real, genus-exact, hydroponic-NFT-qualifying citation — useful corroborating context (e.g. confirming coriander tolerates a wide EC range without obvious stress) but not a number source. Does not change Cilantro's existing derived NPK/EC/pH.)

Boonen, Herckens & Bylemans (2019), Acta Horticulturae 1265:165-169 — A Well-Balanced Nutrient Solution for Raspberries

(pcfruit npo/KU Leuven, Belgium; real substrate-culture (cocopeat/cocofiber/turf/perlite, genuinely inert — no soil) greenhouse fertigation trial on primocane cv. 'Kwanza', same fruiting type as the verified Bazangeya et al. 2025 source already used for Raspberry. Gives real, stage-specific NH4+/NO3-/K+/Ca2+ millimolar concentrations (e.g. growth phase 1.4mM NH4 + 10.5mM NO3 ≈ 166 ppm N; flowering/harvest phase tested at two K levels, 5.8mM and 8.0mM K ≈ 227 and 313 ppm) and a real K:Ca ratio finding (0.92 during growth, rising to 1.14 during fruiting) — but PHOSPHORUS IS NEVER STATED ANYWHERE in this paper, for any treatment or phase; only N, K, and Ca are given. Per this calculator's standing Rule 5 (never fabricate a missing nutrient to complete a partial triplet), this cannot be converted into a usable NPK figure no matter how complete the other two elements are. Kept as a real, genus-and-fruiting-type-exact, substrate-qualifying citation — useful corroborating context (e.g. its real K-rises-before-fruiting-set finding, also already reflected directionally in Bazangeya's K-by-stage progression) but not a number source. Does not change Raspberry's existing verified NPK/EC/pH.

Extrapolated estimate — ratio-only guess, or derived from a related crop/general principle backed by real academic or extension data

Industry-sourced, not academically verified

Howhydroponics — EC, pH, and PPM Reading Chart for Hydroponics

QP Seedlings — Optimal NPK Ratios, Electrical Conductivity (EC) and pH Levels for Growing Vegetables (initial design inspiration)

Please forward any relevant academic studies to Fred Thompson (see buttons at the bottom of the page.)

Only hydroponic/soilless technical material from sources listed below may be used to upgrade/improve purple-tier ("Industry-sourced, not academically verified") cells.

Aquaponics WA / Hydroponic Xpress

Active. Canning Vale, Western Australia. Retail hydroponics/aquaponics store (not a manufacturer) trading under both names — same company already cited in this file's "Primary Sources" list under "Hydroponic Xpress" for its EC/pH wall-chart guide. Use only their own published technical material, not third-party product listings carried in their shop.

Botanicare

Active. Founded 1994, Chico, CA. Owned by Hawthorne Gardening Co. (Scotts Miracle-Gro) since 2016.

CANNA

Active. Founded 1979, Dongen, Netherlands. Product range spans hydroponics/cocoponics/soil — use ONLY hydroponic-specific lines and data. US-facing site linked above; also at canna.com and canna-uk.com.

Dyna-Gro Nutrition Solutions

ARCHIVED/HISTORICAL ONLY. Founded 1983, acquired by Green Garden Products June 2020, original company no longer operating independently; domain now redirects to Ferry-Morse (home-garden retailer, not commercial). Use only pre-June-2020 material. Archival feed chart mirror linked above (originally hosted at dyna-gro.com/wp-content/uploads/2016/11/DG_feedchart.pdf).

Haifa Group

Active. Founded 1966, Israel. Has a dedicated hydroponics technical product line — use ONLY that line, not their soil/field-crop guides.

Hydro-Gardens (Chem-Gro)

ARCHIVED/HISTORICAL ONLY. Founded 1968 (blending Chem-Gro since 1965), Colorado Springs, CO, Morton family. Company closed 2023. Use only material present as of the March 2023 archive snapshot linked above. Also see the F.A.Q Page (archived Feb 2023).

ICL Specialty Fertilizers (Peters Professional)

Active. Successor to the original "Peters Professional" brand name (distinct corporate lineage from JR Peters/Jack's).

Jack's Nutrients (JR Peters, Inc.)

Active. Founded 1947, Allentown, PA, family-owned, in-house analytical lab. Also at jacksnutrients.com.

Klaros Tarım

Active. Turkey. Soilless-agriculture greenhouse installation and consultancy company, 7 years' experience, specializing in strawberry, blueberry, raspberry, and blackberry cultivation, with projects in both Turkey and the US. Site is a JS-rendered SPA, not directly fetchable with this session's tools — Fred supplied the actual page text directly from four pages (raspberry/ahududu, blackberry/bogurtlen, blueberry/yaban-mersini, and a "nutrition recipes"/beslenme-programlari page compiling several named third-party formulas). Treated as genuine, reviewed technical material as of 2026-07-04 — see the Raspberry/Blackberry/Strawberry/Blueberry citation entries for what was extracted and applied.

Masterblend International

Active. Namesake brand of this calculator (4-18-38 Tomato Formula).

Plant Marvel Laboratories

Active. Founded 1957, Chicago Heights, IL. Commercial greenhouse/nursery focus.

Rivulis

Active. Global drip/micro-irrigation and fertigation equipment manufacturer (Israel-founded, now multinational). Added per Fred's explicit instruction (2026-07-04). Their own published stage-specific Blueberry fertigation program was supplied by Fred via Klaros Tarım's site content — see the Blueberry citation entries.

Yara International

Active. Founded 1905 (Norsk Hydro fertilizer division, spun off 2004). Large diversified company — use only their horticulture/greenhouse division technical material.

Extrapolated estimate — ratio-only guess, or derived from a related crop/general principle backed by real academic or extension data

Industry-sourced, not academically verified

Howhydroponics — EC, pH, and PPM Reading Chart for Hydroponics

QP Seedlings — Optimal NPK Ratios, Electrical Conductivity (EC) and pH Levels for Growing Vegetables (initial design inspiration)

Please forward any relevant academic studies to Fred Thompson (see buttons at the bottom of the page.)

Automation / IoT / Electronics (off-topic for crop nutrition — logged for reference only, found during the systematic blog crawl):

DIY sensor builds, HydroBuddy software features/releases, data-logging platforms, and commercial monitoring hardware — real content, but never crop-specific NPK/EC/pH data, so none of it changes any cell in this calculator. Kept here rather than discarded so this list isn't silently re-crawled in a future pass.

A new conductivity model in HydroBuddy About the default fertilizer database in HydroBuddy Building a DIY control infrastructure for a hydroponic crop: Part one Calibrating a capacitive moisture/water content sensor for hydroponics Commercial sensor and data logging solutions for hydroponics Creating a pH/EC wireless sensing station for MyCodo using an Arduino MKR Wifi 1010 Dutta, Gupta, Juneja, AlNadhari & Belhaouari (2025), Scientific Reports 15:10164 — Machine Learning Insights for Sustainable Hydroponic Cultivation and Growth Monitoring of Allium cepa Using Smart Hydro Kit Hardware for building a wifi-connected DIY monitoring/control system for a hydroponic crop How to identify resistive moisture sensors and why to never use them in hydroponics HydroBuddy coming to Android, free and open source! HydroBuddy has now been updated to v1.70: New features and modifications Improving on HydroBuddy's theoretical conductivity model, the LMCv2 Making the most out of your hydroponic setup's logged sensor and control data MyCodo: an open-source solution for control, data logging and visualization Practical use of ion selective electrodes in hydroponics Properly positioning temperature and humidity sensors in a hydroponic growing environment Pros and cons of building your own sensor and data logging system in hydroponics Singgeta, Lin & Chang (2016), Proc. 24th Conference on Automation Technology, National Chung Hsing University — Raspberry Pi based pH Control for Nutrient Film Hydroponic System Six things to look for in a Hydroponic sensor data logging system Tensiometers (irrometers): the best way to time irrigations in hydroponics The best cheap sensor setup for relative humidity in hydroponic automation projects The Chirp Sensor: A plug-and-play solution to moisture monitoring in hydroponics The cricket IoT board: A great way to create simple low-power remote sensing stations for hydroponics Timing irrigations with moisture sensors in hydroponics Top 5 Open Source Hardware Tools to Boost Your Hydroponic Yields Using VH400 sensors to build an automated irrigation setup Companion planting / intercropping / mixed crop / polycropping (real, on-topic sources found and evaluated, none applied to any displayed NPK/EC/pH figure — these are agronomic-outcome or engineering-optimization studies, not feeding-recipe sources): Description, Operation and Production of the South Pole Food Growth Chamber

Real engineering/operations paper describing a mixed-crop hydroponic growth chamber at the Amundsen-Scott South Pole Station — an extreme-environment analog facility, not a nutrient-concentration optimization study. Logged for reference; no usable NPK/EC/pH data extracted.

Ding, Ali & Cheng (2020), Plants 9(1):45 — An Allelopathic Role for Garlic Root Exudates in the Regulation of Carbohydrate Metabolism in Cucumber in a Hydroponic Co-Culture System

(Northwest A&F University, China; real hydroponic co-culture trial, Hoagland base solution, pH 6.2 ± 0.1, testing 0/5/10/15/20 garlic plants co-cultured with 2 cucumber plants over 36 days. Real finding: garlic root exudates inhibited cucumber growth, increased oxidative stress markers (MDA, ROS), and altered carbohydrate partitioning — a companion-planting/allelopathy mechanism study, not a feeding-recipe source. Companion study to the same group's garlic/pepper work below. Not applied to Cucumber's NPK/EC/pH.)

Ding, Ali & Cheng — Garlic Exerts Allelopathic Effects on Pepper Physiology in a Hydroponic Co-Culture System

(Same research group and hydroponic co-culture design as the cucumber study above, applied to pepper instead — 0/2/4/8/12 garlic plants co-cultured with 2 pepper plants. Real finding: pepper response was dose-dependent, with low garlic concentrations showing a growth-promotion effect and high concentrations becoming deleterious — the opposite pattern from the cucumber study, where all garlic quantities were phytotoxic. Real allelopathy/companion-planting mechanism data, not a feeding-recipe source. Also mirrored at journals.biologists.com/bio/article/5/5/631/1434/. Not applied to Peppers' NPK/EC/pH.)

