Everything in Order: Tips for mixing herbicides in the right order

To be sure you are getting the most effective results from your herbicide investment requires paying close attention to the order you add products to your spray tank. A good rule of thumb is using the WAMLEGS method as follows: 

1. Wettable powders, dispersible granules, soluble granules 

2. Agitate tank-mix thoroughly 

3. Micro-encapsulated suspensions  

4. Liquid flowables and suspensions   

5. Emulsifiable concentrate formulations  

6. Glyphosate formulations  

7. Surfactants  

Here’s a helpful reminder on the steps to follow when filling the spray tank: 

1. Start with a clean empty sprayer. Ensure sprayer is equipped with 50 mesh screens or filters. 

2. Fill sprayer tank half-full of clean water 

3. With agitator running, add the FMC products according to their formulation as shown in the WAMLEGS chart.  Add the products slowly. Ensure agitation reaches all parts of the tank.  

4. If using a mix and fill tank, add the FMC product to as large a volume of water as possible in a chemical handler.  

5. Add product to tank and agitate for 10 minutes.  

6. Proceed with adding additional products as per the WAMLEGS chart and water while maintaining agitation. Ensure each product is agitated sufficiently before proceeding to the next tank-mix partner.  

7. For repeat tank loads, start off with an empty tank or ensure spray solution is reduced to 10% or less of the original volume.  

8. Recommended:  For the last load of the day, add 10 L of household ammonia (containing at least 3% ammonia) to the tank heel PRIOR to the addition of the FMC product, water and glyphosate.  Follow steps 2 through 6. 

9. Recommended: When spraying an FMC product for multiple days in a row, it is important at the end of each day to fill the sprayer with water overnight to prevent any film from developing on the tank walls.