Spectracide Weed & Grass Killer is pre-mixed and ready to use for spot treatment of weeds and grasses. Use it on and around patios, walkways and flower beds. This formula is rainproof in 15 minutes?rainfall or watering after 15 minutes won't wash away effectiveness. Spectracide Weed & Grass Killer kills down to the root and delivers visible results in as fast as 3 hours. This product kills weeds and grasses as listed, including chickweed, plantain, dandelion, annual bluegrass and clover. Plant new flowers, trees and shrubs in the treated area after just 1 day. When used as directed, Spectracide Weed & Grass Killer works the first time, every time! For best results, apply during warm, sunny weather when the temperature is over 60 degrees.