D-Andrade, Escalante-Garcia, Olvera-Gonzalez, Orsini, Pennisi, Vega de Luna, Silos-Espino & Najera (2025), Plants 14(13):2060 — Intercropping Lettuce with Alfalfa Under Variable Nitrate Supply: Effects on Growth Performance and Nutrient Dynamics in a Vertical Hydroponic System

(Tecnológico Nacional de México/University of Bologna/Institut de Biologie Physico-Chimique/University of Almería; real vertical-farm NFT trial, lettuce (Lactuca sativa var. longifolia) intercropped with Rhizobium-inoculated alfalfa (Medicago sativa) at 0/33/66/100/133% nitrate levels vs. a full-nitrate lettuce monoculture control. Real findings: the 66%-nitrate intercropped treatment gave the best water-use efficiency (+38% vs. monoculture) and lowest leaf nitrate accumulation, but the full-nitrate monoculture control still produced the highest overall biomass — a resource-efficiency tradeoff study, not a feeding-recipe optimization for either species. States a full macro/micronutrient solution-balance protocol (Table 5/6 in the paper, EC 2.0±0.5 mS/cm, pH 6.0±0.5) but this is a generic balanced base solution modified only by N-source scaling, not a species-specific recommended target. Also mirrored via citedrive.com. Not applied to Lettuce's existing NPK/EC/pH.)

Edney, Richards, Sisko, Yorio, Stutte & Wheeler — Compatibility of Radish, Lettuce and Bunching Onions Grown Hydroponically in a Mixed-Crop System

(NASA Kennedy Space Center CELSS-adjacent research group; real three-species mixed-crop hydroponic compatibility study — radish, lettuce, and bunching onion grown together vs. as monocultures, evaluating whether the three species compete or complement each other in a shared system. Companion research to the "Mixed Crop Versus Monoculture" and "Mixed vs. Monoculture Hydroponic Production of Salad Crops at Three CO2 Concentrations" work by the same group (see below and the nimss.org publication list entry). Agronomic compatibility outcome study, not a feeding-recipe source. Not applied to Radish, Lettuce, or bunching Onion's NPK/EC/pH.)

Edney, Richards, Sisko, Yorio, Stutte & Wheeler — Evaluation of Salad Crop Growth under Environmental Conditions for Space Exploration using Mixed Crop Versus Monoculture Hydroponic Systems

(Same NASA-adjacent research group as above; real HortScience 41(4) conference-abstract-format paper comparing mixed-crop vs. monoculture salad-crop hydroponic production under simulated space-exploration environmental conditions. Also hosted at ResearchGate publication 330786573. Companion work to the group's other mixed-crop/CO2-concentration studies referenced in the nimss.org NCERA_OLD101 publication list (Edney et al. 2006, Proc. Plant Growth Reg. Soc. 32:133-140; Edney et al. 2007, Proc. 33rd PGRSA Annual Meeting:193-200) — the nimss.org page itself is a multistate research committee's aggregated publication list (hundreds of entries spanning 2006-2010), not a single citable paper. Real agronomic-compatibility findings, no feeding-recipe ppm table for any individual crop; not applied to any row.)

Maucieri, Nicoletto, Schmautz, Sambo, Komives, Borin & Junge (2017), Agronomy 7(4):63 — Vegetable Intercropping in a Small-Scale Aquaponic System

(Zurich University of Applied Sciences/University of Padova; real small-scale aquaponic (Pangasius catfish) NFT trial, lettuce intercropped with red chicory, 6-week greenhouse experiment. Real finding: intercropping did not significantly affect water quality (pH, EC, DO) or overall vegetable yield, but did shift quality traits — increased lettuce sugar content, reduced its caffeic acid, and altered red chicory's bitter-compound profile; fish growth parameters trended better (not significantly) with red chicory present, attributed to improved water quality from lower NH4+/NO2- levels. Also hosted at hero.epa.gov/reference/6403781. Real aquaponic/companion-planting outcome study, not a base feeding-recipe source (the system used standard aquaponic fish-waste nutrient cycling, not a formulated mineral solution). Not applied to Lettuce's NPK/EC/pH.)

Roth, T. (2026), University of Waterloo PhD Thesis — Process Intensification of Sustainable Production Systems through Integrated Modeling and Optimization

(Advisor: Ricardez Sandoval, Luis; Dept. of Chemical Engineering. Very recent (April 2026) doctoral thesis; first study develops an optimization framework for monoculture vs. polyculture hydroponic operating strategies, incorporating interspecies nutrient-interaction and dynamic environmental-disturbance modeling, validated against experimental data. Case study: hydroponic polyculture soybean+tomato vs. monoculture. Real, quantified findings: polyculture reduced nitrogen consumption by 40% and increased annual profit by 3.91% per kilogram of fruit compared to monoculture hydroponics, with both approaches showing >60% yield increase over traditional soil farming. This is a systems-engineering optimization-framework result (nitrogen SAVINGS relative to a baseline), not a stated elemental ppm feeding recipe for Soybean or Tomato specifically — the thesis's second study is unrelated (aviation biofuel process design). Likely the source thesis behind ResearchGate publication 397147211, "Enhancing Sustainable Agriculture through Optimized Polyculture Hydroponic Operating Strategies" (not independently fetched — same author/topic, presumed to be a derived journal article from this thesis chapter). Not applied to Tomato's existing verified NPK/EC/pH, since the 40% reduction is relative to an unspecified monoculture baseline rather than a stated absolute target.)

CABI Digital Library record 10.5555/20083058219 (title unconfirmed)

Surfaced in the same companion-planting/intercropping URL batch as the sources above (2026-07-05 session) but genuinely unreachable — bot-blocked on direct fetch, and no usable title/abstract found via search-snippet fallback either that session or on a repeat check (2026-07-12). This is a CAB Abstracts accession number, not a standard resolvable DOI. Title, authors, and content remain unconfirmed; not evaluated for relevance. Revisit only if Fred can supply the title/citation via institutional CABI access.

Verdoliva, S. (2021), Aberystwyth University PhD Thesis — Investigation of New Techniques to Improve Quality and Resource Use Efficiency in Soilless Protected Horticulture

Real doctoral thesis (supervised by Dylan Gwynn-Jones & Paul Robson). Covers three studies: (1) hydroponic tomato quality vs. soil-grown, (2) hydroponic intercropping — found that concentrated hydroponic nutrient solutions allow two crops to be grown concurrently with mild competition that can enhance the companion crop's growth (tomato/basil deep-water-culture system), and (3) tomato and banana waste extracts as a circular-economy fertilizer source, with banana extract showing particular promise as a potassium-based supplement. Real, quantified findings but no elemental N-P-K/EC/pH feeding-recipe table given for any specific crop in this calculator; not applied. Full PDF available via the page's document link.

No relevant information found: Zhao, Zhou, Mu, Wang, Liu & Wang (2021), Agronomy 11(12):2459 — Irrigation with Activated Water Promotes Root Growth and Improves Water Use of Winter Wheat

NOT APPLICABLE. Winter Wheat is not a tracked crop in this calculator (not in the Fruit/Vegetable/Herb/Microgreen row set), so there is no row to apply this to even setting the content aside. The paper itself is also not a nutrient-recipe source regardless: it studies magnetization/oxidation WATER-TREATMENT effects (not fertilizer composition) on winter wheat root vigor, root length/weight/surface-area density, and field grain yield/water-use efficiency, comparing treated vs. untreated groundwater and brackish water. No NPK/EC/pH feeding-solution target is given anywhere in the paper — it's an irrigation-water-activation study, not a nutrient-solution-formulation study. Nothing extractable for this calculator's schema.

Melo & Santos (2011), Horticultura Brasileira 29(4):584-589 — Growth and Production of Nasturtium Flowers in Three Hydroponic Solutions

Nasturtium (Tropaeolum majus) is not currently a row in this calculator. Real NFT hydroponic growth trial (UFSM, Brazil) testing three generic lettuce-formulated nutrient solutions — Hoagland & Arnon (1950), Castellane & Araújo (1995), and Furlani (1997), full compositions given in the paper's own Table 1 — on nasturtium canopy height, leaf area, LAI, flower count, and dry mass over a 77-day cycle. Key real finding: the three solutions showed NO statistically significant difference in nasturtium production; Furlani (1997) was simply the cheapest of the three. This means the paper doesn't establish a nasturtium-DERIVED recipe — it only confirms that borrowed lettuce-strength solutions work adequately for the species. If Fred wants to add Nasturtium as a new row, any of the three Table 1 recipes would be a legitimate but genus-borrowed (orange/derived) starting point, not a white/verified nasturtium-specific figure. Not applied — no row exists yet.

Partap, Sharma, HN, Thakur, Verma, Ujala & Bhargava (2023), Journal of Functional Foods 107:105697 — Microgreen: A Tiny Plant with Superfood Potential

Real, full-text-obtained (Fred-supplied PDF) broad literature REVIEW (not a primary trial) covering microgreen market trends, growing conditions, nutritional/phytochemical composition, shelf life, elicitors, and food-omics across dozens of species. No elemental N-P-K, EC, or pH feeding-solution data of its own anywhere in the paper — the one borrowed environmental-range citation (Moraru et al. 2022's pH 6.0–6.8/EC 1.2–1.8 mS/cm) is secondhand (a review citing a review) and not attributable to any primary trial, so not treated as usable corroboration either. The extensive mineral-content tables (e.g. Table 2) are tissue/nutritional-composition data, not feeding-solution targets. Nothing extractable for this calculator.

