The potential for dry weather across the state this spring raises concerns about the impact of dry soils on preemergence herbicides.
Preemergence herbicides kill weeds by being absorbed into the seed as the seed imbibes water. To be effective, the herbicide must be located within the soil profile at the depth where weed seeds germinate (primarily the upper 1 inch of soil). In addition, there must be sufficient water to keep the herbicide dissolved in soil water.
It typically takes at least one-half inch of rain to activate the...