Here’s When You Should Fertilize Your Lawn for Healthier, Greener Grass

A lush, healthy lawn doesn’t happen by accident. It’s the result of thoughtful preparation—and fertilizing at the right time is a key component. Fertilizer gives your yard the nutrients needed to grow healthy and green. But applying it at the wrong time can be ineffective or even harmful to your lawn. Understanding your grasses’ growth cycle, the climate, and expert-backed timing strategies can help you achieve the best possible results. Here’s when and how you should fertilize your lawn.

Why Timing Matters

Most people wonder how often they should fertilize their grass, but knowing when to fertilize can be an even more complex question. Grasses go through natural cycles of active growth, stress, and dormancy. Fertilizing when your grass is ready to absorb and use nutrients ensures the fertilizer is working efficiently—supporting stronger roots, thicker blades, and better resistance to drought and disease.

“Spring is the time for complete lawn maintenance,” says Courtney Klosterman, home insights expert at Hippo Home Insurance. “Reseeding, fertilizing, and regularly mowing your lawn helps boost the curb appeal of your home and give grass time to grow before the summer sun sets in.” Starting in spring prepares your lawn for the long growing season ahead, but that’s just the beginning.

Give outdoor plants some love during this time, too, but double just make sure to follow the specific timing and fertilization needs for each specific plant.

Cool-Season vs. Warm-Season Grasses

Before planning your fertilization schedule, it’s important to determine whether you have cool-season or warm-season grass. Cool-season grasses, such as Kentucky bluegrass, ryegrass, and fescues, thrive in the cooler temperatures of spring and fall. In contrast, warm-season grasses, including bermudagrass, zoysiagrass, and St. Augustine, grow most actively during the heat of summer. Each type has a slightly different ideal fertilization window based on when it is naturally growing and where you live.

When to Fertilize Cool-Season Lawns

Homeowners with cool-season lawns should plan to fertilize twice a year: once in the early spring and again in the fall. According to Marc Mayer, director of technical operations, and Brian Feldman, senior director of technical operations, at TruGreen, most people should plan to apply fertilizer from late summer through fall to strengthen lawn roots before winter. Both experts emphasize that fall feeding helps your lawn store energy and build resilience for the cold months ahead.

However, spring feeding plays an equally critical role. After winter dormancy, cool-season grasses wake up hungry. Fertilizing in early spring, around March or April, jumpstarts growth and quicker, thicker coverage. Spring fertilizers for cool-season grasses should contain a balanced amount of nitrogen to promote healthy growth.

Apply fertilizer in early mornings or late afternoons, when temperatures are cooler. Doing so limits heat stress and ensures better nutrient absorption.

When to Fertilize Warm-Season Lawns

Warm-season grasses have different rules to grow by. These grasses begin to green in late spring and grow most actively during peak summer months. “Summer is peak season for warm-season turf types, and while these grasses still need fertilizer in the spring and fall, they grow more actively in the summer when they’ll need most of their nitrogen-rich fertilizer,” says Roger May, PhD, the Michigan region technical manager for TruGreen.

For homeowners with warm-season lawns, late spring is the ideal time to start fertilizing. When grass begins to green and temperatures consistently rise, a fertilizer rich in nitrogen can help promote rapid growth and dense coverage. Throughout the summer, light to moderate feedings help sustain this growth. However, as summer winds down and cooler fall temperatures approach, it’s important to shift strategies.

Dr. May stresses that in the fall, it’s crucial to focus on applying potassium, which strengthens grassroots and prepares the turf for winter dormancy. For example, bermudagrass should be fertilized with a nitrogen-free, potassium fertilizer in early fall before dormancy hits. This shift ensures energy is directed to root health rather than top growth, making for a healthy spring comeback.

When Weather Conditions Affect Fertilization

While knowing the season is important, paying attention to daily weather conditions is just as critical for effective fertilization. Ideally, fertilizer should be applied on mildly warm days when temperatures range between 50 and 85 degrees Fahrenheit. The soil should be slightly moist—not dry and cracked, nor overly saturated.

Avoid fertilizing right before a heavy rain. Downpours can wash fertilizer off the lawn and into drains, wasting your efforts and potentially doing more environmental harm than good. Light watering after application, however, can help fertilizer penetrate the soil and reach roots that need it most.

Timing fertilizer applications for early morning or late afternoon is best. Midday fertilization during the heat of the day can cause fertilizer burn and stress the grass. Cooler times of day allow more nutrients to be absorbed rather than evaporated.

Special Timing Considerations

If you’ve recently seeded a lawn, then your fertilization approach may need to be slightly adjusted. New lawns generally benefit more from starter fertilizers that are higher in phosphorus, which promotes strong root development. However, reading the product label for quantity is important, as young grass is more sensitive to over-fertilization.

Similarly, lawns that are stressed from drought, disease, or heavy foot traffic require a gentler approach. In these cases, it’s better to address the underlying stressors before aggressively fertilizing.

Professional Help Can Make a Difference

Although general guidelines work for many lawns, sometimes professional care is what it takes to make a good lawn a great one. Lawn care and gardening experts can take the guesswork out of diagnosing ideal timings for your climate and growing conditions. And they can help you avoid becoming your garden’s worst enemy.

Klosterman also points out that “a lawn care professional can help homeowners plan a proper fertilization regimen that’s right for their lawn’s unique needs.” Pros often test the soil for pH levels and identify vital missing nutrients. With this information in hand, you can ensure that the fertilizer you purchase addresses your lawn’s specific requirements. Pros can even set up a recurring maintenance schedule to ensure you never miss fertilizing season.