Apply anytime between April 1st and approximately May 15th. For best result, apply before soil temperature reaches 60 degrees at a depth of 2 inches or before forsythia bushes have lost their blossoms, as this is a good indicator to soil temperature. It will prevent crabgrass, foxtail, goose grass, barnyard grass and a host of other annual weeds and weed grasses. It will control crabgrass for up to 3-4 months depending on application rate and soil conditions. Turf Line’s Crabgrass Preventer plus Fertilizer is fortified with all essential nutrients. It will promote stronger turf and quickly restore that deep rich green color. Use only on established lawns. Do not apply to newly seeded lawns. Wait four months after application before reseeding treated area.