What is the proper way to apply broadleaf herbicides to the lawn?

Broadleaf herbicides can be applied as liquids or granules.  Before applying any herbicide, carefully read and follow label directions.

Liquid Herbicides

When applying liquid formulations, potential spray drift problems can be avoided by following simple precautions.  Don’t spray when winds exceed 5 mph.  Also, don’t spray when temperatures are forecast to exceed 85 degrees Fahrenheit within 24 hours of the application.  Since coarse droplets are less likely to drift than fine sprays, select nozzles that produce coarse droplets and use low sprayer pressure when applying liquid broadleaf herbicides.  When spraying, keep the nozzle close to the ground.  If only a few areas in the lawn have broadleaf weed problems, spot treat these areas rather than spraying the entire lawn.  Apply just enough material to wet the leaf surfaces. 

Granular Herbicides

Granular broadleaf herbicides are often combined with fertilizers.  Apply granular broadleaf herbicides and fertilizer/broadleaf herbicide combinations when the weed foliage is wet.  Broadleaf herbicides are absorbed by the weed’s foliage, not its roots.  To be effective, the granules must stick to the weeds and the herbicide absorbed by the weed’s foliage.  Apply granular products in the early morning when the foliage is wet with dew or irrigate the lawn prior to the application. 

After Applying Any Herbicide

To insure adequate leaf surface and herbicide absorption, don’t mow the lawn 2 to 3 days before treatment.  After treatment, allow 3 or 4 days to pass before mowing.  This allows sufficient time for the broadleaf weeds to absorb the herbicide and translocate it to their roots.  To prevent the broadleaf herbicide from being washed off the plant’s foliage, apply these materials when no rain is forecast for 24 hours.  Also, don’t irrigate treated lawns within 24 hours of the application.