Make troublesome lawn weeds a problem of the past. Roundup for lawns is a ready-to-use tough weed killer for Northern grasses that kills weeds, roots and all (when used as directed), with up to 3 month weed control (as listed). This product kills 253 types of weeds (see inside booklet for weed list), including crabgrass, dandelion, clover, yellow nutsedge, poison ivy, chickweed, oxalis, and purslane. In addition, it starts working immediately and is rainproof in 3 hours. Roundup for lawns is for use on northern grasses, including kentucky bluegrass, perennial ryegrass, fescue spp. including tall, red, and fine leaf fescues, and zoysiagrass. For best results, apply this product to actively-growing weeds during the early growth stages. Use in the spring or fall when daytime temperatures are between 45F and 90F. The trigger sprayer lets you treat weeds with a squeeze of the handle. Do not allow people or pets to enter the treated area until sprays have dried.