The extremely dry spring may reduce the effectiveness of preemergence herbicides. The products must be watered-in or rained-in to move them below the canopy and down to the soil where they will be effective. Herbicides not watered-in may also photodegrade faster than those wateredin. Early research showed a 44% loss in three days of preemergence herbicides through photodegradation when applied to bare soil and not watered in (like the thin areas next to walks and drives). In a turf setting, 10% loss was within 7 days when not watered into the turf. Granular products likely will not be as susceptible to photodegradation as the sprayable herbicides. Unfortunately, there’s not much we can do now other keep a careful eye on these lawns for early breakthrough.