Calibrate your backpack sprayer before broadcast applications
When using a backpack sprayer for an application where a fixed broadcast rate per acre is to be applied, it’s important to take the time to properly calibrate the sprayer to ensure effective results. It’s a simple but necessary process. Before beginning, remember 1 gallon is equal to 128 fluid ounces. Therefore, the calibration spray area should be sized to 1/128 of an acre. This will ensure the fluid ounces collected during calibration equates to gallons per acre.
First, make sure the sprayer and nozzle are clean and fill the tank with clean water. Spray some water on a surface to ensure the nozzle is working properly. Select a spray tip that provides a uniform pattern for the area you are treating. Then measure an area 18 ½ by 18 ½ feet, or 1/128 of an acre, in a field where the spray will be applied. Time the number of seconds it takes to spray the measured area uniformly by using a gentle side-to-side sweeping motion with the spray wand. Repeat this step and average the two times.
Maintaining a constant sprayer pressure, spray into a container for the average time just calculated. Then measure the number of fluid ounces in the container. This number is in fluid ounces and is equivalent to the number of gallons per acre the sprayer is delivering. For example, if 3 fluid ounces of water is collected in the container, the sprayer will deliver herbicide solution at a rate of 3 gallons per acre.
Following these simple steps to select and maintain a backpack sprayer will ensure more consistent and effective results when applying herbicides. More information on backpack sprayers and individual plant treatments, including how-to videos, can be found here.