When to Fertilize Your Lawn

Stake sign in grass that reads "Fertilize Your Lawn"

If you fertilize your lawn at the wrong time of year, you might as well not fertilize it at all. So, what is the right time of year? That depends on your grass type’s growing season. This guide goes into detail about when to fertilize your lawn, whether you have cool-season or warm-season grass.

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How Often Should You Fertilize Your Lawn?

Fertilize your lawn two to four times each year. Use a slow-release fertilizer if possible. Slow-release fertilizers add nutrients to the soil gradually over time, so the results last longer, and you don’t have to apply fertilizer as often. 

No matter what type of grass you have, your first fertilizer application should be in early spring when the lawn greens up after winter dormancy. After that, though, your fertilization schedule will depend on your grass type

Map of the United States showing cool-season grass, warm-season grass, and transition zones.

When to Fertilize Cool-Season Grasses

Cool-season grasses grow most actively in the cooler temperatures of spring and fall, so those are the best times to fertilize. Cool-season grasses grow in the northern portion of the U.S. and can’t survive the extreme heat of southern summers. 

Lawn Fertilizer Schedule for Cool-Season Grasses

Early spring: When the grass greens up after winter, usually late March or early April depending on the year and where you live

Early fall: The beginning of the second active growth season, usually early September

Late fall: At least 6 weeks before the first expected frost in your area, usually late October or early November depending on the year and where you live

  • Kentucky bluegrass 
  • Fescues 
  • Perennial ryegrass 

When to Fertilize Warm-Season Grasses 

Warm-season grasses grow most actively in summer. It’s best to give warm-season grasses a fertilizer boost at the beginning of their growing season in late spring and again in summer. 

Lawn Fertilizer Schedule for Warm-Season Grasses

Early spring: When the grass greens up after winter, usually late March or early April depending on the year and where you live

Early summer: When grass growth speeds up, but before the onset of intense midsummer heat, usually early June 

Early fall: At least 6 – 8 weeks before the first expected frost, usually sometime in September 

  • Bermuda
  • Zoysia
  • St. Augustine 
  • Centipede
  • Carpetgrass 
  • Bahia 

FAQ About When to Fertilize Your Lawn

1. Should you fertilize before or after cutting the lawn?


Fertilize right after mowing the lawn so the fertilizer has the most time possible to break down into the soil before it’s time to mow again.

Pro Tip: When you mow the lawn, leave the mulched grass clippings to break down into the soil to add even more nutrients and improve soil structure. 

2. What time of day should I fertilize my lawn?


Fertilize your lawn in the morning or early evening when the sun isn’t so intense and temperatures are cooler. Fertilizing your lawn when the sun is on full blast in the middle of the day can lead to burning the grass, especially in summer. 

3. When should you seed and fertilize your lawn?


The best time to seed cool-season grass is early fall, when the soil temperature is between 50 and 60 degrees. Plant new seeds at least 45 days before the first expected frost in your area so the seedlings have time to establish before winter. 

The best time to seed warm-season grass is in late spring or early summer, when the soil temperature is between 65 and 75 degrees. Don’t wait too late into the year, or the intense heat of midsummer could scorch the sensitive new grass before it has time to establish.

Mix starter fertilizer into your soil before planting new grass seeds. Add another application of starter fertilizer about 6 – 8 weeks after planting.

How to Fertilize Your Lawn

The first step in fertilizing your lawn is figuring out when to do it. Check!

Next, you have to decide which lawn fertilizer is best for your lawn’s needs. How much nitrogen, phosphorus, and potassium does your soil need? Is granular or liquid fertilizer better for you? What are the pros and cons of organic fertilizers? Find the answers to these questions in our guide to How to Choose the Right Fertilizer for Your Lawn.

Once you’ve purchased your fertilizer, you’re ready to get this show on the lawn. For advice on best practices, see our step-by-step walk-through of How to Fertilize Your Lawn

When you’re sick of working in your yard, LawnStarter’s local lawn care pros are here to help. They’re available for weekly or bi-weekly lawn mowing service. 

Main Photo Credit: Shutterstock

Jordan Ardoin

Jordan Ardoin

Jordan Ardoin is a writer and indoor plant enthusiast hailing from Florida. In her spare time, she enjoys chasing her two cats around the house and trying to keep her houseplants alive.