Stop weeds before they sprout with Green It corn gluten weed preventer. This ready-to-spray corn based pre-emergent derived from locally grown corn and manufactured in North America. It works by releasing organic dipeptides (proteins) into the soil to prevent weed seeds from establishing. Liquid corn gluten is a concentrated patented formula which works on weeds such as dandelions, crabgrass and clover. To apply simply attach your hose to the included hose-end sprayer attachment, shake well and turn the dial to the "on" position. No mixing or calibration is required, natural weed control has never been this easy and affordable.