AB Mix–NPK Fertilizer Combination Effect on Corn Plants Growth Using Nutrient Film Technique (2024), Indonesian Journal of Multidisciplinary Science

Sweet Corn is now a tracked crop in this calculator (see do Moraes Gatti et al. 2023 in Primary Sources for its verified NPK). Re-checked this paper on that basis, but it remains unusable: its own methods state "This study used qualitative research methods. The data collection technique in this research is literature study" — this is a desk-review synthesis of existing corn-fertilization literature, not a primary NFT trial. It reports only qualitative outcomes (increased plant height, leaf number, root development from combining AB mix + NPK fertilizers) with no NPK ppm, EC, or pH figures anywhere in the text. Genuinely no extractable data, not an untracked-crop issue.

Ahn, Noh, Kim & Park (2022), Korean Journal of Agricultural Science 49(3):643-653 — Selection of Appropriate Nutrient Solution for Simultaneous Hydroponics of Three Leafy Vegetables (Brassicaceae)

CITATION FIXED (2026-07-04, per Fred): this entry previously showed a broken placeholder title ("kjoas.org article — 404") because the original kjoas.org direct-article URL (kjoas.org/articles/article/B4dk/) returns a 404. The DOI resolver link above works and resolves to the correct article. This is the SAME source already fully cited and applied earlier in this file (Mustard Greens' verified NPK, 210-31-234) — kept here only as a working-link correction, not a second independent citation.

All previously-pending URLs from this batch have now been analyzed. IntechOpen chapter 70957 (Kumar & Saini) gives a real, complete but generically-sourced NFT strawberry recipe (175-50-210 ppm, EC 1.8–2.0/2.5, pH 5.5–6) — reviewed against this file's Strawberry row, which already carries a far more rigorous multi-stage, multi-study citation set (Yamazaki-based, several independent trial corroborations); not applied. The Nature/basil paper (s41598-2021-91986-7, Khater et al.) turned out to be the SAME paper already cited as the basis for Basil's verified 210-31-234 figure — no new action needed, already applied in a prior session. The Nature/onion ML paper (s41598-2024-82920-8, Dutta et al. 2025) gives only an N-P-K RATIO (10-20-10, then 20-05-05) and EC 1-2.2 mS/cm, pH 6-6.4 — real but generic/non-dedicated targets, and Onion already has a stronger dedicated citation (Kane thesis + published journal); not applied to NPK/EC/pH. UPDATE (per Fred's explicit instruction, later session): this paper's "Smart Hydro Kit" is a real IoT device (ESP32 microcontroller, pH/EC/TDS/temp/humidity sensors, ThingSpeak cloud dashboard) — added to the Automation/IoT/Electronics category above. It also states its EC-from-TDS conversion factor explicitly ("EC can be derived from TDS using a constant factor of 0.64"), independently confirming the ~640 "European" ppm scale is in genuine practical use — supporting evidence for this file's standing TDS-ppm-scale-ambiguity principle (see notes elsewhere). The Nature/thyme paper (s41598-2025-00768-y) is a salinity-stress study using standard, unmodified Hoagland (EC 2.5 baseline, pH target 7, actual 6.7±0.1) purely as its background solution before NaCl stress — real, genus-exact corroboration sitting within Thyme's existing derived pH range (5.5–7.0), but not itself a feeding-target study; not applied. Tandfonline 10.1080/00103624.2026.2636235 was identified via search snippet as Whipker (NC State, 2026) — "Establishing Leaf Tissue Nutrient Standards and Symptomology of Nutrient Disorders in Greenhouse-Grown Rosemary," a real, very recent, hydroponic sand-culture (modified Hoagland's) study — but the abstract page is bot-blocked and full text wasn't accessible this session, so whether it states a feed-solution ppm target (vs. only leaf-tissue sufficiency ranges) couldn't be confirmed; worth revisiting given Rosemary's existing NPK is a container-nursery extrapolation. Tandfonline 10.1080/01904167.2022.2155531 (Velez Carvajal, Diaz Ortiz & Florez Roncancio 2022, Carnation) was bot-blocked this session but has since been obtained via Fred-supplied PDF and fully analyzed — see the dedicated Carnation citation above for its real vegetative/productive-phase fertigation recipe (no longer an unreachable source). The academia.edu duplicates (Marjoram, Onion) and the academia.edu keypass/session URL were not separately fetched since their content is already covered via the direct DOI/PDF sources cited elsewhere in this file, and a signed session-specific keypass URL would not be independently accessible regardless.

Anderson, J.M. (2023), Salve Regina University Hydroponic Center — Bright Lights Swiss Chard Hydroponic Grow Guide

RESOLVED THIS SESSION — full PDF now obtained directly (user-supplied), settling the bot-block noted in a prior session. Real, named, cultivar-exact ('Bright Lights') student hydroponic grow guide ("EGS2/EGS3" system). States: optimal nutrient range 850–950 ppm, optimal pH range 6.0–6.5, target ppm 1250 (internally inconsistent with its own stated "optimal" range — the target exceeds the optimal band by 300+ ppm, an unresolved discrepancy in the source document itself), target pH 6.5, using a 1:1.5 ratio of General Hydroponics FloraGro. NOT USABLE — CORRECTED REASONING this session (per Fred): using a commercial product within an academic/student study is not itself disqualifying; this stays unused because the figures are undifferentiated TDS-ppm (not an elemental N-P-K breakdown or EC in mS/cm) and internally inconsistent with the report's own stated optimal range. Swiss Chard's existing NPK/EC/pH (140-50-200, EC 1.5–2.5 derived, pH 5.5–6.0) remains unaffected; the new pH range (6.0–6.5) only barely overlaps the existing range at its boundary, so it is not used to widen or shift the displayed pH.

Bakirov, Tussupov, Tussupov, Shayea & Shoman (2025), Technologies 13(5):166 — Hybrid ML Model (XGBoost/PCA/Fuzzy Logic) for Beetroot and Tarragon Microgreen Monitoring

A machine-learning/IoT monitoring-system paper — contains sensor architecture and anomaly-detection methodology, no NPK/EC/pH target values for any crop. Not applicable to this calculator.

Clade, Veazie, Boldt, Hicks, Currey, Flax, Walters & Whipker (2025), Applied Sciences 15:9266 — Establishing Leaf Tissue Nutrient Standards and Documenting Nutrient Disorder Symptomology of Greenhouse-Grown Cilantro

(NC State/USDA-ARS/Iowa State/NC Dept. of Agriculture; real hydroponic sand-culture cilantro cv. 'Santo' deficiency trial plus a 463-sample meta-analysis establishing foliar tissue sufficiency ranges for 12 elements — e.g. N 3.94–5.48%, P 0.37–0.77%, K 3.64–6.21% — with photographed deficiency/toxicity symptomology for N, P, K, Ca, Mg, S, B, Fe, and Zn. RE-CHECKED THIS SESSION at direct user request, against the full primary text (not just the abstract/secondary description used previously) — conclusion unchanged. This is a LEAF TISSUE diagnostic standard, not a feeding-solution recipe: it tells a grower what's IN the plant at a healthy concentration, not what to put in the reservoir, and the two are not interchangeable without an uptake-efficiency assumption this calculator's standing rules (Rule 8) prohibit guessing. The trial's own control treatment used a modified Hoagland's solution with P dosed at 30.97 mg/L (~31 ppm) and Ca at 75 mg/L — incidental feeding-side detail, not the paper's tested variable — confirmed on full-text review that no N, K, Mg, or S feeding ppm is stated anywhere in the paper; only leaf-tissue percentages/ppm are reported for those elements (Table 4). Not used to change Cilantro's existing derived NPK/EC/pH; kept as a citation-only reference for anyone diagnosing cilantro nutrient-disorder symptoms by leaf appearance.

Conversa, Bonasia, Lazzizera, La Rotonda & Elia (2021), Frontiers in Plant Science 12:645671 — Reduction of Nitrate Content in Baby-Leaf Lettuce and Cichorium endivia Through Soilless Cultivation System, EC, and Nutrient Solution Management

(University of Foggia, Italy; real, species-exact for Cichorium endivia — covering both var. crispum "endive" and var. latifolium "escarole" — floating and ebb-and-flow baby-leaf trial across four growing cycles. The basic (pre-salinity) nutrient solution is directly stated: N 140, P 50, K 200, Ca 100, Mg 38.4, S 136 mg/L (NO3:NH4 ratio 4:1), EC 2.41 dS/m, with pH "maintained between 5.5 and 6.5" throughout — this pH statement directly matches, and is the basis for promoting to white/verified, this row's existing 5.5–6.5 range (previously derived from a different, less explicit source). NPK differs meaningfully from this row's existing Korea Science-sourced 224-31-390 figure (lower N and K, higher P) — kept as a real, complete, outcome-tested (actual baby-leaf yield/quality measured) corroborating citation rather than overriding, since comparing the relative strength of the two NPK sources needs more scrutiny than this session allows. Real finding of note: salinity (EC raised to 2.5–3.5 via NaCl) reduced nitrate accumulation in lettuce and endive/escarole baby-leaf, with escarole/endive proving more salt-tolerant than lettuce (no significant yield loss up to EC 3.5, vs. clear yield decline in lettuce at EC 3.5 combined with ebb-and-flow) — an EC-vs-nitrate-content tradeoff, not a feeding-target recommendation per se.

Date, Rivero, Tan, Specca, Simon, Salvi & Karwe (2023), Agriculture 13(2):443 — Plasma-Activated Nutrient Solution (PANS) on Hydroponic Sweet Basil

Real, species-exact basil trial, but the variable of interest is plasma pre-treatment of the solution, not the feed recipe itself; base NS is a named commercial blend (YaraLiva Calcinit + Jack's Nutrients) without a full elemental breakdown in the text. Basil's NPK/EC already independently verified elsewhere in this file. Not applied.

de Almeida, Carmona, Cavalcante, Cecílio Filho, de Mello Prado, Flores, Borges & Mauad (2020), Agronomy 10(10):1572 — Nutritional and Visual Diagnosis in Broccoli (Macronutrient Omission Study)

Real, species-exact hydroponic macronutrient-omission/deficiency-symptom study for Broccoli, but the complete-solution (CS) recipe is referenced only as "a modified Hoagland nutrient solution" without the underlying ppm table extractable from what could be fetched. Broccoli's NPK remains the shared, unverified Brassica placeholder in this file — a real upgrade opportunity if this paper's Table 1 can be obtained directly (not just via web fetch).

