Roundup 30 oz. Ready-to-Use Weed & Grass Killer. It kills the toughest weeds and grasses down to the root. The formula is ideal for use in and around vegetable gardens, flower beds, tree rings, and mulched beds, as well as on cracks in driveways, walkways, and patios. This convenient, no-mix formula is rainproof in just 10 minutes, and visible results in 3 hours. Active ingredients; 2% Glyphosate; 2% Pelargonic acid and related fatty acids.