# Crop: Hydroponic Calculator — Nutrient charts, EC & PPM > Hydroponic nutrient calculator with cited plant recipes and reservoir tracking. (iPhone/iPad app by Roman Kopaliani.) - Source: https://appshunter.io/ios/app/crop-hydroponic-calculator/id6777968635 (this page in markdown: same URL + `.md`) - Developer: [Roman Kopaliani](https://appshunter.io/developer/1635315269) - Category: Utilities, Lifestyle - Price: Free with in-app purchases - Rating: 5.00/5 from 2 App Store ratings · 1 written reviews indexed - Age rating: 4+ - Requires: iOS 17.0 · 1 MB - Languages: American English - Released: 2026-06-11 - Data updated: 2026-08-20 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/crop-hydroponic-calculator/id6777968635/reviews.md ## What is Crop? Crop is a hydroponic nutrient calculator for greenhouse vegetable growers, leafy-greens hobbyists, herb gardeners, and microgreen producers. Every plant + stage target cites a primary source — Cornell CEA, Penn State Extension, UF/IFAS, or Produce Grower — so you can verify the published recipe behind every number. WHAT'S INSIDE • Plant + stage targets — lettuce (seedling + mature head), tomato (seedling, vegetative, fruiting), basil, leafy herbs (cilantro, parsley, mint, chives), cucumber, pepper, strawberry (fruiting), leafy greens (kale, chard, spinach, arugula), and microgreens. Lettuce, tomato, and herbs are the fully cited core; the rest is surfaced as broad guidance with explicit "per-stage tables are thinner for this crop" framing. • Branded recipes — MasterBlend Tomato 4-18-38 (2:2:1 with calcium nitrate + Epsom), MasterBlend Lettuce 8-15-36 (the Cornell CEA leafy recipe), Jack's 3-2-1 (Jack's 5-12-26 + 15-0-0 calcium nitrate + Epsom), and the General Hydroponics Flora trio (Lite Feeding and Aggressive Leafy ratios). • Twenty cited salts — calcium nitrate tetrahydrate, KNO₃, KH₂PO₄, K₂SO₄, MgSO₄·7H₂O, ammonium nitrate, monoammonium phosphate, magnesium nitrate, iron EDTA and DTPA, MnSO₄, ZnSO₄, CuSO₄, boric acid, sodium borate, sodium molybdate, calcium chloride, potassium chloride. Every percentage is derived from the chemical formula using IUPAC 2021 atomic weights. • Target → salt-weight solver — the Resh / Mattson sequential satisfy textbook method. Enter your reservoir volume and a target ppm or pick a plant + stage, and Crop calculates the grams of each salt to mix. • Reverse calculation — enter the salt weights you actually used and see the delivered ppm per element. • Multi-reservoir EC + pH log — track a separate reservoir per crop or per zone, log readings over time, and surface drift warnings cited to the published source ("Per Cornell: lettuce mature 1.4–1.8 mS/cm; you logged 2.3 — dilute or top up plain water"). • Share-sheet mix sheet — export the day's reservoir target + salt weights + EC/pH range + named-source citation as plain text. Send it to yourself, paste it into your shop notebook, or print it. • Unit flexibility — US gallons or liters, grams or ounces, EC scale 500 / 640 / 700 (matches Hanna, Bluelab, Cornell tables, or European meters). DISCLAIMER Crop presents Cornell CEA, Penn State Extension, UF/IFAS, and Produce Grower guidance for educational purposes. Verify recipes against current publications and your own meter readings before mixing at scale. CITATIONS Plant + stage recipes are sourced from Cornell CEA (Mattson & Lieth), Penn State Extension, UF/IFAS, and Produce Grower. Branded product analyses come from the manufacturer's published guaranteed-analysis labels and feeding charts. Method references are Resh, Hydroponic Food Production (7th edition), and Mattson & Lieth's hydroponic recipe calculation notes. Salt elemental percentages are derived from IUPAC 2021 atomic weights and CRC Handbook (100th edition) formula masses. NO ACCOUNT. NO ADS. NO TRACKING. NO SUBSCRIPTIONS. Crop does not collect any personal data. Everything stays on your device. One-time purchase, lifetime updates. ## Key features - Plant and stage-specific nutrient targets - Cited primary source recipes - Branded nutrient solution recipes - Target to salt-weight solver - Reverse calculation for used salts - Multi-reservoir EC/pH logging - Shareable mix sheets ## Pricing and in-app purchases Base price: Free. