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Should You Fertilize Your Lawn in Summer? Experts Say Yes—But Only If You Do This

Fertilizing your lawn in the spring is a great idea. But that shouldn't be the only time you replenish your soil's nutrients throughout the year. “Many homeowners only treat their lawn once a year, but for best results, you should aim for four applications annually, spaced throughout the seasons,” says Cameron Brown, merchant of seed and fertilizers at The Home Depot.

“As the season progresses, additional feedings—such as a summer formula that supports heat and insect protection, followed by a fall or winterizing fertilizer—help maintain thickness, color, and overall lawn health,” says Brown. “When used together, this approach helps create a lawn that naturally crowds out weeds over time.”

Plus, a dose of summer feeding can help strengthen your lawn to stand up to the stress of both the summer heat, lower rainfall, or even drought that can further cause stress to grass. However, it’s essential to know what to feed your lawn during the summer for optimal health. Keep reading to find out about the best fertilizer types, ideal fertilizer timing, summer lawn fertilizer application tips, and common summer fertilizer mistakes to avoid.

Does Your Lawn Need Fertilizer in Summer?

Grass needs nutrients throughout its growing cycle, from spring through the fall. Unfortunately grass doesn’t have access to all of the nutrients it needs from most soils. It’s important to continue to fertilize your lawn about every 6 to 8 weeks throughout the summer months to support and maintain a lush lawn.

“A strong program starts with a pre-emergent in early spring to prevent weeds like crabgrass before they appear,” says Brown. “From there, a weed-and-feed product helps address any weeds that have already emerged while also nourishing the lawn.” He also then recommends “a summer feeding, and a fall or winterizing treatment. Staying consistent with this schedule makes a noticeable difference in lawn thickness, color, and overall durability.”

Cool‑Season vs Warm‑Season Grass

While all grasses benefit from fertilizer, not all grasses have the same fertilizer needs. There are cool-season grasses like fescue, ryegrass, and Kentucky bluegrass that enjoy fertilizer after the soil temperature reaches 55 degrees. Warm-season grasses like zoysia and Bermuda thrive when fertilizer is applied during the months when the soil temperature is above 70 degrees.

“For cool-season grasses (common in northern states), early spring is appropriate for a light feeding once the grass begins actively growing. For warm-season grasses (common in southern regions), it’s best to wait until the lawn is fully green and actively growing before fertilizing,” says Lou Manfredini, Ace Hardware’s home expert.

Cool-season grasses tend to slow their growth during the hottest days of the summer and can benefit more from soil food that helps balance the pH than from the same fertilizer used in the spring. Using the same springtime formula could potentially burn the lawn during the summer months. However, warm-season grasses are thriving during the hottest temperatures and benefit from additional fertilizer feedings.

Signs Your Lawn Is Actively Growing

Experts agree that you should only feed your lawn when it’s actively growing. But how do you know that it’s growing? You can test the soil temperature. If the soil is above 55 degrees Fahrenheit and you have cool-season grass, then your grass is likely out of dormancy. For warm-season grasses, make sure it’s about 70 degrees. If you don’t have a soil thermometer, your local university probably can tell you the current soil temperature for your area.

You can also wait to see the signs from Mother Nature, like flowers popping up through the ground, green color returning to the lawn, grass recovering well after a mow, and a lack of brown patches.

Best Summer Lawn Fertilizer Types

The best summer fertilizer for lawn health could be any of a variety of options as it depends upon the type of grass, location, and soil chemistry. “The answer depends on your specific circumstances,” says Isaac Mertz, Ph.D., regional technical manager of the Carolina region for TruGreen. “Each option has distinct advantages.”

All-Purpose Blends

If you are trying to establish a new lawn during the summer months, consider “all-purpose blends (10-10-10, 20-10-10),” says Mertz. They “contain nitrogen for leaf development, phosphorus for roots, and potassium for stress resistance.”

Slow‑Release Nitrogen Fertilizers

Nitrogen-concentrated fertilizers that are slow release are generally a much better option than quick-release fertilizers. “Slow-release nitrogen products—sulfur-coated urea, polymer-coated urea, products like Milorganite—gradually deliver nutrients, minimize turf damage, and need fewer applications over time,” says Mertz. There’s also a lower risk of accidental burning.

Lower‑Nitrogen Blends for Cool‑Weather

The summer heat can be a lot of stress on cool-weather grasses, so adding large amounts of nitrogen that promote growth can be too taxing on your lawn. It’s important to look for lower nitrogen blends (NPK of 7‑0‑20 or 12‑0‑24) to use during the summer months. The boost of potassium can help grass better handle the stress of summer heat and fewer rainy days than it experienced during the spring.

Organic vs Synthetic Options

Organic is the best bet for summer lawn fertilizers. “Organic fertilizers are generally less fast-acting and more expensive,” says George Carrette, owner and operator of EcoQuiet Lawn Care. “However, for a DIY gardener, organics offer a safety net—you won’t kill your grass if you spill a bit because they release nutrients slowly as they break down. Synthetic fertilizers provide a quick nutrient boost but require much more precision to avoid fertilizer burn.”

