Preen 9 lb. Lawncare. Covers 2,500 Sq.Ft. This easy one-step application for spring lawn care stops crabgrass all season and can be applied up to 4 weeks after crabgrass emerges. It kills dandelions and up to 250 other tough lawn weeds as listed, to the root. Feeds your lawn for up to eight weeks with a zero-phosphorus 24-0-6 formula. Do not use this product on St. Augustine grass, Colonial Bent grass, Dichondra or Carpet grass as serious lawn injury will result. For use on established bahiagrass, bermudagrass, buffalograss, fine fescues, Kentucky bluegrass, perennial ryegrass, tall fescue and zoysiagrass.