Proper Order for Mixing Chemicals and Required Safety Equipment​

Utilization of pesticide tank mixtures can be an efficient and cost-effective method for managing on-farm pests. However, improper mixing of chemical formulations can eliminate these benefits and may result in damaged equipment, delays in pest management and additional costs. Additionally, chemical and pesticide labels must be read prior to mixing materials to determine the compatibility of products. Mixing materials in a small container at the intended application rates should be used to determine compatibility. Although products may be compatible, improper mixing order of materials with different formulations can result in adverse interactions, adding to management costs and delayed applications. The proper mixing order of pesticides generally suggested by formulators are:1

  • Dispersible granules
  • Oil dispersion
  • Flowables
  • Emulsifiable concentrates
  • Solutions

Always start with 50% to 70% of the tank filled with water and start agitation. Add water conditioners before adding pesticides. Adjuvants should be added once the pesticides are in the tank and then fill the tank with water. Before handling any pesticide, always read and follow label directions carefully, including application rates, precautions and restrictions of each product used in the tank mixture. Inspect equipment and repair deficiencies prior to mixing pesticides. Tanks, booms and nozzles should be triple rinsed before adding new chemistries to the tank. Always mix chemicals in a well-ventilated area. Avoid skin contact when mixing, handling and applying chemicals. Review and follow all personal protective equipment (PPE) requirements on each product label. At a minimum, wear chemical-resistant gloves, a long-sleeved shirt, long pants, safety glasses and enclosed shoes.2 Neoprene or nitrile boots are recommended when handling pesticides to prevent exposure.3 Additional PPE must be worn when specified on the label. This may include chemical-resistant clothing, goggles and/or face shield, dust masks, or an approved respirator. Always follow the instructions for the pesticide with the most restrictive label to ensure the safety of individuals handling pesticides.



1Poindexter, S. 2013. Spray tank-mixing order important to minimize nozzle plugging. Michigan State University.

2​​Ogg, C.L., Bauer, E.C., Hygnstrom, J.R., Bright, F.J., Puckett, G.J., and Alberts, C.A. 2018. Protective clothing and equipment for pesticide applicators. NebGuide. G758. Nebraska Extension. University of Nebraska.

3Cyr, D.L. and Johnson, S.B. Personal protective equipment for pesticide handlers. Bulletin 2358. Maine Farm Safety Program. University of Maine Cooperative Extension.

Web sources verified 2/07/19.​

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