Build an Advanced Nutrient Feed Recipe
Use crop targets, source water offsets, and injection settings to size fertilizer masses and stock solution strength.
Example Data Table
| Scenario | Batch Volume L | Injector | Target N-P-K | Target Ca-Mg-S | Source Ca-Mg-S |
|---|---|---|---|---|---|
| Tomato greenhouse | 1000 | 1:100 | 180-50-300 ppm | 170-50-65 ppm | 35-10-12 ppm |
| Lettuce NFT line | 600 | 1:75 | 140-35-220 ppm | 120-35-50 ppm | 18-6-8 ppm |
| Cucumber slab irrigation | 1500 | 1:120 | 190-45-280 ppm | 160-45-60 ppm | 28-9-10 ppm |
Formula Used
Base fertilizer sizing: Fertilizer mass in grams = (net nutrient ppm × final feed volume in liters) ÷ (fertilizer nutrient fraction × 1000 × efficiency).
Net nutrient ppm: Net ppm = max(0, target ppm − source water ppm). This prevents double counting nutrients already present in the makeup water.
Coupled salt balancing: Calcium nitrate covers calcium first, magnesium sulfate covers magnesium, and monopotassium phosphate covers phosphorus. Potassium nitrate, potassium sulfate, and urea then close remaining potassium and nitrogen gaps.
Stock concentration: Required stock g/L = fertilizer mass ÷ stock liters consumed, where stock liters consumed = final batch volume ÷ injector ratio.
Diagnostic sulfur: Sulfur is reported after balancing because sulfate salts also change potassium or magnesium. Large sulfur deviation means the recipe may need another compatible sulfur source.
How to Use This Calculator
- Select a crop profile or keep the fields custom.
- Enter final feed batch volume, stock tank size, injector ratio, and expected mixing efficiency.
- Enter target nutrient concentrations in ppm for N, P, K, Ca, Mg, and S.
- Enter source water nutrient values and the baseline EC reading.
- Submit the form to view the result block above the calculator.
- Review element balance, fertilizer masses, stock concentrations, and Tank A/B separation notes.
- Export the displayed recipe as CSV or PDF for operations, QA, or field records.
Frequently Asked Questions
1. What does this nutrient feed calculator estimate?
It estimates fertilizer masses, stock-solution concentrations, element delivery, sulfur deviation, and injector demand for a diluted feed recipe using common fertigation salts.
2. Why does source water matter?
Source water may already contain calcium, magnesium, sulfur, potassium, or nitrate. Ignoring those values can oversupply nutrients and raise EC unnecessarily.
3. Why are there Tank A and Tank B recommendations?
Calcium concentrates can react with sulfate or phosphate concentrates and form precipitates. Splitting incompatible salts improves stability and keeps injectors cleaner.
4. Why might sulfur miss the exact target?
Sulfur often arrives through magnesium sulfate or potassium sulfate. Those same salts also change magnesium or potassium, so sulfur becomes a constrained diagnostic value.
5. What does mixing efficiency change?
Efficiency adds a practical allowance for imperfect dissolution, transfer losses, or field handling. Lower efficiency increases required fertilizer mass.
6. Is the estimated EC an exact laboratory value?
No. It is a planning estimate derived from delivered major nutrients and source EC. Always confirm final EC with a calibrated instrument after mixing.
7. Can I use custom crop targets?
Yes. Choose the custom profile or edit any target field directly. The calculator uses the entered values during the next submission.
8. When should I export the result?
Export after reviewing deviations, stock demand, and tank compatibility. The CSV and PDF downloads help maintain repeatable operating records.