Plus, the fast-acting nature of synthetic fertilizers can be too intense for the summertime. If you want a quick-fix, it’s best to use a synthetic in the springtime. “Natural fertilizers—compost, manure-based blends, feather meal, Milorganite—enhance soil composition and microbial life with minimal burn risk, though effects appear more gradually,” says Mertz.

Synthetic fertilizers can give your lawn a quick boost in color, but they're also more likely to burn it, so avoid them in the summer when grass is already heat-stresed.

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NPK Ratios to Look For in Summer Fertilizers

All lawn fertilizers have an NPK ratio that describes what it is designed to do. Understanding what NPK (Nitrogen-Phosphorous-Potassium) means can help you select the right fertilizer for your lawn.

Essentially, NPK is a ratio of each nutrient based on weight. You’ll notice that it won’t add up to the weight of the package, as the rest of what’s inside the fertilizer package is filler. The filler is designed to bulk up the NPK and makes it easier to spread on the grass.

Nitrogen (N) helps grass have a green color and it helps with growth.
Phosphorus (P) supports root strength so it’s firmly anchored to the earth.
Potassium (K) increases grass’s stress resistance, which can be especially important in summer months.

Cool-season lawns

Experts say to minimize added nitrogen to your cool-weather grasses during the summer. Why? Nitrogen promotes more growth which can tax your grass’s resources during a time when it's already stressed from the heat. For cool-season lawns, choose low nitrogen to prevent too much growth and high potassium to aid with drought tolerance. Some experts suggest using iron to help keep summer lawns richly green without the growth that nitrogen can induce. Milorganite contains 2.5 percent iron.

Warm-season lawns

Unlike cool-season lawns that aren’t heat lovers, warm-season lawns thrive during the hotter months of summer. It’s ok to use a higher slow-release nitrogen mix during hot days. Just be sure to always fertilize when it’s the coolest part of the day, never the hottest.

When to Fertilize Your Lawn in Summer

Summer fertilizing schedules can vary based on the type of grass in your lawn, the temperature, and how often you water or how often it rains. The more water, the more fertilizer a lawn tends to want. Here are some summer lawn fertilization tips about when to fertilize.

Early Summer (June)

After spring fertilizing has completed, wait about 6 to 8 weeks until you fertilize again during June. Grass is actively growing, the soil is warm, and the grass needs nutrients to support it so it thrives. You may want to use the same formula as the spring fertilizer, but you may want to decrease the amount of nitrogen at this time if it’s hot and you have cool-season grass.

Mid‑Summer

About 6 to 8 weeks after the early summer fertilizer, you can choose to fertilize again if the lawn needs it. You may want to do a soil test to see if it is lacking specific nutrients before choosing a fertilizer, and you’ll likely need less at this time of summer. Just make sure to fertilize during the coolest part of the day to help reduce the risk of burns, and don’t fertilize if you are in a drought. This is a good time to choose a fertilizer like Milorganite that contains some iron, which helps with the green color but without the growth-inducement stress of nitrogen.

Late Summer (August)

If another 6 to 8 weeks pass and it’s still summer, you may want to follow up with another light application of fertilizer that is similar or the same as the mid-summer formulation. For warm-season lawns, fertilizing at this time can help your lawn transition into fall growth. Cool-season lawns usually benefit from fall fertilizer rather than another summer dose.

Mistakes to Avoid With Summer Lawn Fertilization

With all of the effort put into fertilizing a lawn, it’s a good idea to know about common mistakes you’ll want to avoid. First, don’t try to fertilize without the right supplies. “A good spreader is crucial. Use either a handheld, drop, or broadcast spreader depending on the size of your lawn,” says Manfredini. “Gloves and a mask are not bad ideas when applying the chemicals. Always follow the application instructions. More is not always better.”

Here is a quick list of common fertilizer mistakes:

Fertilizing during peak midday heat can increase burn risk.
Using too much nitrogen can weaken roots and stress the lawn.
Fertilizing drought‑stressed or dry lawns leads to grass damage.
Skipping water after application keeps nutrients on the grass blade tips, leading to burns.
Not wearing safety protection like gloves and a mask can put your health at risk.

Summer Lawn Fertilizer FAQ

Is it okay to fertilize a brown lawn?

No. A brown lawn is not actively growing. Always wait until growth resumes after a dormant winter before applying fertilizer. The soil temperature is usually 55 degrees or higher when grasses begin to grow again.

How often should I fertilize in summer?

Lawn experts recommend fertilizing most lawns about every 6 to 8 weeks while the turf is active. It’s important to test the soil to find out what nutrients are needed and to adjust the type of fertilizer and the NPK mix accordingly.

Can fertilizer burn grass in summer?

Yes, fertilizer can burn grass, especially during the hotter summer months if too much fertilizer is applied and especially if you are using a high nitrogen formula when it’s hot. It’s a good idea to choose a slow‑release formula during the summer.