Dickson & Machesney (2023), North American Bramble Growers newsletter — Substrate and Container-grown Blackberry Research at the University of Arkansas

Real University of Arkansas research-program newsletter update (Dr. Ryan Dickson, Dept. of Horticulture) describing an ONGOING, not-yet-published research initiative into substrate/container long-cane and primocane blackberry production for off-season harvest scheduling. Real and directly on-topic for this calculator's Blackberry row, but contains zero quantitative NPK/EC/pH data — it describes objectives, cultivar-breeding context (UofA Fruit Breeding Program low-chill primocane-fruiting genetics), and collaborators, not a completed trial with results. Nothing to extract; worth checking back for follow-up publications from this same research group.

Fuentes-Peñailillo, Gutter, Vega & Carrasco Silva (2024), Horticulturae 10(1):49 — New Generation Sustainable Technologies for Soilless Vegetable Production

General review of hydroponic systems, sensors, and automation technology; checked for crop-specific NPK/EC/pH data, contains none.

García-Verdugo, Enríquez-del Valle, Campos-Ángeles, Juárez-Hernández, Aragón-Robles, Villegas-Aparicio & Alemán Vargas (2012), Acta Horticulturae 947:245-248 (ISHS) — Nutrient Concentration and N/K Ratio in the Nutrient Solution on Yield and Size of Fruit of Capsicum annuum

RESOLVED THIS SESSION — full PDF now obtained directly (user-supplied), settling the ISHS paywall block from a prior session. Real, peer-reviewed greenhouse trial (Instituto Tecnológico del Valle de Oaxaca, Mexico) on Capsicum annuum 'Chile de Agua', testing Steiner's Universal Solution (1984) at 50/75/100% total-ion strength crossed with three N/K ratio adjustments (N/K unchanged; N‑1me/K+1me; N+1me/K‑1me) applied only after fruit set. The paper directly states the full 100%-strength Steiner recipe: N 166.01, P 31.35, K 277.38, Ca 182.06, Mg 49.08, S 110.89 mg/L, plus micros (Fe 1.33, Cu 0.0051, B 0.077, Zn 0.0375, Mn 0.201, Mo 0.019 mg/L) — a real, complete, standard textbook Steiner formula, not a pepper-specific optimized recipe (same generic-solution caveat already applied elsewhere in this file to Hoagland/Steiner/Sonneveld generic solutions per Rule 2). Real findings, now confirmed via full text: concentration (aliquot %) had a highly significant effect on every measured variable (plant height, stem diameter, leaf count, fruit number, fruit weight), with 100% strength giving the best results across the board (e.g. 4.6 fruit/plant, 63.9g total weight vs. 2.0 fruit/plant, 2.2g at 50% strength); N/K ratio adjustment had NO significant effect on any yield or size variable when tested alone, only a significant interaction with concentration on stem diameter and leaf count. This calculator's Peppers row already carries stronger, dedicated, species-and-stage-specific verified citations (OSU Extension + Haifa Group, 100N-50P-120K ppm, EC 0.8–1.8) — not applied, since a generic full-strength Steiner solution is a weaker, less-targeted source than the existing dedicated pepper recipe.

Gutiérrez Nava, Reyes Espinosa, Serafin Badillo, Martínez Cárdenas & García Piceno (2024) — Técnica de Producción Hidropónica de Planta Medicinal: Una Base para la Salud Colectiva

Compares hydroponic vs. organic technique for milk thistle (Silybum marianum) and thyme (Thymus vulgaris) on plant height/fresh/dry weight — real and genus-relevant for Thyme, but no elemental ppm or EC/pH target values found in what could be retrieved. Not applied.

Gutiérrez-Nava, Casas-Patiño, de la Cruz-Bustos, Rodríguez-Torres, Hernández-Gamundi, Heredia-Sánchez, Vázquez-Juárez, Reyes-Pérez, Carmona-González & Rubí-Sánchez (2026), Preprints.org, doi:10.20944/preprints202605.1700.v1 — Hydroponic Production of the Medicinal Plants Thyme (Thymus vulgaris) and Milk Thistle (Silybum marianum) Under Greenhouse Conditions

Real, complete primary text obtained directly (Universidad Estatal del Valle de Ecatepec, UNEVE, Mexico) — a DIFFERENT paper from the 2024 Gutiérrez Nava et al. citation immediately above (different, mostly non-overlapping author list, different venue, posted 25 May 2026), not a duplicate. Compares an inorganic-substrate-plus-nutrient-solution hydroponic treatment against an organic-substrate/no-solution control for both species, five replicates each, over a 3–4 month growth cycle. States real, dedicated, directly-stated pH and EC targets for BOTH species using the same shared commercial solution (HYDROENVIRONMENT® brand, described only as "a balanced nutrient solution formulated for vegetables in general" — composition NOT disclosed anywhere in the paper, so no NPK figure is usable from this source): pH held 5.5–6.5, EC maintained 1.5–3.0 mS. Hydroponic treatment significantly increased height, fresh weight, and dry weight over the organic control for both species (e.g. thyme +20.9% height, +23.18% fresh weight, +31.68% dry weight; milk thistle +20.68% height, +7.78% fresh weight, +18.04% dry weight). Two possible uses of this real data, both awaiting Fred's decision: (1) Thyme's existing pH (5.5–7.0, orange/derived) could be tightened toward this paper's real 5.5–6.5 — not species-dedicated alone (same solution fed to milk thistle too), so logged as corroboration rather than auto-applied; Thyme's EC (3.6, white/verified via Udagawa's actual EC-optimization trial) is stronger evidence and is NOT displaced by this paper's broader 1.5–3.0 mS range. (2) Milk Thistle (Silybum marianum) is not currently a row in this calculator — this paper would give it real EC/pH but no NPK (the mirror-image of the existing Cress open item, which has real NPK but no EC/pH) — not added unilaterally.

Haifa Group — Complete Recommendation for the Fertilization of Beans (Soilless/Rockwool Nutrition Database)

Real, industry-standard Dutch-glasshouse rockwool recipe for Beans (Phaseolus), sourced to the same Straver 1994 / de Kreij-Sonneveld-Warmenhoven-Straver 1992 lineage already used elsewhere in this file (e.g. Pepper). Directly stated: EC 1.7 mS/cm, N-NH4 13.8 + N-NO3 167.9 = 182 ppm total N, K 215.1, Ca 130.3, Mg 30.4, S (from SO4 108.1) ≈36, P (from H2PO4 121.3) ≈39 ppm. Differs meaningfully from this row's existing figure (35-20-83, EC 2.0–4.0), particularly on K. Kept as a real corroborating/alternative citation rather than overriding — comparing which underlying source is more authoritative for this row needs more scrutiny than this session allows.

Haifa Group — Fertilization of Courgette in Greenhouses (Soilless/Rockwool Nutrition Database)

Real, same Dutch-glasshouse rockwool lineage as above, for Courgette/Squash. Directly stated: EC 2.2 mS/cm, N-NH4 17.3 + N-NO3 223.9 = 241 ppm total N, K 283.5, Ca 145.4, Mg 48.6, S≈40, P≈39 ppm. Squash, Summer's Fruit stage already carries an outcome-validated citation (Pacheco et al. 2023) that explicitly kept this same Haifa figure as a labeled corroborating alternative rather than overriding it — see that citation's own scope note. Not independently re-applied here.

HiMedia Laboratories — PT111: African Violet Maintenance Medium (With Vitamins, Sucrose and IAA, Without Agar)

Real commercial product composition (MS macro/microelements + Linsmaier-Skoog vitamins + sucrose + IAA), but this is a sterile PLANT TISSUE CULTURE medium for micropropagation/callus-and-shoot maintenance of Saintpaulia ionantha, gelled with agar and containing growth regulators and a carbon source (sucrose) — not a hydroponic feeding solution for a mature, photosynthesizing, soil-free plant. Same category exclusion already applied elsewhere in this file to other micropropagation/tissue-culture media (e.g. the Kumar & Saini pineapple citation). Not applicable to African Violet's existing hydroponic EC/pH (OSU Extension-sourced).

"Hydroponic Technology in quality improvement of African violet" (ResearchGate publication 233846140)

This ResearchGate title is almost certainly MIS-TITLED/MIS-TAGGED — its actual abstract describes a BULB crop (bulb fresh weight, 14/10°C and 30/26°C day/night temperature regimes), which does not match African violet's non-bulbous growth habit at all. Strongly suspected to actually be about tulips, hyacinths, or another forced bulb crop. No usable information for African Violet; never re-cite this source for that row.

"Indian Farming Turnip (Brassica rapa) cultivation under modern farming system" (ResearchGate publication 385302959)

Despite the title, the actual visible abstract describes a TOMATO cultivar study (DIBER Orange, Punjab Chhuhara, D.68) at DIBER/DRDO Haldwani, not turnip — appears to be a cross-indexing error between two different articles in the same source collection. The real-looking nutrient figures found alongside this title (N260-P40-K300 ppm, EC ~1800ppm, pH 6-7) could NOT be confidently attributed to turnip given this mismatch, and were not used.

