The ideal time to dethatch your lawn is when your grass is actively growing, which depends on your climate and your grass type. In the South, where warm-season grasses are the norm, dethatch in late spring to early summer. In the North, you should dethatch your cool-season grasses like Kentucky bluegrass in early spring or early fall.
Dethatching too early or too late can put unnecessary stress on your grass, making it more vulnerable to pests, diseases, or bare spots. When you do it at the right time, your lawn recovers faster and grows back thicker, stronger, and healthier.
This guide will show you the best time to dethatch based on where you live. With the right timing and a few easy checks, you can dethatch without the guesswork and help your lawn stay neat, healthy, and strong.
The North
In the North, you almost certainly have a cool-season lawn like Kentucky bluegrass, fine fescue, or perennial ryegrass. The best time to dethatch lawns here is from late August through September.
Dethatching, while beneficial, is stressful on a lawn, but cooler temperatures and consistent rainfall provide good conditions for recovery after the stress of dethatching.
You can also dethatch in early spring, roughly mid-April. As Dr. J. Bryan Unruh, associate center director and professor at the University of Florida Extension, explains, “You want to dethatch prior to periods of active growth to ensure the lawn has the greatest chance of recovery before the onset of stress periods.”
Read more:
- The Best Time to Dethatch Your Lawn in Wisconsin
- When to Dethatch Your Lawn in Minnesota
- When to Dethatch Your Lawn in Michigan
The South
Most lawns in the South consist of warm-season grasses like Bermudagrass, St. Augustine, or Zoysiagrass. The best time to dethatch a warm-season lawn is late spring through early summer – May through June..
Dr. Unruh explains that spring and summer are the best times for dethatching because warm-season grasses are actively growing during these periods. He cautions against fall dethatching, when cooler temperatures, shorter days, and slower growth rates can make recovery more difficult.
One exception: Don’t dethatch during periods of extreme heat or drought. Your grass is already stressed during these times, and dethatching could stress it further and cause damage.
Read more: When to Dethatch Your Lawn in Texas
States in the middle
The central band of the U.S is called the transition zone. In these areas, both cool- and warm- season grasses work, and some lawns are a mix of both. The best time to dethatch here depends on the dominant grass type in your lawn.
- Cool-season grass: If your lawn is primarily a cool-season lawn, early fall is the best time for dethatching this type of turf.
- Warm-season grass: If your lawn is mostly warm-season grass, you should dethatch in late spring or early summer, once nights are warm and the grass is growing.
- Mixed grass: The best time of year to dethatch a mixed lawn depends on the peak growing season of the dominant grass. If the lawn has an equal mix of both, dethatch in early to late spring or in early fall.
Dr. Unruh explains that certain types of grass are more likely to develop thatch than others, especially warm-season varieties like Zoysiagrass and Bermudagrass. These grasses spread using both above-ground and underground stems, which break down slowly and tend to build up over time. He also points out that using a lot of lawn products, especially nitrogen fertilizer, can cause thatch to build up faster, which means you’ll need to dethatch more often.
Read more: Benefits of Dethatching Your Lawn
When to dethatch in specific weather conditions
As I said, dethatching is stressful, so you want to do it when the grass is strong. According to Ph.D. Peng Tian, assistant extension professor at the University of Missouri Extension, “Lawns should be dethatched only when conditions favor rapid turfgrass recovery.” Here are some weather and soil considerations to keep in mind when scheduling a dethatching:
- Soil moisture: Dethatch when your soil is moist but not waterlogged. If your soil is very dry, watering the lawn one or two days before dethatching can help achieve the right level of moisture. You want the thatch to come up easily but the soil to remain intact.
- Temperature and turf stress: Avoid dethatching when your lawn is under stress from heat or drought. These conditions make it much harder for grass to recover. The best temperature conditions for dethatching are moderate, pleasant days.
- Weather forecast: Check your upcoming forecast and give your lawn a cushion of good weather after dethatching. The lawn needs a few weeks of decent growing conditions to recuperate. Avoid dethatching right before a major heat wave, a drought spell, or a deep cold snap. If the forecast shows extreme conditions, it’s better to wait for a milder period.
Read more: How Much Does Lawn Dethatching Cost in 2025?
FAQ about when to dethatch your lawn
A simple ruler or measuring tape will do the trick. You should see three layers: the grass on top, the thatch layer in the middle, and the soil and grass roots at the bottom. Measure in several places to get an average.
Yes, you can dethatch and aerate at the same time. In fact, it’s generally preferred. Do both during peak growing season for your grass type. During this time, your grass can handle the rigors of dethatching and aeration and recover faster afterward. Always dethatch first to clear debris and expose the soil.
Read More: Can You Dethatch and Aerate at the Same Time?
A young lawn typically doesn’t have enough thatch buildup to require dethatching within the first couple of years. After two years, you can check for thatch by cutting out a small section of grass and looking closely at the space between the soil and the grass blades.
The next step to a fuller lawn
Dethatching is a solid first step; for even better results, follow up with aeration and overseeding. LawnLove can connect you with local professionals, so you can strengthen your lawn, fill in bare spots, and get it looking its best.
Sources:
Dr. J. Bryan Unruh. Associate Center Director and Professor. Turfgrass Science. University of Florida Extension. Personal Interview.
Main Photo Credit: Paul Maguire | Adobe Stock
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