QuestionsHow to growLawnsWeedsLawn Weedkiller 0 Vote Up Vote Down Derek Dolan asked 14 years ago How long should I keep the kids off the lawn after applying a selective lawn weedkiller for weeds, daisies etc? Also is it better to cut a lawn prior to its application and is there any problem applying it in the evening time. 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 7 years ago Mow about three days before spraying and do not mow again for a week or so and dump the mowings separately to one side. Spray in the evening and follow the instructions on the pack carefully.