How to Mix Herbicides


For bulk application, such as use on yards or in large gardens, herbicides are often sold in concentrated form. Before you can use a concentrated herbicide, you must mix it with water. Herbicides that are sold as tank mix combine two or more herbicides, or combine an herbicide and fungicide, that can be mixed in the tank of a tank sprayer. Tank mixes are designed to work synergistically to combat a range of problems.

Step 1

Read all literature that is included with your herbicide to become familiar with warnings and safety precautions. Herbicide poisons that will kill plants are also harmful to humans. Mixing instructions will vary among herbicide brands. The directions will indicate how much water to add to herbicides.

Step 2

Wear protective clothing when handling and mixing herbicides, including rubber boots, a plastic apron, long sleeves, long pants, plastic gloves, breathing protection and safety goggles. Your skin might absorb the herbicides, so take a shower immediately after mixing or using them. If the herbicide splashes onto your skin, wash it off immediately.

Step 3

Test the pH of your water before mixing it with herbicides using a swimming pool pH testing kit. Hard water with high pH might reduce the effectiveness of herbicides and cause incompatibility in tank mixes. Use water that is a neutral pH between 6.5 and 7.5 to mix your herbicide.

Step 4

Measure out the correct amount of all component chemicals and water into measuring buckets with measurements marked on the side of the container. Or pour the component chemicals and water into a holding tank marked with measurements on the side. Always pour the chemicals and water in the order listed on the instructions that are included with the herbicide component chemicals.

Step 5

Stir the herbicide mix with a stirring rod.

Tips and Warnings

  • Use herbicides immediately after mixing. Mixed herbicides that sit become less effective.

Things You'll Need

  • Herbicide concentrate
  • Rubber boots
  • Plastic apron
  • Long sleeves
  • Long pants
  • Plastic gloves
  • Breathing protection
  • Safety goggles
  • Water pH testing kit
  • Measuring buckets
  • Tank sprayer
  • Stirring rod


  • Grounds Maintenance: The Do's and Don'ts of Tank-Mixing Herbicides and Fertilizers
  • Iowa State University Extension: Manage Brush Effectively and Economically With Herbicides
  • Dow AgroSciences: Prestige Herbicide Tank-Mix

Who Can Help

  • Alabama Cooperative Extension System: Aquatic Weed Management
Keywords: mixing herbicides, weed chemical mixing, tank mixing herbicide

About this Author

Tracy S. Morris has been a freelance writer since 2000. She has published two novels and numerous online articles. Her work has appeared in national magazines and newspapers, including "Ferrets," "CatFancy," "Lexington Herald Leader" and "The Tulsa World."