Contact Information
971 Coffman Road, Building B
Whitewater, CO 81527

Mailing Address
Department 5087
P.O. Box 20,000
Grand Junction, CO 81502-5001

(970) 255-7121

Stationary Calibration Method for Boom Sprayers

  1. Fill the spray tank approximately ½ full with clean water. If a drift control agent will be used during the application, calibrate with drift control agent.
  2. Measure the swath width (SW) in inches.
  3. Collect the spray output from the nozzle(s) for 1 minute. Measure the volume collected in fluid ounces and divide by 128 to determine gallons per minute (GPM).
  4. Select the speed, in miles per hour, that will be used for spraying.
  5. Determine the gallons per acre (GPA) being applied, using a large output nozzle or a cluster of nozzles.
GPA = 5940 x GPM 
mph x SW (in inches)

GPA = GPM x 495 
mph x SW (in feet)
Chemical needed =

chemical rate x tank volume (in gallons)