Jensen/Wheeler et al. (1999), Acta Horticulturae 481:87 — Nutrient, Acid and Water Budgets of Hydroponically Grown Crops

Full text obtained (Fred-supplied PDF, 2026-07-12) — corrects the prior note, which had only found a companion abstract describing the recipe generically as "modified ½ Hoagland" with no breakdown. The actual paper (NASA Kennedy Space Center Biomedical Office / Dynamac Corp, atmospherically-closed 20m² CELSS chamber, recirculating NFT) gives a complete Table 1: N 7.5, P 0.5, K 3.0, Ca 2.5, Mg 1.0, S 1.0 mM (Fe 60, Mn 7.4, Zn 0.96, Cu 1.04, B 7.13, Mo 0.01 µM) — converts to 105N-15P-117K-100Ca-24Mg-32S ppm — shared across all four species tested (wheat, soybean, potato, lettuce), EC held at 0.12 S/m (=1.2 mS/cm), pH 5.8±0.2, NO3- as sole N source with dilute HNO3 for pH control. Real, dedicated, directly-stated recipe — but it's ONE shared solution across four very different crops (a life-support/CELSS engineering study optimizing for predictable water/nutrient/acid budgets vs. PAR, not species-specific feeding optimization), and lettuce was explicitly harvested in the vegetative stage before any flowering. Wheat and Soybean have no row in this calculator to attach this to; Potato and Lettuce are both already fully verified from other, more directly-applicable, species-specific sources. Logged for completeness with the full real composition now on record; not used to change any displayed figure.

Jo, Lee, Byeon, Park, Ryoo & Hwang (2022), Frontiers in Plant Science 13:1067713 — Elevated CO2 Concentration Induces Changes in Plant Growth, Transcriptome, and Antioxidant Activity in Fennel (Foeniculum vulgare Mill.)

Real, peer-reviewed, species-exact (Foeniculum vulgare), genuinely hydroponic (deep-flow-technique, rock-wool cubes, Sangji University, Korea) trial — the eCO2/light-intensity manipulation is the point of the study, but the nutrient solution itself is a fixed background condition, directly and completely restated (not merely named — clears Corrective Lesson #6): 606 mg/L KNO3, 115 mg/L NH4H2PO4, 236 mg/L Ca(NO3)2·4H2O, 246 mg/L MgSO4·7H2O, plus micronutrients (22.6 mg/L Fe-EDTA, 2.9 mg/L H3BO3, 1.8 mg/L MnSO4·4H2O, 0.2 mg/L ZnSO4·7H2O, 0.08 mg/L CuSO4·5H2O, 0.03 mg/L (NH4)6Mo7O24·4H2O — originally developed for water dropwort/Oenanthe stolonifera per the paper's own cited source, but directly applied and tested on fennel here). Converts to 126N-31P-234K ppm (also Mg 24, Ca 40, S 32 ppm). PROMOTES Fennel's NPK to white/verified at 126-31-234 ppm, replacing the prior orange/derived 150-31-210 figure — a straightforward gap-fill (Corrective Lesson #3). EC was measured (not fixed) at ~1.53–1.54 mS/cm under normal light conditions (drifting higher at night/under eCO2) — real, but DISAGREES with Fennel's already-verified EC (1.0–1.4, from a different source) — per Corrective Lesson #12, logged as a real, not-applied alternative, not overriding the displayed EC. No fixed pH target stated (only a described dark/eCO2-driven trend) — Fennel's already-verified pH (6.4–6.8) is unaffected.

Kane, M. (2011), Salve Regina University Hydroponic Center — Propagation System Manual

RESOLVED THIS SESSION — full PDF now obtained directly (user-supplied). Confirmed as expected: this is purely an equipment/construction/procedure manual (materials list, assembly instructions, timer settings, cleaning/safety protocols for the physical propagation system) — not a crop-specific nutrient document. The only nutrient figures given are generic propagation-STAGE defaults applied to ALL seedlings regardless of species (800 ± 50 ppm TDS and pH 5.8–6.2 during the first two weeks of germination, using the same General-Hydroponics-adjacent "Future Growing Tower Tonic Mix A/B" 2-part product), not a species-specific target for any crop tracked in this calculator. Not applicable to any row.

Karatsivou, Elvanidi & Katsoulas (2025), Horticulturae 11(10):1168 — Three-Level Cascade Soilless System (Tomato → Mint/Peppermint → Lemon Balm/Sea Fennel) Under Saline Conditions

Real, species-exact for Mint, Peppermint, and Lemon Balm, but all EC/nutrient values shown are deliberately escalating salinity-stress treatments (9–11+ dS/m by design), not standard feeding targets. Does not resolve the open Lemon Balm NPK conflict (Urmia/Safaei vs. Son et al.) flagged elsewhere in this file. Not applied.

Kawatra/Kou et al. lineage — real hydroponic Buckwheat (Fagopyrum esculentum/tataricum) studies found, no usable feed recipe

Deep search this session for Microgreen - Buckwheat found several real, hydroponic, species-exact studies (phytochemical-profile-by-phenological-stage trial citing a Kawatra et al. 2023 protocol; a tellurium-doped ZnO nanoparticle elicitor trial on buckwheat microgreens/sprouts; various sprout-biofortification/probiotic-yeast studies) — none disclose an actual nutrient-solution N-P-K/EC/pH figure in the accessible text; they describe "the nutrient solution was changed every three days" or similar without stating composition. Buckwheat could not be promoted from the generic placeholder this session; remains open for a future session with fuller PDF access. Microgreen - Chia AND Microgreen - Amaranth: a real SciELO Mexico trial (LED-light study on Amaranth AND Chia microgreens together, 50%-strength Steiner solution) gives a complete recipe — N168-P31-K273-Ca180-Mg48-S130 ppm, micros Fe3/Mn1/B0.5/Cu0.1/Zn0.1 — states no pH. PER FRED'S EXPLICIT INSTRUCTION (2026-07-11): NPK and pH don't have to move together — the real, directly-stated NPK figure was applied on its own (promoted white/verified, 168-31-273) to BOTH rows, replacing Chia's prior generic placeholder and Amaranth's prior 100-20-97 figure. That prior Amaranth NPK turned out, on checking, to have NO citation anywhere in this file backing it at all — despite being marked white/verified (npkDerived:false) — a genuine inconsistency between the flag and the evidence, caught when Fred asked what actually supported it.

Piña-Moreno, Leyva-Ovalle, López-Espíndola, Contreras-Oliva, Ramírez-Rivera & Herrera-Corredor (2025), Agrociencia 59(5):3439 — Optimized Substrate Formulation Using Industrial Instant Coffee Residue for Growing Amaranth and Chia Microgreens

Real, peer-reviewed, PDF-obtained (Fred-supplied, 2026-07-11), species-exact hydroponic trial on Amaranth AND Chia microgreens together (Colegio de Postgraduados/Universidad Veracruzana, Mexico) — primarily a SUBSTRATE study (7 sand/sawdust/coffee-residue mixtures; 100% sand won on stem diameter, root length, and hypocotyl height; coffee residue alone was the weakest substrate), with the nutrient solution held constant as a background condition across all substrate treatments, not the tested variable. That fixed nutrient solution (Table 3, a commercial "SOLUPONICS® STANDARD A+B UNIVERSAL" product with full composition directly disclosed, not merely named — clears Corrective Lesson #6): NO3-N 15 + NH4-N 1 = 16 mmol/L total N, PO4-P 2 mmol/L, K+ 7 mmol/L, Ca2+ 6.23 mmol/L (nutritional contribution, includes background water Ca), Mg2+ 2.25 mmol/L, SO4-S 2 mmol/L — converts to 224N-62P-274K ppm (also Ca 250, Mg 55, S 64 ppm). pH directly stated: adjusted to 6.0 with nitric acid. EC: paper states "2300 mS cm⁻¹," which is implausible at face value (that would be an absurdly concentrated brine, not a microgreen feed) — but the paper's own stated osmotic potential (-0.083 MPa) confirms the intended value is 2.3 mS/cm (dS/m): the standard EC-to-osmotic-potential approximation (OP ≈ -0.036 × EC) gives -0.036 × 2.3 = -0.083 MPa, an exact match — so this is read as a µS/cm-vs-mS/cm unit-labeling error in the original paper, not a real 2300 mS/cm target. APPLIED: promoted Amaranth's and Chia's EC (2.3, replacing the old unbacked 1.0 shared with 5 other unrelated microgreen rows) and pH (6.0, replacing Amaranth's unbacked 5.5–6.5 and Chia's unbacked 5.9) to white/verified for both rows — no competing real, dedicated source was found for either field on either crop. NPK FLAGGED AS AN OPEN 2-WAY CONFLICT, NOT APPLIED: this paper's real NPK (224-62-274) disagrees with the SciELO 50%-Steiner paper's real NPK (168-31-273, currently displayed) — per Corrective Lesson #12, a real source disagreeing with an already-verified figure needs Fred's judgment, not an automatic override. Displayed NPK unchanged at 168-31-273 pending that choice.

Korkunç, Ari Engin, Zaman, Bakırdere & Karakuş (2025), Scientific Reports 15:43905 — Selenium Speciation Analysis for the Investigation of Selenium Uptake for the Hydroponically Cultivated Garlic Samples

Real hydroponic garlic selenium-enrichment trial with genuine speciation chemistry and uptake-rate data, but never discloses the nutrient solution's N-P-K composition (states only "0.50 g of plant nutrient," no brand or analysis given), states no EC, and states no growing-medium pH (only HPLC mobile-phase pH 6.0 and an unrelated enzymatic-extraction buffer pH 7.5, neither of which describes the plant's growing medium). 14-day sprout-to-harvest cycle, terminated before bulbing — too early-stage to inform Garlic's Bulb or Mature cells even if NPK had been disclosed.

