Use spectracide weed stop for lawns plus crabgrass killer concentrate (Ready-to-Spray) to kill over 250 types of weeds as listed, including crabgrass. The product produces visible results in 8 hrs. This product kills broadleaf and troublesome grass weeds including dandelion, chickweed and clover as well as crabgrass, foxtail and yellow nutsedge, see product label for complete list of weed types.