Cleaning Herbicides from Sprayers

Chris Boerboom, Extension Weed Scientist

The proper procedure to clean a sprayer after using a herbicide is specified in detail on many herbicide labels and should be followed to avoid problems. On some labels, the cleaning procedures will recommend that the cleaning solution stand in the sprayer for several hours to overnight. Cleaning a spray tank is not a job that should be rushed, especially with certain herbicides that are highly active on sensitive crops such as with dicamba-based products and soybeans or glyphosate on non glyphosate-resistant corn. The cleaning agents that are recommended on the herbicide labels in the table below are summarized as a reminder to check the label for cleaning instructions. The exact steps to clean spray tanks as described on the labels are not summarized or simplified here because the specific details differ among labels.

1. Flush the sprayer tank, lines, and booms thoroughly with clean water and apply the pesticide‑contaminated rinsate to labeled sites.
2. Fill the sprayer to capacity with water, adding 1 cup of trisodium phosphate or household ammonia for each 10 gallons of water. If neither is available, use a strong detergent or soap. Hormone‑type herbicides (e.g., 2,4‑D, dicamba) are best removed with ammonia.
3. Wash the tank and pump parts thoroughly by running the sprayer for about 5 minutes with the flow to the nozzles turned off.
4. If possible, let the cleaning solution stand in the sprayer overnight. (Please note: household ammonia will corrode aluminum sprayer parts.)
5. Discharge the liquid from the tank, spraying some through the nozzles.
6. Drain the sprayer completely and remove nozzles, screens, and strainers.
7. Scrub all accessible parts with a stiff bristle brush.
8. Rinse the sprayer thoroughly with clean water and reassemble.

See Table 1 for Cleaning Agent recommended on label >>>>   table1cleanting.pdf