We all know the weather can be finicky. Just because it’s late October, and you’ve already had two frost doesn’t mean it won’t warm up to 70 degrees again and you won’t still have to mow. So, let’s say you spray for dandelions, and then your grass looks like it needs a good once over before putting away the mower for the winter. It’s safe to do so after 24-48 hours. You don’t want anything to disturb the herbicide or prevent it from proper absorption. It’s also not safe for you to walk on it for about 24 hours, so it’s best to wait a day or two.