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Mixing order: Make the most of your spray applications
You’ve evaluated your site, you’ve selected the right herbicide for the weeds or brush you’re targeting, and you’ve checked the weather for wind or inversions. Now, you have nothing to think about other than getting these acres sprayed and moving on to the next, right?
Not quite. There’s one more critical step in the process, one that could easily mean the difference between a successful application and a redo scenario: proper mixing, including selection of the right adjuvant. Use the wrong adjuvant, and your application won’t have near the intended effect. Get the mixing order wrong, and you could end up with a spray tank full of useless goo.
“Mixing order is critically important, because it directly relates to how well all the products in your tank mix go into solution. And what happens if they don’t go into solution? Well, first off, you could end up with a mess in your spray tank that takes a lot of time to clean up.”
—Jerome Otto, market development specialist, Corteva Agriscience
But proper mixing is about more than just avoiding a hot afternoon spent cleaning out a gummed-up tank. Add your chemistry in the wrong order, and you may be coming back in a few months to re-treat those acres. Or, worse yet, you may create “streaky,” or inconsistent, coverage that both looks bad and invites complaints from the public.
“When you don’t get the tank-mix products fully into solution,” Otto says, “you’re not getting the active ingredient applied at the rate that you want, and that can impact the performance of the products that you’re applying.”
An easy way to remember mixing order
Fortunately for busy applicators, there’s an easy way to remember the right order in which to add products.
“The individual product formulation is going to help the applicator understand in what order to add that specific product. So we always start off with the spray tank two-thirds full of water and then make sure we have constant agitation throughout the mixing process.”
After that? Simple. Just remember WALES:
Wettable powders, water-soluble packets and water-dispersible granules go in first, so they have plenty of time to dissolve completely.
Agitation, which should be continuous throughout the mixing process.
Liquids are added next, slowly and one at a time to ensure they go completely into solution. If your tank mix includes multiple types of liquids, then add suspension concentrates first followed by soluble liquids.
Emulsifiables are added next in the mixing order.
Surfactants or any other spray adjuvants come last.
And just because it comes last in the mixing order, don’t ignore the importance of proper adjuvant selection.
“Adjuvants are critically important to make sure the herbicide you’re applying does its intended job,” Otto says. “For example, let’s say it’s a little bit dry; you want to have an adjuvant that will help penetrate the waxy cuticle of the leaf. Having the correct adjuvant at the correct rate will make sure that the herbicide ends up going into the target plant and getting good control. Conversely, failure to use a correct adjuvant could result in reduced performance of that herbicide.”
Last, but perhaps most important, make sure you check those labels before mixing any products. That’s where you’ll find any special precautions regarding water pH, temperature or other factors that could affect the performance of your tank mix.
Looking for more detail? Need to know how to perform a jar check? Then make sure to read our in-depth guide to herbicide formulations and mixing.
Always read and follow label directions
Vistas®
For over 30 years, Vistas® has covered strategies, trends and stories from across the Vegetation Management industry.