How Often to Fertilize Your Lawn—and the Best Time to Do It

Fertilizer keeps lawns healthy and luscious—here's the right way to do it, according to lawn care pros.

Beautiful Home With Green Grass Yard — Credit: adogslifephoto / Getty Images

Fertilizer is an essential part of lawn care. It provides the nutrients your grass needs to thrive—it also crowds out weeds, improves resistance to disease and drought, and promotes a healthy root system. However, over-fertilizing your lawn can do more harm than good. To ensure you get this maintenance task right, we spoke to lawn care experts to learn how often you should fertilize your lawn, plus when to do it for best results.

Craig Elworthy, founder of Lawnbright, a lawn care subscription service
Jason McCausland, national technical director of Weed Man, a lawn care and weed control service

How Often to Fertilize Your Lawn

How often you should fertilize your lawn depends on a few factors, including the type of grass you have, the type of fertilizer you're using, and how much you apply. As a general rule of thumb, it's ideal to fertilize your lawn about three to four times a year, says Craig Elworthy, founder of Lawnbright.

When to Fertilize Your Lawn

The time of year you fertilize your lawn will depend largely on the broad category of grass you have, which can be broken down into cool-season and warm-season grasses.

Cool-Season Grasses

The best time to fertilize cool-season grasses, like Kentucky bluegrass and fescues, is in the fall. This is because fall is when your lawn is trying to put on root mass and store nutrients before winter. "It will respond well to any fertilizer applied during this time, and the temperatures in fall allow it to grow quickly and fill out bare spots," says Elworthy. You can fertilize your lawn a few times during the fall, depending on the type of fertilizer you're using.

The next-best time to fertilize cool-season grasses is in spring. But keep in mind that during spring, your lawn is going through a natural flush and doesn't require as much fertilizer. Just once during May is enough. Avoid fertilizing cool-season grasses during summer, when the lawn is under significant stress; encouraging growth can stress it even further.

Warm-Season Grasses

Warm-season grasses, like Bermuda grass and centipede grass, have a different growth pattern and should be fertilized in late spring and summer. "Unlike cool-season lawns, the late spring and summer is a high growth period for warm-season lawns, and they love to be fed during this time." Fertilize warm-season grasses once a month from May to about August, depending on the type of fertilizer you're using.

Best Time of Day to Fertilize Your Lawn

While the time of day you fertilize your lawn may vary based on personal preference, Elworthy recommends fertilizing in the morning. "Each application of fertilizer should receive at least a 1/4-inch of water to get down into the root zone," he says. "I don’t like to leave the grass wet overnight because it can cause disease and fungus, so watering during the morning will give it the most amount of time to dry out before evening."

Which Fertilizer to Use and How Much

The type of fertilizer you use comes down to personal preference, but generally, using light applications of an organic, slow-release fertilizer is ideal. Slow-release fertilizers feed the roots over an extended period, says Jason McCausland, national technical director of Weed Man. Always follow the product's recommendations for dosage, but light applications eliminate the risk of fertilizer burn and damage and allow for more even growth, says Elworthy.

Frequently Asked Questions

How often is too often to fertilize?

How often you fertilize your lawn depends on the type of grass you have and the product you are using. For example, a heavy synthetic fertilizer can burn your lawn and significantly alter the pH and the salt content if used too much. On the other hand, a natural fertilizer like grass clippings can be used once a week, says Elworthy.
What happens if you don't fertilize your lawn?

Your lawn will not survive without fertilizer, says McCausland. There are some nutrients in the soil, but not enough to sustain turf grass over an extended period of time without some fertility.
How long should you wait between fertilizing?

How long you wait between fertilizing depends on the amount of nitrogen you’re applying each time. You will need to wait longer if you're using a product that's high in nitrogen.
Should I fertilize my lawn before or after the rain?

If you see some rain on your weather forecast and you're wondering whether you should go ahead and fertilize your lawn or not, hold the hose: It's actually best to wait a couple of days after you get rain to fertilize your lawn. Waiting helps the water soak deeply into your yard, which will help the fertilizer fully absorb later.