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Note: All calibration needs to be done with water only!
When spraying with the boom, the sprayer must be calibrated to ensure proper spray coverage. Before calibrating the sprayer, it is
important to familiarize yourself with the operating instructions. The calibration process is simplied when broken down into the
following steps:
1. Calculate the speed of the sprayer or equipment.
2. Determine the nozzle size and consult the calibration chart for the desired or instructed Gallons per Acre (GPA).
Calibrating the Sprayer
1. Calculating the Speed
It is important to determine what speed you will be traveling at while spraying. While some tractors may have speedometers, it is still
recommended that speed always be calculated for accuracy purposes. To determine the speed follow these four steps:
1. Measure a 200 foot or 300 foot distance on a eld or a
surface similar to where you will be spraying.
2. Drive the equipment and sprayer (half-full is optimal)
across the measured distance at a constant rate of speed.
There should be no changes in speed while you are
measuring the time. This should be a comfortable speed
for spraying.
3. Have someone measure the amount of time (in seconds)
it takes to travel the measured distance.
4. Your speed can be calculated by entering your data into
the equation Speed (mph) = (Distance (ft) x 60) ÷ (Time
(seconds) x 88). You can also refer to the speed chart
(Figure 5) to the right.
2. Determining Nozzle Size
The spray nozzles on your sprayer are color-coded to match up with the calibration chart. After you have determined your nozzle
size, you need to look at the calibration chart. Using your calculated speed, nozzle size, and desired gallons per acre (GPA), nd the
pressure (psi) necessary to achieve your GPA. It is important to note that lower pressure settings will result in less spray drift.
Example: Assume you have found your calculated speed to be 6 MPH, your spray height is set at 24”, and you want to spray at 7
GPA. Upon looking at the chart, you nd that you should set the sprayer's pressure at about 23 psi in order to apply 7 GPA.
Note: It is helpful for future references to record the
exact RPM and gear used to nd your speed.
Speed in MPH
Time required (seconds) to travel a
distance of:
200 feet 300 feet
1.0 136 205
1.5 91 136
2.0 68 102
2.5 55 82
3.0 45 68
3.5 39 58
4.0 34 51
4.5 30 45
5.0 27 41
5.5 25 37
6.0 23 34
6.5 21 31
7.0 19 29
Figure 5
