If you grow microgreens, lettuce, or herbs hydroponically, you will sooner or later face the same question: how much fertiliser do I add to the tank? Manufacturers say one thing, agronomists advise another, and the internet offers dozens of conflicting tables. The UAorganic NPK Calculator solves this once and for all.
What the NPK Calculator Is
It is a free web application (uaorganic.com/npk-calculator) that installs on your phone or computer as a PWA and works offline. No registration, no subscription — just open it, configure it once, and use it.
Section 1 — Calculator
The main screen. Select a crop (for example, Microgreens), choose the growth phase — Start or Vegetation — and enter your tank volume: from 1 to 1,000 litres. Use the slider or the quick buttons: 5 / 10 / 20 / 50 / 100 / 500 / 1000 L.
The calculator instantly shows dosages in millilitres for each component (A, B, C), adjusted for phase and volume. Alongside it displays the calculated EC level (electrical conductivity) — for example, ~0.64 mS/cm for microgreens at Start or ~1.29 mS/cm in the Vegetation phase. No manual formulas.
Section 2 — Recipe
This is where nutrient profiles are stored. The calculator includes two built-in profiles:
- Profile 1 — Greens and Microgreens: component A (Ferticare Hydro), B (Potanit + Maganit), C (Calcinit + Brexil Fe)
- Profile 2 — Fruiting Crops, Berries, Flowers: a different composition for more demanding crops
Each component lists the specific fertilisers and grams per concentrate. The addition order is always A → B → C. Calcium nitrate (component C) goes in last — this is a critical rule: violating it causes precipitation that clogs drip lines.
Section 3 — Seeding Norms
A database of seeding rates for 70 microgreen crops in an 11×19 cm tray. For each crop: seeding rate in grams, cycle length in days, approximate yield, and markers for whether soaking or weighting is required.
Search by name, filters, and “My Crops” stars — to show only the crops you grow. For example: Amaranth — 1–1.5 g / 13–17-day cycle / ~14 g yield. Broccoli — 2–3.5 g / 8–10-day cycle / ~30 g yield.
Section 4 — Diagnostics
A tool for identifying problems by symptoms. Yellowing leaves, edge necrosis, poor germination — describe what you see and get a likely cause with a recommendation. Useful when something goes wrong and you need a quick answer without an hour of searching.
Section 5 — My Profile
Personal settings. Enable the crops you grow — they appear first in the calculator and norms. Twelve crops available: Microgreens, Lettuce, Basil, Herbs, Mint, Chard, Tomato, Cucumber, Pepper, Aubergine, Strawberry, Flowers. Also here: a link to the Telegram support channel.
How to Mix a Nutrient Solution Correctly
The sequence is simple, but must not be broken:
- Fill the tank with water (e.g. 10 L)
- Add component A — Ferticare Hydro, stir for 30 seconds
- Add component B — first Potanit, then Maganit, stir
- Add component C — first Calcinit, then Brexil Fe — always last
- Check EC and pH. Target for microgreens at Start: EC ~0.6–0.8 mS/cm, pH 5.8–6.2
Never mix concentrates B and C directly — only add them separately into a large volume of water. Mixing them together creates calcium phosphate precipitate that will not redissolve.
Who It Is For
First of all, for anyone growing microgreens, basil, or lettuce hydroponically or on drip irrigation who wants precise dosing rather than guesswork. But it also works for beginners: no chemistry knowledge needed — just enter your crop and tank volume and get a ready recipe. Farmers with tanks from 100 to 1,000 litres will find it equally useful — dose scaling is automatic.
How to Install the App
The NPK Calculator runs as a PWA — it installs on your phone or computer without the App Store or Google Play, takes under 1 MB, and works offline. Full installation instructions for iOS, Android, and desktop:
uaorganic.com/npk-app → App description and installation guide
