11 Ways to Avoid Sprayer Tank Sludge

Sprayer nozzles ( Sonja Begemann )

Farmers wear many hats: business owner, chemist, agronomist, machinery operator, and the list goes on. When it comes to the chemist hat, it can be challenging to make sure you get certain insecticide, herbicide or fungicide mixes just right to avoid a soupy, sludgy mess.

Fortunately, there is an 11-step program you can follow to avoid “cottage cheese” in your sprayer lines, according to Sara Smelser, agronomist at Green Point Ag.

“I would say 85% of the calls I’ve received about tank mixing issues could have been prevented,” Smelser adds.

Before you get started mixing ingredients, here are a few general reminders. First, fill your tanks half full of water before adding any active ingredients.

“Dilution is the solution to pollution,” Smelser reminds farmers. It’s a great way to prevent clogged up tanks, booms, inductor cones and nozzles.

Allow plenty of time between ingredients—dumping a high level of concentrates can lead to a big mess. Also, remember the acronyms WALES and DALES.

W-wettable powders (or D-Dry flowables)



E-EC formulations


Now, it’s time to get started. Mixing order matters, and Smelser recommends the following:

  1. Water
  2. Defoamers or antifoamers
  3. Water conditioners (have water tested if you’re unsure of the hardness)
  4. Drift reduction agents (this is an exception to the WALES and DALES rule as it is a surfactant, but it times time to activate and provides better performance when added after water conditioner)
  5. Ws or Ds of WALES and DALES (wettable powders and dry flowables)
  6. Agitate the mix
  7. Liquid flowables and suspensions
  8. Emulsified concentrates
  9. Glyphosate—if included in the mix, as it is the last pesticide product to go in the tank
  10. Surfactants/adjuvants
  11. Top off with water

It’s often a good idea to test the mix before placing it into a spray tank. Consider a jar test that could save time, money and a headache later, Smelser adds.