QuestionsHow to growFlowersBorder Perennial FlowersRound Up on empty flower beds 0 Vote Up Vote Down Rosaleen Carvill asked 14 years ago How soon after spraying with Round Up could dogs be let out in the garden? 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 7 years ago Roundup is harmless to animals, but normally people wait until it dries, or 12 hours.