Highlights
When to fertilize your lawn depends on your grass type and fertilizer product.
Treat your lawn when grass is growing, not dormant.
Fertilize in late winter or early spring. Then repeat six to eight weeks later.
Pace treatments with slow-release fertilizers.
If you want the kind of ultra-green, lush grass that will literally have your neighbors green with envy, you’ll want to fertilize your grass—but it’s a delicate balance. You’ll need to know when to fertilize your lawn and how often for the best results.
Some homeowners choose to hire a local lawn fertilization service and avoid the fuss, but if you want to roll up your sleeves and do the job DIY, there are a few things you need to know. This guide will tell you when to fertilize your lawn, no matter where you are in the United States.
When to Fertilize Your Lawn
You should only fertilize your lawn when it’s actively growing—but that changes based on your climate and the type of grass. The typical growing season falls somewhere between the last spring frost and first autumn frost.
Time of day is another important factor. The best time for lawn fertilizer is in the morning when your grass is cool and slightly damp—just make sure it isn’t too damp. Watering a damp lawn can lead to fertilizer burn since it allows granular fertilizer to stick to grass blades.
How Often to Fertilize Your Lawn
As a rule, you should fertilize your lawn at least twice a year. It may need more or less, depending on your soil quality, climate, and weather. For example, heavy and prolonged rain can wash fertilizer away, while fertilizing during high summer heat can burn your grass. Shaded lawns generally need less nitrogen than lawns in full sun.
Identifying Your Grass Type
Before you can decide when to fertilize your lawn and get on a regular schedule, you need to know what type of grass you’re dealing with.
Grasses in the United States are categorized as cool-season or warm-season grass:
Cool-season grasses grow in the Northern U.S. Their peak growing season is spring and fall, while they go dormant in summer (when temperatures are very high) and again in the winter.
Warm-season grasses grow in the Southern U.S. Their peak growing season is midsummer, while they go dormant in fall.
If you live in a transitional zone, you may have both types of grass. You’ll notice that warm-season grasses turn brown after the first fall frost, while healthy cool-season grass stays green year-round. If you’re still not sure what type you have, a lawn care service in your area can help.
Lawn Fertilizer Schedule for Cool-Season Grass
Cool-season grass (like the ever-popular ryegrass or tall fescue grass) grows when temperatures are consistently between 60 and 70 degrees Fahrenheit. In other words, the ideal growing seasons are fall (the primary growing season) and spring (the secondary growing season). You’ll need to feed this type of grass 1 to 2 pounds of nitrogen-rich fertilizer per 1,000 square feet, split between growing seasons.
Follow the lawn fertilizer schedule below to learn the best time to fertilize your lawn:
Spring
If you fertilized well in the fall, you may not need to fertilize in the spring. You can hire a local soil testing company to make sure. If you do need to feed your lawn, apply a slow-release fertilizer in late spring, after you’ve given your grass time to snap back from winter dormancy.
Summer
Do not fertilize cool-season grass in the summer.
Fall
Depending on temperatures, fertilize a second time in late summer or early-to-mid fall. This should be the heftiest fertilization since it’s meant to support the most active growth and foster healthy root growth. Fertilize early enough to allow several weeks before the first hard freeze when it jumps back into dormancy.
Winter
Do not fertilize cool-season grass in the winter.
Lawn Fertilizer Schedule for Warm-Season Grass
Warm-season grass (like Bermuda grass or Zoysia grass) grows when temperatures are consistently between 80 and 95 degrees Fahrenheit. As such, the growing season is anywhere from late spring to late summer.
Depending on your climate and soil quality, you’ll need to fertilize warm-season grass between two and four times a year (or about every four to eight weeks during the growing season). Make sure your lawn gets 3 to 4 pounds of nitrogen-rich fertilizer per 1,000 square feet, spread across the growing season.
Use this lawn fertilizer schedule for the best time to fertilize your warm-season grass:
Spring
Fertilize your lawn with a slow-release fertilizer six weeks after the last spring frost. Before you fertilize, make sure your grass is out of dormancy. A good way to tell is color and growth. If it’s green and you’ve mowed it at least twice, you’re good to go.
Summer
In late summer or early fall, you can fertilize your warm-season grass a second time. This will help strengthen your grass and prepare it for winter dormancy. This time, use a highly soluble nitrogen fertilizer.
Fall
In the warmest climates, the growing season is extended. You can give your lawn another, lighter feed of nitrogen-based fertilizer about 45 to 60 days after your summer or early fall feed.
Winter
Do not fertilize warm-season grass in the winter.
When Not to Fertilize Your Lawn
Overfertilization can thwart new growth and leave your lawn vulnerable to pests and disease. As a rule, you should never use more than 1 pound of nitrogen per 1,000 square feet in a single feed. Slow-release fertilizer is gentler because it feeds your lawn over a period of months.
To avoid overfertilization, never fertilize:
When your grass is dormant
During extreme heat
During drought
Before a heavy rain
Right after a heavy rain
