When to Fertilize Your Lawn

The best time to fertilize your lawn is during your grass’s growing season, and that means your first fertilizer application should be around April — no matter whether you have a warm-season grass or cool-season grass.

The exact timing varies by climate. For example, lawns in South Florida grow year-round, while grass in Maine needs lawn food only in April and August to September. Also, pay attention to the weather report, keeping a keen eye on rain.

So check the weather report and grab your fertilizer and fertilizer spreader — unless you hire a local lawn fertilization service to handle this lawn care task. Yes, with Lawn Love a local lawn fertilization pro is just a click away.

Learn the optimal timing for lawn fertilization tailored to your specific grass variety, climate, region, and fertilizer choice. This comprehensive guide draws on expert knowledge to help you achieve a lush, healthy lawn.

Lawn fertilizer schedule by grass type

Lawns need a lot of love to grow, so the best time to fertilize it is at the start of your grass’s growing season. 

Cool-season grass

With bimodal growth, cool-season turf grows in spring and fall. Thus, the cool-season lawn care calender calls for fertilizer in early spring, then again in late summer or early fall. 

“Fall is an important time to soil test, inter-seed, fertilize, and provide inputs to support optimal growth,” explains Becky Bowling, of the University of Tennessee, about caring for cool-season grass. “Particularly when air temperatures are between 60 and 75 degrees.”

Common cool-season grasses: Kentucky bluegrass, tall fescue, fine fescue, and perennial ryegrass. If you’re unsure about your grass type, read our guide or contact a local lawn care pro for your fertilization needs.

When to fertilize in spring	When to fertilize in fall
March to May	August to November
After the last freeze day	About six weeks before the first frost
Air’s steadily between 55 and 75 degrees

Warm-season grass

Since warm-season grass grows in warmth and goes dormant in the winter, it needs the biggest nitrogen boost when it greens in the spring. Additionally, the warm-season lawn care calendar calls for summer fertilization.

When it comes to fall fertilization, Bowing recommends “a final nitrogen application about six to eight weeks before the historic first frost date to try to prevent deficiency.”

Research indicates that lawns with an off-season nitrogen deficiency “may experience delayed green-up and challenges associated,” she explains.

Common warm-season grasses: Zoysiagrass, Bermudagrass, St. Augustinegrass, centipedegrass, buffalograss, Bahiagrass, and carpetgrass.

When to fertilize in spring	When to fertilize in summer
April to June	July to September
After spring green-up	Six to eight weeks after the last application

Best weather for lawn fertilization

The ideal time to fertilize is when temperatures are between 55 and 85 degrees, and light rain is expected within 24 to 48 hours of application. Avoid fertilizing during drought conditions or when heavy rain is forecast, as this can lead to nutrient runoff or lawn stress.

Below, I’ll explore each factor in more depth.

Ideal temperature for fertilizing grass

Ideal soil temperature	≥ 55 degrees
Air temperature: Cool-season grass	60 to 75 degrees
Air temperature: Warm-season grass	75 to 85 degrees

It’s best to apply grass fertilizer when the soil is at least 55 degrees. Also, avoid lawn fertilization in extreme temperatures:

• Excessive heat: Turf tends to decline in extreme heat, making it a bad time to apply fertilizer. Doing so impedes grass’s health and may lead to fertilizer burn, dehydration, or discoloration. Additionally, lawns consume less nutrients, allowing weeds and fungi to eat the excess.

• Freezes: It’s futile to fertilize when it’s frigid because grass fails to take in much of the nutrients. Additionally, excess fertilizer may get caught in frozen ground and then pollute run-off water. 

Fertilizing grass during rain

When faced with heavy rain and moisture, fertilizer often washes away with run-off water. In addition to minimizing benefits, this potentially pollutes nearby waterways. Before applying fertilizer, check the weather report for rain:

• Fertilizing before rain: Heavy rain within two days will likely wash away much of the nutrients.

• Fertilizing after rain: Although some fertilizers work best when the ground is mildly moist, applying fertilizer when it’s overly wet is wasteful. 

According to Dawn Pettinelli of the University of Connecticut, it’s best to fertilize when you’re expecting light rain, and the grass is dry. However, ideal moisture depends on the product, so carefully read your fertilizer’s label. 

Fertilizing grass during drought

Like you and me, grass prefers a drink with its meal. Hence, it’s best to avoid fertilizing during droughts. Otherwise, excessive nitrogen can burn the grass. Additionally, lawn weeds may flourish after consuming your lawn’s leftovers. 

However, if you can’t wait for rain, reduce the amount of nitrogen applied and avoid rapid-release fertilizers. Instead, seek a potassium-rich formula to enhance turf’s drought tolerance. 

When to fertilize by location

Regional timing matters for fertilization because grass varieties and soil conditions differ across climate zones. Northern regions have shorter growing seasons, while southern lawns may need year-round nutrients. Understanding your local ecosystem helps you build a healthier, more resilient lawn.

The table below shows the general timeframe when fertilizer can be applied by location.

City	Fertilization period
Austin, TX	March to April, October
Jackson, MS	March to June
Miami, FL	Year-round
New York, NY	April to November
Omaha, NE	May to June and August to October
Phoenix, AZ	April to September
Portland, ME	April, August to September
Richmond, VA	April to November
Salt Lake City, Utah	April to October
San Francisco, CA	March to May and September to October

My tip: I spoke with grass guru Amanda Folck, an extension educator at the University of Nebraska. She recommends homeowners, “Always refer to resources in your respective state’s extension outreach or neighboring state outreach for more specific guidelines in your specific area.”

When to apply different types of fertilizer

Timing fertilizer applications is crucial because different grass growth stages require specific nutrients. Applying the wrong fertilizer at the wrong time can damage grass, waste money, and potentially harm the environment through nutrient runoff or leaching into groundwater.

• Starter fertilizer: Apply starter fertilizer when planting new grass.

• Slow-release fertilizer: At the beginning of its growth season, most lawns need a nitrogen-rich, slow-release fertilizer that contains NPK and organic matter. 

• Quick-release fertilizer: Apply during periods of optimal growth. Quick-release fertilizers work best at the start of the growing season and should never be used during drought or extreme temperatures. 

• Winterizer: Turf often triumphs with winter fertilizer applications in late fall, before the first frost. 

FAQ about lawn fertilization

When to call a lawn fertilization pro

Hiring a pro is best if you’re short on time or lawn care savvy. Lawn Love puts local lawn fertilization pros at your fingertips. Just click and book lawn fertilization services. What could be easier?

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