When is it safe for my children to play out again after using Roundup products?

Yes, you can. Just  keep them out of the area while you are using Roundup and then, once the spray is dry, you can let them re-enter. Roundup itself poses no risk to human health, when used in accordance with the label. However, you don't want your children or pets to walk through a treated area and then onto your lawn, as the lawn will be damaged. Roundup is very effective on grass!