Leng, Stambolie & Bell (1995), Livestock Research for Rural Development 7(1):3 — Duckweed: A Potential High-Protein Feed Resource for Domestic Animals and Fish

Real review (Centre for Duckweed Research & Development, University of New England) combining literature synthesis with the Centre's own unpublished trial data (Leng, Bell & Stachiw 1994; Stambolie & Leng 1994). General management guidance repeats what's already cited elsewhere in this file (pH 6–8 tolerated, best growth 6.5–7.5, target pH 6–7 for management) — not new. What IS a real, additional data point: Table 3, from the Centre's own trial (Spirodela sp. grown on diluted piggery effluent), shows crude protein (N×6.25) increases with water N concentration up to a plateau, with the ~40% max-protein band clustering at 7–12 mg N/L — i.e. a real, dedicated, LOWER N figure than any of the standing Duckweed NPK conflict's other points (prior 24-3-25 placeholder, Jin et al.'s 4× Hoagland finding, Petersen et al.'s 14-3-36 — the last of which is now Duckweed's displayed, white/verified NPK per Fred's 2026-07-11 choice). A real, still-lower alternative N figure, logged for the record — not applied, since the conflict was resolved in Petersen's favor. P: Table 4 shows tissue-P response to water-P (0–3 mg P/L tested) — a bioaccumulation-capacity dataset, not a stated feeding target, so not usable as a P figure. Not applied — logged alongside the existing conflict for Fred's eventual choice.

Luz, Silva, Haber, Pirolla & Doro (2009), Revista Ciência Agronômica 40(4):610-616 — Hydroponic Cultivation of Smooth and Curly Chicory and Almeirão at Different Nutrient Solution Concentrations

Real, species-relevant NFT trial (chicória lisa/crespa, almeirão) testing the generic Furlani et al. (1999) solution at 50–125% strength — no growth differences found across the range, so 50% strength recommended for cost savings. No distinct elemental ppm breakdown beyond the already-known Furlani baseline; not a new recipe. Not applied.

Ma, Ban, Yu, Li, Li, Jiang & Xie (2019), Agronomy 9(5):262 — Urea Addition Promotes the Metabolism and Utilization of Nitrogen in Cucumber

(Gansu Agricultural University/Guizhou Academy of Agricultural Science/Chinese Academy of Agricultural Sciences; real, species-exact coir-substrate cucumber trial (cv. 'Zhongnong 26') comparing nitrogen FORM, not amount — 6 treatments all held at a fixed 14mM total N, varying the ratio of ammonium/nitrate/urea (100% NH4, 100% NO3, 100% urea, and three 50/50 mixes). Found 50% NO3 + 50% urea gave the highest dry matter, yield, and leaf nitrogen-metabolism enzyme activity (GOGAT, GS, nitrate reductase, urease) of all six treatments, with pure ammonium performing worst (ammonia-toxicity symptoms). This is a nitrogen-FORM optimization study at one fixed total-N level, not an N-P-K-EC-pH feeding recipe — no P, K, EC, or pH figure is given anywhere in the paper. There is no Cucumber row's chemistry breakdown by N-form in this calculator (NPK is tracked as elemental totals regardless of which salt supplies the N), so this finding has no field to attach to even though Cucumber is otherwise fully verified. Kept as a real, species-exact citation for if this calculator ever adds N-form-specific guidance.

Mareko & Gurr (2016), Journal of Health Disparities Research and Practice 9(5):46 — Sodium Chloride Affects Growth in Taro

Real, genus-exact (Colocasia esculenta cv. 'Samoa 2') hydroponic salinity trial with seven real EC levels tested (0.34–8.99 mS/cm via 0–80mM NaCl) — full-text PDF obtained directly and read in full (user-supplied). The publication's own abstract states its central finding as a literal, unfilled placeholder on every page it appears: "The NaCl tolerance threshold... for taro variety Samoa 2 was found to be at x mM NaCl solution, equivalent to an EC value of x mS/cm." This exact placeholder text appears verbatim in the abstract, the standalone abstract page, and the running head of the full article page — it was never corrected before publication. The rest of the paper (methods, the seven tested EC levels, the wetland field-salinity context) is real and complete; only the specific numeric conclusion the paper sets out to report is missing from the source itself — no relevant usable information could be extracted. Not used for Taro's EC.

Martins, Santos Júnior, da Silva Júnior, Silva & Medeiros (2019), Ciência e Agrotecnologia 43:e023418 — Production of Parsley in Hydroponic Conditions Under Isosmotic Brackish Nutrient Solutions

Real, species-exact (Petroselinum crispum cv. 'Graúda Portuguesa') hydroponic salinity trial (UFRPE, Brazil) — a factorial imposed-salinity design (six isosmotic ECns levels, 1.7–6.7 dS/m, crossed with four salt types: NaCl, CaCl2, MgCl2, KCl), not a feeding-target optimization. The baseline/lowest ECns (1.7 dS/m, from an unstressed 1.58 dS/m nutrient solution diluted in municipal water) is real corroboration sitting almost exactly at Parsley's existing verified EC (1.6) — not a conflict, just independent confirmation from a different, genus-exact source. No elemental NPK breakdown given in the abstract. Not applied — Parsley's displayed NPK/EC/pH unchanged.

Melo & Santos (2011), Horticultura Brasileira 29(4) — Growth and Production of Nasturtium Flowers in Three Hydroponic Solutions

Real, species-exact (Tropaeolum majus), full NFT hydroponic trial (UFSM, Brazil) — three complete named nutrient solutions given in g/1000L using standard salts (Ca(NO3)2, KNO3, NH4H2PO4, KH2PO4, KCl, MgSO4·7H2O plus micronutrient sulfates/borate/molybdate) across an 11-date growth curve. Genuinely on-topic for a Nasturtium row, but the exact per-salt gram quantities were not retrievable from available search snippets/abstract this session (full-text PDF blocked by bot detection) — logged as a real, promising lead for a future session with direct PDF access, not applied. A separate real, dedicated MDPI trial (Agronomy 11(2):363, node-position/EC cutting-rooting study) found EC 1.0 dS/m best for nasturtium cutting propagation specifically — a different growth phase (rooting, not vegetative/microgreen growth), so also not applied to Microgreen - Nasturtium's EC.

Nghiem, Hoang, Chu & Ha (2023), Proceedings of International Workshop "Sustainable Management and Development of Environment and Natural Resources," doi:10.15625/vap.2023.0009 — Effects of Nitrogen, Phosphorus, Potassium Content on Growth and Essential Oil Properties of Rosemary Grown by Semi-Hydroponic Method in Net-House

Real, peer-reviewed, species-exact (Rosmarinus officinalis) semi-hydroponic trial (Vietnam National University Hanoi) — drip-irrigated nutrient solution onto a coco-peat/sand/rice-husk/vermicompost/cow-manure substrate, four directly-stated N-P-K formulas tested: F1 100-50-150, F2 150-50-250, F3 100-100-200, F4 150-100-200 ppm. F4 gave the highest plant height, branch count, and fresh/dry biomass of the four (49.6cm/60.25 branches/1.13kg/0.25kg) after 4 months, making it the study's own best-performing recipe; F3 and F4 also gave the highest essential-oil content (1.96%/1.93%) alongside F1. PROMOTES Rosemary's NPK to white/verified at 150-100-200 ppm (the F4 winning formula), replacing the prior orange/derived 175-38-145 figure — a straightforward gap-fill (Corrective Lesson #3), since no real dedicated NPK source existed for Rosemary before this. EC/pH not stated in this paper (drip volumes given in mL/plant/day, not EC/pH readings) — Rosemary's EC and pH remain unchanged, still orange/derived.

Miranda, Quiroz & Salazar (2000), Hidrobiológica 10(1):7 — Cadmium and Lead Removal from Water by Duckweed (Lemna gibba)

Real duckweed study, but about heavy-metal (Cd/Pb) phytoremediation and toxicity, not nutrient feeding — a diluted (1:40) Hoagland solution is used only as the growth medium background. Not applicable.

Moreno, López-Berenguer, Martínez-Ballesta, Carvajal & García-Viguera (2008), J Sci Food Agric 88:1472-1481 — Basis for the New Challenges of Growing Broccoli for Health in Hydroponics

Real, peer-reviewed, species-exact ('Marathon' broccoli) hydroponic greenhouse trial (CEBAS-CSIC, Spain), but the study's purpose is phytochemical (glucosinolate/vitamin C/flavonoid) enrichment via NaCl abiotic stress and foliar elicitors (methionine, tryptophan, chitosan), not nutrient optimization. Feeding is stated only as "continuously aerated Hoagland nutrient solution... replaced completely every week" — same naming-without-restating-the-numbers situation as this file's standing rule on named-formula citations. No extractable NPK/EC/pH figure. Not applied; same shared Brassica placeholder gap noted in the de Almeida citation above remains open.

Ogbuehi, Loretan, Bonsi, Hill, Morris, Biswas & Mortley (1991), NASA Technical Reports Server 19910018751 — Effect of Biweekly Shoot Tip Harvests on the Growth and Yield of "Georgia Jet" Sweet Potato Grown Hydroponically

(Tuskegee University G.W. Carver Agricultural Experiment Station/NASA CELSS program; real, species-and-cultivar-exact NFT trial testing biweekly shoot-tip harvesting for use as vegetable greens. Nutrient solution described only as "a modified half Hoagland solution," pH maintained at 6.0 via NaOH/H2SO4 — no elemental ppm table given anywhere in the paper, only anion/cation uptake-rate trends and yield weights. Real finding: harvesting shoot tips biweekly did not significantly affect storage root number or fresh/dry weight compared to unharvested controls, so shoot tips can be used as a dual food source without yield penalty. Not usable as a number source for Sweet Potato's NPK/EC/pH — no recipe is disclosed. Kept as real, on-topic, genus-and-cultivar-exact citation for reference only.

Petersen, Demann, Restemeyer, Olfs, Westendarp, Appenroth & Ulbrich (2022), Plants 11(8):1010 — Light Intensity/Spectrum on Duckweed (Lemna minor, Wolffiella hyalina) in an Indoor Vertical Farm

Real, species-exact, and gives a complete stated recipe (EC 0.6 mS/cm; ≈14N-3P-36K ppm). PER FRED'S EXPLICIT CHOICE (2026-07-11), this figure is now Duckweed's displayed, white/verified NPK (see the fuller note on this same paper in Primary Sources above) — no longer an unresolved conflict against the prior 24-3-25 placeholder.

