calibrating a boom sprayer

Calibrating a Boom Sprayer

March 2, 2017


Once you have your nozzles, a critically important step in efficiency and effectiveness in your chemical usage is calibrating your sprayer. Taken in steps it’s not nearly as bad as it may seem. Here’s one method.

Basing your calculations on the fact that one ounce equals 1/128th of a gallon, you can calculate each ounce to equal one gallon per acre. First, you’ll need to figure out the time it takes for one nozzle to cover 1/128th of an acre- which if your spacing is a typical 20”, that will be 204 feet. For other nozzle spacings download the calibration instructions PDF and see the chart at the bottom of page one. The chart also shows exactly how many seconds it will take to travel your distance at speeds between 3-7 mph. Ex.- it shows if you are traveling at 5 mph, it will take you 28 seconds to travel 204 feet.

Next collect the liquid from one nozzle, at the pressure you plan to spray at, for the same amount of time that it took to travel your distance. The number of ounces collected equals gallons per acre; if you collect 15 ounces in that time, you are spraying 15 gallons per acre.

The two ways to change your rate are to either adjust the pressure, or adjust your speed. If greater adjustments are needed select another nozzle.

Don’t rely on just one measurement- take several and then average them. Naturally, you can’t assume one nozzle will be equal to the rest. Clogged or worn nozzles with greatly change the rate so you’ll want to make sure each nozzle is operating optimally.

Download this calibration instructions pdf for more details on calibrating sprayers (especially recommended for mobile viewing.)

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