# 7 steps for easy sprayer calibration

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Applying chemicals with a sprayer that is not calibrated correctly can be waste of chemicals and money, according to Ohio State Extension Spray Technology Specialist Erdal Ozkan. He offers these tips to getting your sprayer ready for the spring season.

### Nozzles

Before starting calibration, make sure you have a good set of nozzles on the sprayer. Nozzles can wear through extended use and can get clogged.

Clean and check the output of nozzles for a given length of time and compare the output from each nozzle. Replace nozzles showing output errors of more than 10 percent. Once nozzles are checked, it’s time to calibrate.

### Calibration steps

1. Fill the sprayer at least half full with water and run the sprayer to inspect for leaks and to make sure the sprayer is functioning properly.
2. Measure the distance in inches between the nozzles and measure an appropriate travel distance in the field based on this nozzle spacing. The appropriate distances for different nozzle spacing is as follows: 408 feet for a 10-inch spacing, 272 feet for a 15-inch spacing, 204 feet for 20-inch spacing, 136 feet for a 30-inch spacing, and 102 feet for a 40-inch spacing.
3. Drive through the measured distance in the field at normal spraying speed and record the travel time. Repeat this step at least two to three times and average the measurements.
4. With the sprayer parked, run the sprayer at the same pressure level and for the same amount of time it took to travel the marked distance from the last step, and catch the output from the nozzles.
5. Calculate the average nozzle output by adding the individual outputs and then dividing by the number of nozzles tested. The final average nozzle output in ounces is equal to the application rate in gallons per acre. For example, if you catch 15 ounces from a set of nozzles, the actual application rate of the sprayer is equal to 15 gallons per acre.
6. Compare the actual rate with the recommended or intended rate. If the actual rate is more than 5 percent higher or lower than the recommended or intended rate, make adjustments in the spray pressure, the travel speed or both. For example, to increase flow rate either slow down or increase spray pressure (the opposite is true to reduce application rate).
7. Repeat steps 3-6 until the recommended application error of 5 percent is achieved.

Sources: The Ohio State University Extension.

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