Spectracide Weed Stop For Lawns Plus Crabgrass Preventer Granules will control all of your lawn’s weeds in one application. This granular formula will kill over 200 lawn weeds commonly found in home lawns including dandelion chickweed thistle and clover and will prevent crabgrass and other undesirable annual grasses. It provides up to 5 months of control and it won’t harm lawns when used as directed. Recommended for established turf grasses including Kentucky bluegrass and more. In the spring the ideal time to apply is just before or while forsythia is in bloom or when the first dandelion flowers appear. In southern areas (see the map on the product label) make a second application in six to eight weeks for best weed and crabgrass control. In the fall apply Spectracide Weed Stop For Lawns Plus Crabgrass Preventer Granules when the weather cools and both grass and weeds are actively growing generally around Labor Day.