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Crop Pro (lifetime) | $4.99 | one-time | ## Recent user reviews (1 of 1) All indexed reviews: https://appshunter.io/ios/app/crop-hydroponic-calculator/id6777968635/reviews.md ### 5/5 — Actually get my ppm right now *2026-07-01* used to keep a messy spreadsheet for my res and still mess it up half the time. this does it in like 10 seconds. wish i found it before i cooked a whole batch of lettuce lol ## Frequently asked questions about Crop ### What plants does Crop support? Crop supports a variety of plants including lettuce, tomato, basil, leafy herbs, cucumber, pepper, strawberry, leafy greens, and microgreens. Specific recipes are fully cited for lettuce, tomato, and herbs, with broader guidance for others. ### Where do Crop's recipes come from? Recipes in Crop are sourced from primary research institutions like Cornell CEA, Penn State Extension, and UF/IFAS, as well as Produce Grower. This ensures the published recipes behind the calculations are verifiable. ### How does Crop calculate nutrient amounts? Crop uses the Resh / Mattson sequential satisfy textbook method. You can enter your reservoir volume and a target ppm, or select a plant and stage, and Crop will calculate the exact grams of each salt to mix. ### Can Crop help me track my reservoir's condition? Yes, Crop offers multi-reservoir EC + pH logging. You can track separate reservoirs, log readings over time, and receive drift warnings cited to published sources. ### What units does Crop support? Crop provides unit flexibility for US gallons or liters, grams or ounces, and EC scales of 500, 640, or 700 to match common meters and tables. ### Is Crop suitable for beginners? While Crop provides detailed, cited information, its focus on scientific sources and precise calculations makes it most valuable for experienced growers. Beginners may find the depth of information requires some prior knowledge. ### How often is Crop updated? The latest version, 1.2, was released on July 2, 2026, indicating active development. Users can expect updates to maintain accuracy and potentially add new features or plant data. ### Does Crop have ads? No, Crop does not contain advertisements. It is a free application focused on providing utility without intrusive ads. ## Version history (last 5 releases) ### 1.6 — 2026-08-15 Maintenance update. No feature changes. ### 1.5 — 2026-07-25 • Fixed Restore Purchases so returning customers reliably get their unlock back • The free trial now shows how much time is left ### 1.4 — 2026-07-23 Behind-the-scenes improvements for a smoother, faster app. ### 1.3 — 2026-07-16 The number keyboard now has a Done button, so you can dismiss it when you're finished. Thanks to everyone who wrote in about this. ### 1.2 — 2026-07-02 New: a quick-jump list of related Moon Dog grower's calculators in Settings — planted tanks, lawns, mushrooms and off-grid water. Plus reliability improvements. Happy growing. ## More apps by Roman Kopaliani - [Soak: Hot Tub & Spa Calc](https://appshunter.io/ios/app/soak-hot-tub-and-spa-calc/id6775030424) - [Frost: Cold Plunge Care](https://appshunter.io/ios/app/frost-cold-plunge-care/id6776702484) - [Reef: Aquarium Chemistry Calc](https://appshunter.io/ios/app/reef-aquarium-chemistry-calc/id6776750986) - [Pond: Koi Chemistry](https://appshunter.io/ios/app/pond-koi-chemistry/id6777459595) - [Watt: Solar for Van & RV](https://appshunter.io/ios/app/watt-solar-for-van-and-rv/id6777471058) - [Saline: Saltwater Pool Calc](https://appshunter.io/ios/app/saline-saltwater-pool-calc/id6777715538) All apps by Roman Kopaliani: https://appshunter.io/developer/1635315269 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-20.*