Fertigation Injection Rate Calculator

Injector ratio and PPM from stock solution and flow.

Target nutrient (ppm)

Injection ratio (1:X)

System flow (GPM)

Product nutrient (%)

Product density (lbs/gal)

Irrigation run time (min)

Tab to move between fields

Stock concentration (ppm)

20,000

Injection rate (GPH)

Injection rate (mL/min)1,892.7

Product (oz/gal stock)1.34

Total water applied (gal)3,000

Total nutrient (lbs)5

Stock solution needed (gal)30

Total product used (oz)40.1

Total product used (lbs)2.5

Recommended tank size (gal)33

Oz Per (gal) Stock10

How to Use This Calculator

Enter Target Nutrient (ppm) — the desired concentration in irrigation water (e.g., 200 ppm N).
Set Injection Ratio (1:X) to match your injector model (common ratios: 100, 128, 200).
Enter System Flow (GPM) and Irrigation Run Time (min).
Set Product Nutrient (%) and Product Density (lbs/gal) from the fertilizer label.
Read Injection Rate (GPH and mL/min), Stock Concentration (ppm), and Total Product Used (lbs) to configure your injector.

How the result changes with Target nutrient (ppm)

Target nutrient (ppm): Desired parts per million of nutrient in the irrigation water.
Injection ratio (1:X): Injector dilution ratio. Common: 100, 128, or 200.
System flow (GPM): Total irrigation system flow rate in gallons per minute.
Product nutrient (%): Nutrient analysis of the fertilizer product (e.g., 20% N).
Product density (lbs/gal): Weight of fertilizer product per gallon (liquid).
Irrigation run time (min): Duration of the irrigation cycle in minutes.

Stock concentration (ppm): Required concentration of the stock solution.
Injection rate (GPH): Gallons per hour the injector must deliver.
Injection rate (mL/min): Milliliters per minute for small injectors.
Product (oz/gal stock): Ounces of fertilizer product per gallon of stock solution.
Total water applied (gal): Total irrigation water for the run.
Total nutrient (lbs): Total pounds of nutrient delivered during the run.
Stock solution needed (gal): Gallons of stock solution consumed.
Total product used (oz): Ounces of fertilizer product consumed.
Total product used (lbs): Pounds of fertilizer product consumed.
Recommended tank size (gal): Minimum stock tank size with 10% buffer.

Identify Input Parameters
4 parameters
Target nutrient (ppm) = 200, Injection ratio (1:X) = 100, System flow (GPM) = 50, Product nutrient (%) = 20 = 6 input(s) provided
Calculate Stock concentration
Stock concentration = targetPPM * injectionRatio
20000 = 20000
Calculate Injection rate
Injection rate = (systemFlowGPM * 60) / injectionRatio
30 = 30
Calculate Injection rate
Injection rate = (systemFlowGPM * 3785.41) / injectionRatio
1892.7 = 1892.7