Spectracide Weed Stop For Lawns Concentrate kills more than 460 types of weeds as listed and it wonÆt harm your lawn when used as directed. Use it to treat your lawn including bluegrass fescue Bermuda perennial ryegrass and zoysia (do not apply to zoysia just emerging from dormancy). This formula kills by contact down to the root with visible results in as little as 3 hours. Available as a dilutable concentrate and as a 40 ounce ready-to-spray concentrate with a QuickFlip sprayer that attaches to your garden hose. Apply Spectracide Weed Stop For Lawns Concentrate when temperatures are between 45 and 90 degrees. Spray until wet to control weeds. Do not apply when daytime temperatures are above 90 degrees because lawn injury can occur. Read the entire label before using.