As is the case with all chemicals, one should carefully read the label and follow application instructions. Of special concern with this type of herbicide is the long lasting residual effect in the soil which may adversely affect newly seeded turfgrass. If seeding of turfgrass is planned following application, pay particular attention to the recommended interval on the label between application and seeding new turfgrass. For maximum effectiveness, the herbicide should be watered-in within two or three days of application. Consult the label for additional information.
Timing is everything when it comes to application of a preemergent herbicide.
While it is commonly assumed that blooming of forsythia signals the time to apply the herbicide, this assumption does not always ring true. Under normal conditions, in this part of Pennsylvania preemergent herbicides for control of crabgrass should be applied between March 15 and April 15. Snow mold is a fungal disease that attacks turfgrass. Signs of this disease are usually noticed in the spring as the snow melts and typically appear as off-color, crusted, matted leaves of turfgrass. Affected areas may range from several inches to several feet across.