Compare-N-Save® Concentrate Grass & Weed Killer 1 Gallon Bottle - 75324 Get to the root and kill grass and weeds with Compare-N-Save 41% Glyphosate Concentrate Grass and Weed Killer. Use for lawn or garden replacement, on patios, walkways, or in and around fences and gardens to remove unwanted grass and weeds. The 1 gal. container will treat over 25,000 sq. ft. with visible results in as little as 2 to 4 days. Rainfast in 2 hours. Bilingual consumer friendly label. Kills all grass and weeds.