Tank Mixing Pesticides: WALES Method
Prior to mixing any chemicals it is recommended to perform a small scale trial either by mixing the chemicals together in a small jar or within a pail to ensure that the products are compatible. It is also recommended that prior to mixing applications of any spray materials, the sprayer be thoroughly cleaned to ensure that residues from previous applications are not remaining in the spray tank.
By following these procedures, compatible products can generally be mixed within the spray tank without incidence.
The WALES method of tank mixing chemicals:
- Fill the spray tank until it is approximately half full
- Pre-dissolve and mix wettable powders, water dispersible granules, water soluble packages, and other powdered materials. Use a separate pail for each product
- With the agitator operating, first add pre-dissolved water soluble packages, then with the filling hose, rinse any remaining powder through the filling screen, rinse the pail, and add rinsate into the sprayer
- With the agitator still in operation, repeat step 3 with all the other pre-dissolved powder products
- Measure and add liquid products (not the emulsified concentrates) into the spray solution
- Measure and add emulsified concentrates into the spray solution
- Fill the spray tank close to the final desired volume
- If required, add any necessary surfactants into the solution