🌱 Nursery Fertiliser Calculator

Calculate elemental nutrient ppm in your irrigation feed
Install this app from your browser menu for offline use.

1. Fertiliser amounts

Enter the product amount added to a final 1,000 L concentrate. Amounts can be grams or kilograms per product.

FertiliserAmount addedUnit
Nutrient analyses are editable below. Verify against the exact product label.

2. Nutrient concentration in irrigation water

Estimated elemental nutrients after dosing. Assumes a 1,000 L concentrate batch.

Dose 1:100
Important: These are calculated additions from fertilisers only; they exclude nutrients already in your source water. This calculator does not check chemical compatibility or precipitation risk.

3. Nutrient totals

Elemental nutrient mass in the concentrate and final diluted-feed ppm.

NutrientAdded to 1,000 L (g)Concentrate (mg/L)Final feed (ppm)Final feed (%)

4. Add a new fertiliser

Create a custom product and enter its elemental nutrient percentages from the label. It will appear in the calculator above.

5. Fertiliser compatibility checker

Checks common concentrated-stock incompatibilities among products with a non-zero amount. This is a screening guide, not a guarantee.

Enter the amounts you intend to mix, then select Check current mix.

General caution: calcium-containing fertilisers can form precipitates with phosphate or sulphate sources in concentrated stock. Separate A/B tanks may be needed. Confirm with product labels, supplier guidance, water pH and a jar test.

6. Edit product nutrient analysis

Enter the percentage of each element (not oxide percentages) shown on the label. Missing values can be left at zero.

Use elemental P and K values. If a label reports P₂O₅ or K₂O, convert first: P = P₂O₅ × 0.4364; K = K₂O × 0.8301. For liquid products, this version assumes the entered amount is grams of product.

7. Save or export

Export the current mix, dose ratio, nutrient analysis and calculated results as a CSV file.

Mixes and custom products save on this device. Use Export full backup / Import backup to transfer your database between phones.

8. Feed level comparison

Compare your current calculated feed against indicative low, medium and high feed reference bands. These are evidence-informed starting references for general ornamental nursery fertigation, not universal ideal levels. Published guidance varies by crop and measurement method.

Live comparison
Important: Targets vary substantially by crop, growth stage, substrate, water alkalinity and fertiliser program. Feed targets below are editable planning references synthesized from container-nursery and greenhouse guidance. The low/medium/high tiers are practical comparison bands, not three levels directly tested in a single scientific trial. Confirm against crop response, EC, source-water analysis and tissue/media tests before changing feed strength.
NutrientCurrent ppmLow reference ppmMedium reference ppmHigh reference ppm

Current-feed ppm is the calculated concentration added by fertilisers and excludes source-water nutrients. Reference targets are elemental N, P, K, Ca, Mg, S, Fe and B in the final irrigation solution—not growing-media extract results. These are starting points for mixed ornamentals in coir/peat, and require crop-specific adjustment.

Edit irrigation-feed reference levels (ppm)

NutrientLowMediumHigh

Sources for feed-reference context: British Columbia Nursery Production Guide; Texas A&M AgriLife — Fertilizing Greenhouse Ornamental Crops. Reference tiers are editable starting points, not universal crop optima.

Calculation method: grams of product × elemental nutrient percentage ÷ 100 = grams of nutrient. With a 1,000 L concentrate, 1 g nutrient per 1,000 L equals 1 mg/L in concentrate. Final feed ppm = concentrate mg/L ÷ dose ratio. This assumes approximate water density of 1 kg/L and a 1 L concentrate dose per stated litres of water.