Guide

How to calibrate a sprayer

A jug, a stopwatch and a measured pass give the gallons per acre your sprayer really applies.

Three measurements

Nozzle flow: hold a jug under one nozzle at working pressure for a set time.
Forward speed: time the sprayer over a marked course, or measure it with GPS.
Nozzle spacing on the boom.

The formula

Gallons per acre = 5,940 × gallons per minute per nozzle ÷ (mph × nozzle spacing in inches).

Example

32 fl oz caught in 30 seconds is 0.5 gallon per minute. At 5 mph with nozzles every 20 in: 5,940 × 0.5 ÷ (5 × 20) = 29.7 gallons per acre.

With Seed Calc

Calibrate the sprayer runs the catch test and the speed by GPS or stopwatch, and gives the volume applied or the nozzle flow you need. See Sprayer calibration.

Other guides

NPK to urea, DAP, MOP

A soil test gives pounds of N, P and K. The dealer sells bags of products. Here is the bridge.

Seed rate per acre

Plants per acre from the spacing, seeds from the germination, pounds from the grain weight.

Spray tanks

The total of liquid, the full tanks, and the last tank, where most mistakes happen.

Measure field area

Every quantity follows from the area. Here are the ways to get it, and how far to trust each.

Know what to buy before the season

Measure the field, enter your doses, send the list. No subscription.