Pradana (2017), Sarjana Thesis, Universitas Brawijaya — Temperature Control in Shallot (Allium cepa var. Aggregatum) Cultivation in a DFT Hydroponic Plant Factory

Real, species-exact (Allium cepa var. Aggregatum = Shallot) Indonesian thesis, but the tested variable is temperature (25/28/31°C), not nutrient solution — EC (2.5 mS/cm) and pH (6.0–7.0) are stated only as fixed constants, not derived/optimized values, and no NPK is given. The thesis's own conclusion notes the plant-factory-grown shallots underperformed conventional soil-grown controls. Real but weaker evidence than needed to override Shallot's existing EC (1.4–1.8) — logged as a real data point (EC 2.5 sits above the current range) without changing the display.

Safaei, Alirezalu, Noruzi & Alirezalu (2024), BMC Plant Biology 24:968 — Phytochemical and Morpho-Physiological Response of Melissa officinalis L. to Different NH4+:NO3- Ratios Under Hydroponic Cultivation

Real, species-exact (Melissa officinalis = Lemon Balm) floating-culture trial from Urmia University — the same institution behind one side of this file's already-open Lemon Balm NPK conflict (Urmia/Safaei 210-61-277 vs. Son et al. 354-186-420), and likely a companion/follow-up study by an overlapping author group. Table 1 states a complete base recipe held constant across all NH4:NO3 ratio treatments, but the actual ppm/mM values were not extractable from what could be fetched (rendered as an image/table, not text). Real finding: the 0:100 (all-nitrate) treatment gave the highest biomass, while 75:25 (mostly ammonium) gave the highest antioxidant activity and dry matter — a real yield-vs-quality tradeoff. Does not resolve the existing Lemon Balm conflict since the base NPK figure isn't extractable; flagged as a likely-related source if the full table can be obtained in a future session.

Sakamoto & Suzuki (2020), Agronomy 10(11):1708 — Effect of Nutrient Solution Concentration on the Growth of Hydroponic Sweetpotato

(Kindai University, Japan; real, species-and-cultivar-exact ('Narutokintoki') vermiculite-based hydroponic trial, two experiments testing EC 0.8/1.4/2.6 dS/m and EC-switching schedules. Full stated recipe (OAT house 1:2 fertilizer, 3:2 ratio): N 260, P2O5 120, K2O 405, CaO 230, MgO 60 mg/L — converts to N260-P52-K336-Ca164-Mg36 ppm. Real finding: shoot and storage-root growth increased with EC up to 2.6 dS/m (the highest level tested), with no upper plateau found within this range; switching from high-to-low EC partway through cultivation induced heavy leaf abscission (likely N/P-deficiency-triggered), while low-to-high EC did not. This is the companion root-type-cultivar trial already referenced in this calculator's existing Sweet Potato citation (see the Kano et al. 2021 entry above, which is the basis for Sweet Potato's verified NPK/EC/pH) — confirmed as a broadly similar-shaped recipe, consistent with the existing citation's own description. No changes needed; already accounted for.

Savini, Graziano, Bertoldi, Soppelsa & Andreotti (2016), Acta Horticulturae 1117:335-340 — Dynamics of Nutrient Uptake in Raspberry Plants

(Società Cooperativa Sant'Orsola/Fondazione E. Mach/Free University of Bozen-Bolzano, Italy; real long-cane greenhouse trial, cvs. 'Tulameen' and 'Vajolet', testing three complete fertigation solutions of differing EC/N-P-K — gives full, genuinely complete, directly-stated N-P-K-Ca-Mg-S ppm figures for all three treatments, e.g. Solution A: 340N-54P-173K ppm at EC 1.5 mS/cm. Would otherwise be an excellent direct same-genus source — but the paper's own methods state the plants were "transplanted in 6.5-L pots containing SOIL, peat and coconuts fibre," and this calculator's standing substrate definition explicitly disqualifies any medium described as containing garden soil, even when mixed with inert components like peat or coir. Not used for any NPK/EC/pH value on Raspberry's row. Worth noting for context only: lower-N Solution B reduced yield in 'Tulameen' specifically and increased fruit firmness and total phenolic content in both cultivars — a real finding, just from a disqualified growing system.

Schloemann, UMass Extension — Raspberry Production: Guidelines for Greenhouse Growing

Real, species/cultivar-exact (Rubus idaeus 'Tulameen') container-and-drip-fertigation guide (not true hydroponic NFT/DWC), directly stating a complete weekly feed: 2.46 g/gal 5-11-26 (Peter's Hydrosol) + 0.26 g/gal ammonium nitrate + 1.23 g/gal calcium nitrate, giving 100 ppm N (88 as NO3-N, 12 as NH4-N), computed here to ≈100N-31P-140K ppm; diluted to 50 ppm N once flowering begins. Real and complete, but SUPERSEDED — this file's Raspberry row already carries a stronger, outcome-validated, true-hydroponic staged citation (Bazangeya et al. 2025, indoor vertical-farm trial measuring actual fruit yield by growth stage). Not applied.

Sommer, Camargo, Bicca, Raasch, Peil & Schuch (2016), Agronomy Science and Biotechnology 2(2):85-91 — Blackberry and Raspberry Seedlings Growth Under the Soilless Cultivation System

(Universidade Federal de Pelotas, Brazil; real soilless system comparing micropropagated blackberry 'Xavante'/'Tupy' and raspberry 'Heritage'/'Fall Gold' mini-cuttings — soilless flowerpot system (sand-filled, daily nutrient solution) significantly outgrew the conventional bagged-substrate system (H. Decker substrate, fertilized every 15 days) on aerial part length, lateral shoot count, and fresh/dry biomass for both genera. This is a PROPAGATION-stage trial (rooting and establishing mini-cuttings from tissue culture, 0–120 days) measuring growth response to feeding FREQUENCY, not a mature-plant feeding-concentration recipe — the paper states only that its nutritive solution "contains macronutrients and micronutrients formulated according to the needs of blackberry and raspberry cultures" (citing Sommer's own unpublished 2015 dissertation for the actual composition), with no N-P-K/EC/pH figures disclosed anywhere in this paper itself. Not usable as a number source for either Raspberry or Blackberry's existing figures — kept as a real, genus-exact citation establishing that soilless propagation itself outperforms conventional substrate propagation for both genera.

Subandi, Muntafi, Frasetya, Sarbini & Kusnawan (2022), AIP Conference Proceedings 2563:040016 — The Effect of Various Nutrient Hydroponic Formulation on Growth and Yield of Three Varieties of Common Bean (Phaseolus vulgaris L.) on Hydroponic Drip Irrigation System

(State Islamic University Sunan Gunung Djati Bandung, Indonesia; real, peer-reviewed, genus-exact common bean drip-irrigation trial, three Balitsa cultivars crossed with four named nutritional formulas — f1 Sutiyoso (2006), f2 Aroca (2006), f3 Chaoui et al. (1997), f4 Hoagland (1950). CONFIRMED, with the full PDF now in hand, matching a prior session's abstract-only finding: the paper cites each formula by author/year but never reprints any of their actual N-P-K-ppm compositions anywhere in its own text or tables — only relative outcomes are reported (e.g. f1/Sutiyoso gave the tallest plants, widest leaf area, and highest root-shoot ratio of the four; f1 also had the highest stated K content among the four at 450 ppm, mentioned in passing while discussing leaf area, but P/N/Ca/Mg are never given even for f1). Per this calculator's standing Rule 5, a single incidental K figure with no N or P alongside it cannot be used to construct or complete an NPK triplet. Green Beans/Beans already carry independently-sourced, complete, white/verified hydroponic recipes elsewhere in this file; this paper does not supersede or add to them. No values changed.

Sundari, Pauzy, Firmansyah, Arif & Purba (2025), Agro Bali 8(3):1051-1068 — Comparative Study: Internal Marketing Value of Shallot Hydroponic Performance Using NFT vs. DFT Across Two Growth Periods

Real, species-exact (Allium cepa var. aggregatum) commercial NFT/DFT hydroponic case study (P4S Galih Jaya, Indonesia), primarily a financial/internal-marketing comparison, but its methods directly state a staged TDS schedule (400 ppm at shoot emergence → 800 ppm wk 2 → 1200 ppm wk 3-4 → 1600 ppm wk 5+) and pH 5.5–6.7, "measured before and after adding nutrients using a pH meter." PROMOTES Shallot's pH to white/verified at 5.5–6.7, since this range brackets and corroborates the existing 6.0–6.5 figure and, combined with the Pradana thesis above (6.0–7.0 constant), gives two independent real, species-specific sources agreeing on essentially the same range. EC/TDS NOT applied: the staged 400–1600 ppm figure is TDS in ppm, not EC in mS/cm, and converting between the two requires picking one of three competing, genuinely-in-use hydroponic ppm scales (~500 ppm/mS/cm "NaCl," ~640-650 "European," ~700 "442/KCl," used inconsistently across regions and even across meter manufacturers within the same region) — this source never states which one its meter uses, so any conversion would be an unstated assumption, not a real number. (The calculator's existing 1.4–1.8 mS/cm EC was already left unchanged against a similarly-styled fixed-constant source from the Pradana thesis, per the note above — kept consistent with that precedent.) NPK unaffected — no N-P-K breakdown given, only a generic "AB Mix" macronutrient list.

Torres Mendonça, Silva, Soares, Soares, Nunes Oliveira, Gheyi, Lacerda, Azevedo & Lima (2022), Agriculture 12(10):1687 — Salicylic Acid and Salt Stress on Hydroponic Okra

Real, species-exact NFT trial giving a real salinity threshold (2.54 dS/m) — broadly consistent with, and corroborating, Okra's already-verified EC range elsewhere in this file. No NPK given (generic Hoagland reference only). Not applied.

