Agronomy blog · February 4, 2025
How to Choose a Spray Adjuvant for Your Herbicide Program
A step-by-step way to pick spray adjuvants that match herbicide labels, water quality, and your Midwest weed spectrum.
Start with the herbicide label, not the adjuvant aisle
Choosing a spray adjuvant begins with what the herbicide allows or requires—NIS, COC, MSO, AMS, drift reduction, or none. Skipping that step is how tanks get overloaded and performance gets blamed on the wrong jug.
Group your program by pass: burndown, pre-emerge, post-emerge grass, post-emerge broadleaf. Each pass may need a different adjuvant strategy.
Factor in water, weather, and weed size
Hard water, high pH, and dirty water change herbicide behavior. Hot, dry weather and large weeds often push growers toward oil-based adjuvants where labels allow them. Small weeds and sensitive crops may favor lighter NIS systems.
Drift-prone days call for adjuvants and nozzles that keep the pattern legal and effective. Do not use drift reduction as an excuse to ignore label wind and buffer rules.
Keep the mix simple enough to repeat
The best adjuvant program is one your crew can mix the same way every load. Write the order of addition on the nurse trailer. Jar-test new combinations. Track which fields needed a second trip.
Browse adjuvant options with Roush Ag Solutions or request a quote for the products that fit your herbicide labels this season.
Always verify rates, crops, tank-mix partners, and restrictions on the product label and SDS before you spray. This article is educational guidance for Midwest farmers—not a substitute for label directions or local agronomic advice.