Calibrating a stand-on sprayer before arriving on a customer’s property can save lawn care operators (LCOs) many headaches caused by over- or under-applying products. It’s recommended that professionals recalibrate sprayers each time they change the spray pressure.

To calibrate a sprayer, LCOs must find three measurements: distance, time and volume. The distance it takes for equipment to spray an area of 1,000 sq. ft. can be found by dividing the effective spray width of the nozzle, which should be specified by the manufacturer, by 1,000.

To find the time, contractors can mark that distance on a lawn with cones, flags or paint. Use a timer to record how long it takes the equipment to travel that distance. Next, use the time to find how much a machine can spray for that duration. With a second person operating the sprayer, use a PVC pipe joint or other equipment to direct the spray flow into a graduated cylinder or other tool to measure the volume of a liquid.

Using the measurements for distance, time and volume, calculate the amount of chemical per gallon to add to the tanks. To convert a measurement recorded in fluid ounces to gallons, divide the number by 128.

Follow these steps to properly calibrate a stand-on sprayer.

Step 1

Conduct a precalibration check by inspecting the machine’s filters and nozzles for clogs, cleaning tanks and setting the spray pressure to the manufacturer’s recommendations.

Step 2

Find the distance it takes for the sprayer to cover 1,000 sq. ft. by dividing the effective spray width of the equipment by 1,000.

Step 3

Time how long it takes to cover 1,000 sq. ft. Mark a course as long as the distance your sprayer must travel from Step 2 and time your sprayer driving this course three times. Take an average of those times for accuracy.

Step 4

Measure the output volume for the time it takes to cover 1,000 sq. ft. Have a second person operate the sprayer for the duration of the time found in Step 3, and use a graduated cylinder to measure the spray output for that time. Do this three times and average the results for accuracy.

Step 5

Use steps 2-4 to determine how much chemical to put in the tanks. To convert fluid ounces to gallons, divide by 128.

To download a PDF copy of this page from the magazine to use as a training tool at your company, click here.

Source: Turfco
illustrations: David Preiss