Ortho 1-Gallon GroundClear Weed & Grass Killer. This ready-to-use wand begins working immediately, providing quick and visible results in just 15 minutes. Ideal for use on patios, pavers, and landscapes, it effectively kills all types of weeds and grasses. OMRI listed for organic gardening, this rainproof formula is safe for use within 2 hours upon drying. The active ingredient is Ammonium Nonanoate.