How Long After Using Weed Killer Can I Fertilize Lawn?

To keep your lawn looking well-maintained, lush and green, you need to fertilize it and occasionally to use weed killer. Follow specific instructions on each of the packages or bottles containing the weed killer and fertilizer. Apply each solution on a sunny day when there is not a prediction of rainy weather for several days, because this helps the chemicals soak in, dry completely and do the work they are designed to do.

Natural Fertilizers and Weed Killers

If at all possible, use natural or organic weed killers and fertilizers to protect wildlife, pets and children from getting sick from eating, inhaling or licking chemicals designed to kill pests and encourage the growth of plants. Also, use a spray instead of using pellets or granules to cut down on the chance of an animal or human picking up the herbicide or fertilizer and ingesting it.

Close Application

You can apply weed killer and fertilizer within days of each other. Sometimes, you can apply them on the same day, depending on the needs of your lawn. For example, if you have only a few weeds in the yard, spray those specific plants and wait about 30 minutes. Then fertilize the yard, avoiding the plants and the area around the plants. You want the weed killer to have about two days to dry and to work before fertilizing your yard. For irksome weeds, wait until they are dead before you fertilize.

When to Fertilize

Herbicides place stress on your lawn, so always apply them first. Then set up a regular schedule for fertilizing your lawn. Always water your lawn before applying weed killer. Then fertilize about four times a year. A good schedule is to fertilize in April or May for the first period, in mid-June for the second period, in September for the third period and in November for the last period.

Safety Tips

When you are spraying or applying fertilizer -- or when a professional is applying it -- you will need to avoid getting close to any outdoor gates, cages or runs where your pets routinely spend time. The same goes for doghouses and pet playground areas. If fertilizer has not completely dried, curious furry ones can meddle in sprayed plants and become sick.