Toyosumi, Souza & Ledo (2023), Revista Brasileira de Engenharia Agrícola e Ambiental 27(9):682-689 — Recirculation Intervals of Nutrient Solution in Hydroponic Acclimatization of Banana Seedlings

Real, species-exact (banana cv. 'Prata-Anã') study from a micropropagated-seedling biofactory (Cruz das Almas, Bahia) — but tests nutrient-solution RECIRCULATION INTERVAL timing (0.25 to 23.75 hours) during the post-tissue-culture acclimatization/hardening-off phase, not NPK/EC/pH concentration. Real finding: intervals up to 0.75h had no effect on early growth, but longer intervals reduced growth, especially in hotter conditions — an operational/scheduling finding, not a feeding-target one. Not applicable to Banana's displayed NPK/EC/pH (now CN102992835A-patent-sourced, see above) — logged as adjacent real context on banana's broader hydroponic nursery handling.

Tran, Heiman, Lydy & Kissoon (2023), Plants 12(5):1104 — Silver Nanoparticle Toxicity on Lemna minor at Different Frond Densities

Real, species-exact duckweed trial, but the subject is silver-nanoparticle toxicity and frond-crowding effects, not nutrient feeding. Uses diluted (2.5%) Hoagland for AgNP stability reasons specific to the toxicology protocol. Its dilution-series result (25% Hoagland outperformed all more-dilute options) mildly corroborates the "duckweed tolerates higher-than-typical concentration" direction of the open Duckweed conflict, but doesn't resolve it. Not applied.

Truffault, Ristorto, Brajeul, Vercambre & Gautier (2019), Agronomy 9(2):80 — To Stop Nitrogen Overdose in Soilless Tomato Crop: A Way to Promote Fruit Quality Without Affecting Fruit Yield

(CTIFL/INRA, France; real, species-exact, year-long rockwool soilless tomato trial (cv. 'Clodano') comparing standard 16mM N to a reduced 5mM N supply. Found marketable yield, leaf photosynthetic activity, and plant architecture were NOT significantly affected by the 3-fold N reduction — but fruit quality improved under low N: higher sugar:acid ratio (citric/malic acid both decreased more than sugars did), more unmarketable fruit under the high-N treatment, and no change in vitamin C. This is a feeding-RATE finding (how much N, not a full N-P-K-EC-pH recipe) and an agronomic-outcome study (yield/quality tradeoffs), not a source of new NPK/EC/pH figures. Tomato's existing verified Fruit-stage N target in this calculator (190 ppm N, via the Jensen/UA-CEA recipe) works out to roughly 13.6 mM — within the paper's stated "usual practice" range of 13–16mM N, i.e. the higher-N end this paper found unnecessary for yield but with a fruit-quality cost. Kept as real corroborating context on the existing Fruit-stage N target's headroom, not used to change the displayed figure.

Vanacore, El-Nakhel, Modarelli, Rouphael, Pannico, Langellotti, Masi, Cirillo & De Pascale (2024), Plants 13(20):2852 — Lettuce and Curly Endive in Hydroponic vs. Aquaponic Systems

Real, species-exact for Lettuce and Endive, but the hydroponic control uses generic "half-strength Hoagland" without a stated elemental ppm breakdown in the text; Table 6's actual mineral concentrations weren't extractable from what could be fetched. Not applied.

Voutsinos-Frantzis, Ntatsi, Karavidas, Neofytou, Deriziotis, Ropokis, Consentino, Sabatino & Savvas (2022), Agronomy 12(9):2214 — K:Ca:Mg Ratio and EC Effects on Cichorium spinosum (Spiny Chicory)

Real, floating-raft trial, but Cichorium spinosum (spiny chicory/stamnagathi) is a different species than this file's Chicory row (Cichorium intybus) — no NPK given, only EC (2.4/3.6 dS/m) and K:Ca:Mg ratio, with no significant yield effect found either way. Not applied.

Wheeler, Mackowiak, Sager, Knott & Hinkle (1990), American Potato Journal 67:177-187 — Potato Growth and Yield Using Nutrient Film Technique (NFT)

(Bionetics Corp./NASA Kennedy Space Center CELSS program; real, complete, species-exact 112-day recirculating NFT trial, cvs. 'Denali' and 'Norland', full stated starting recipe (mM): N 7.5, P 0.5, K 3.0, Ca 2.5, Mg 1.0, S 1.0 (converts to N105-P16-K117-Ca100-Mg24-S32 ppm), pH controlled to 6.0 via dilute HNO3. This calculator's Potato row already carries a real, genus-exact NASA/Dynamac Hoagland's-based citation (210-31-235 ppm, EC 1.2, pH 5.8) from a longer 418-day trial — this Wheeler et al. paper is a separate, earlier NASA CELSS potato NFT study with a different (lower-strength) recipe. Real finding: tuber yields were comparable to solid-media controlled-environment studies, with some tubers showing superficial "salt burn" injury from solution evaporating on the tuber surface. Kept as real corroborating/comparative context; not applied — Potato's displayed NPK/EC/pH unchanged, since the existing citation is the longer, more directly applicable trial.

Whitehead, A.J. (1987), University of British Columbia MSc Thesis — Experimental Culture of Duckweed (Lemnaceae) for Treatment of Domestic Sewage

Real duckweed-culture thesis (Bio-Resource Engineering, UBC), genuinely on-topic for this row — but its Table 1 "Summary of environmental requirements of duckweeds" (pH optimum 4.5–7.5, min 3.5, max 8.5; N optimum 5 mg/L "only one value reported"; P optimum 0.031–0.31 mg/L; K optimum 2 mg/L "only one value reported") is explicitly captioned "adapted from Stephenson, et al., 1980" — i.e. Whitehead is relaying someone else's compiled figures in a literature-review table, not presenting his own independently measured trial result for these specific numbers. Per this file's standing rule (a source naming/citing another study's values without those being its own finding doesn't qualify as an independent academic source), this doesn't directly clear the bar as-is. Flagged as a lead: the real primary source to track down, if a future session wants to chase it, is Stephenson, R.J. et al. (1980) — not used to change Duckweed's displayed NPK/EC/pH. Separately of note (own thesis content, not the borrowed table): Whitehead's own experimental chapters concern duckweed for sewage-nutrient removal rather than an optimized hydroponic feeding recipe, so even his original work here isn't a feed-target source either.

Wild, Wilson, Stur & Shelton (1993), IGC Proceedings — Shading Increases Yield of Nitrogen-Limited Tropical Grasses

Real International Grassland Congress proceedings paper, but it is field-grown tropical pasture/forage grass agronomy (grazing land N-cycling and litter breakdown under tree shade), not a recognizable vegetable, herb, or fruit crop tracked anywhere in this calculator, and not hydroponic. No applicable row exists for it.

Yang, Feng, Liu, Lv, Zheng & Tan (2021), Biomolecules 11(1):93 — Research Progress of a Potential Bioreactor: Duckweed

Real, genus-exact (Lemnaceae) review, but entirely about duckweed as a transgenic protein-expression "chassis plant" — genome sequencing, chloroplast/mitochondrial genome assembly, tissue-culture transformation protocols (callus induction media using 2,4-D, sucrose/sorbitol, kinetin as plant-tissue-culture growth regulators, not a fertilizer feeding recipe), and yields of recombinant vaccines/antibodies/industrial enzymes (e.g. interferon-α2, human growth hormone, aprotinin). No NPK, EC, or pH figure for cultivating ordinary (non-transgenic) duckweed appears anywhere in this paper — checked specifically, contains none. Does not change Duckweed's existing derived NPK/EC/pH.

Zhao, Sofkova-Bobcheva, Cartmill, Hardy & Zernack (2024), New Zealand Journal of Crop and Horticultural Science 52(3):280-297 — Comparative Evaluation of Pumice as a Soilless Substrate for Indoor Rubus idaeus L. Cultivation

(Massey University, New Zealand; real hydroponic dwarfing-raspberry trial, cvs. sel.8/sel.110, comparing coir/pumice/pumice-flax/pumice-coir substrates — primarily a substrate physical-properties study (bulk density, porosity, water-holding capacity) and fruit-quality/yield comparison, not a nutrient-solution trial; citation-only for NPK, as none of the substrate treatments varied feed composition. However, the Methods section discloses the actual staged commercial nutrient program used to grow all treatments ("Level 3 Custom Bathed Nutrition," Pure Hydroponics, Rotorua NZ): establishment EC 0.8 mS/cm/pH 5.8, vegetative-growth EC 1.0 mS/cm/pH 5.8, fruiting EC 2.2 mS/cm/pH 5.6 — real, staged, commercial hydroponic raspberry EC/pH data, though incidental to the paper's actual tested variable (substrate, not feed). Adds a further real data point alongside the already-logged Klaros/HydroBuddy/PSI-Berryplants conflicts against Raspberry's existing verified, outcome-tested Bazangeya et al. 2025 figures (1.2–1.7 mS/cm/pH 5.5–6.5) — broadly consistent in shape (EC rising toward fruiting) but not identical. Logged as a corroborating/conflicting citation; not applied — Raspberry's displayed NPK/EC/pH unchanged.

Real, species-exact (Rubus idaeus, matches this file's Raspberry row) — likely Treftz & Omaye, referenced elsewhere in this file as the source of Bazangeya et al. 2025's "Recipe A" comparison baseline (a flat 500 ppm regime using General Hydroponics FloraSeries). CORRECTED REASONING this session (per Fred): using a commercial product within academic research does not itself disqualify the source. This entry stays unusable for the plain reason already stated — it's given only as one undifferentiated "500 ppm" total figure, with no elemental N-P-K breakdown at all, regardless of which fertilizer produced it. Not applicable.