What is a stock solution in fertigation?

A stock solution is a concentrated fertilizer solution mixed in a tank. An injector (Venturi or pump) dilutes it into the irrigation water at a fixed ratio, typically 1:100 to 1:200, delivering a much weaker working solution to the plants.

What injection ratio should I use?

A 1:100 ratio (1 L stock per 100 L water) is the most common for Venturi injectors. Dosatron units often run 1:100 to 1:200. Higher ratios (more dilute stock) reduce the risk of salt burn if the injector sticks open. Check your injector manufacturer specifications.

How do I handle multi-nutrient fertilizers?

Enter the combined nutrient percentages from the fertilizer label. If you blend two products, calculate each separately and add the resulting fertilizer masses together before mixing the stock tank.

Why does the stock concentration depend on flow rate?

The injector must deliver enough concentrated solution per hour to meet the nutrient dose over the irrigation event. Higher flow rates require either a faster injector or a more concentrated stock to deliver the same kg/ha of nutrient.

What units does this calculator use?

Field area in hectares, flow rate in liters per hour, nutrient rates in kg per hectare, fertilizer analysis as weight percent, and output concentrations in grams per liter (g/L). Convert acres to hectares by multiplying by 0.4047.

Can I use this for soluble powder fertilizers?

Yes. Soluble powders and liquid fertilizers both dissolve into the stock tank. Enter the declared analysis (% N-P-K) from the label. For liquids, convert the liquid density and declared g/L content to weight percent first.

Drip Fertigation Calculator

Name: Drip Fertigation Calculator
Availability: InStock
Author: Nham Vu

Calculate stock solution concentration and injection rates for drip fertigation systems based on your field area, crop nutrient requirements, and irrigation flow.

System Parameters

Field Area (ha)

Irrigation Flow Rate (L/hr)

Irrigation Duration (hr)

Injection Ratio (1 : X)

1 part stock solution per X parts irrigation water

Nutrient Rates & Fertilizer Analysis

Nutrient Rate (kg/ha) Analysis (%)

P₂O₅

K₂O

Fill in the parameters and click Calculate to see your fertigation plan.

Injector Settings

Total Water Volume

—

liters / event

Stock Volume Injected

—

liters / event

Injector Pump Rate

—

L/hr

Injection Ratio

—

stock : water

Fertilizer Breakdown per Irrigation Event

Nutrient	Total Fertilizer (g)	Stock Conc. (g/L)	Working Conc. (mg/L)

Stock concentration = fertilizer mass needed / stock volume injected.
Working concentration = nutrient mass / total water volume.

Stock Tank Mixing Guide

Summary

Calculate stock solution concentration and injection rates for drip fertigation systems based on your field area, crop nutrient requirements, and irrigation flow.

How it works

Enter your total irrigated field area and the irrigation system flow rate.
Set the desired nutrient application rate (kg/ha) for N, P2O5, and K2O.
Enter the fertilizer analysis (% N, % P2O5, % K2O) from the product label.
Set your injection ratio (e.g. 1:100 means 1 part stock to 100 parts water).
The calculator returns the stock solution concentration (g/L) and injector pump rate (L/hr).
Review the total fertilizer mass needed per irrigation event for ordering or mixing.

Use cases

Design fertigation programs for greenhouse vegetable production.
Calculate fertilizer quantities for drip-irrigated orchards and vineyards.
Set injector pump rates for automated fertigation controllers.
Compare cost and nutrient delivery of different fertilizer formulations.
Convert field nutrient requirements into stock tank mixing instructions.
Verify existing fertigation settings before a new season.
Scale up fertigation from trial plots to full commercial fields.
Train agronomists and farm technicians on fertigation calculations.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu