| Key Takeaways |
|---|
| • Warm-season grasses stop growing once air temps drop into the 50s°F; cool-season grasses stop growing once air temps climb into the 80s–90s°F. • Soil temperature is a better guide than air temperature because roots and crowns respond to conditions at the soil surface and just below it. • Dormant grass often turns brown even though the crowns and roots can remain alive until growing conditions improve. |
When does grass stop growing depends primarily on two things: what type of grass you have, and how cold or hot it gets where you live.
Warm-season grasses go dormant once temperatures drop into the 50s°F, while cool-season grasses shut down growth once temperatures climb into the 80s°F and 90s°F. Either way, the grass isn’t dying, it’s entering dormancy to protect itself.
If you want a professional set of eyes on your lawn before it goes dormant, a local lawn care pro can check for anything else going on before the cold or heat sets in.
What temperature makes grass stop growing
Grass stops growing once it crosses a temperature threshold specific to its species, generally below 50–55°F for warm-season grasses and above 80–90°F for cool-season grasses, measured as air temperature. That’s the easiest number to check, but it’s not the real trigger.
Soil temperature matters more than air temperature. Grass roots and growing points sit at or just below the surface, so soil temperature is what actually controls dormancy, while air temperature is only a proxy.
Soil temperatures usually change more gradually than day-to-day air temperature, so a brief warm spell or cold snap does not always change turf growth right away.
Tammy Sons, founder and CEO of Tennessee Wholesale Nursery in Altamont, Tennessee, says it’s best to track it with an inexpensive soil thermometer.
She recommends taking readings “at 2 to 4 inches down into the root zone in the same place at the same time of day for a few days.” Sons says that this consistency is important “because it is the trend over time that matters.”
Warm-season grasses generally lose color and go dormant when average air or soil temperatures drop below about 50°F to 55°F.
Cool-season grasses resume active growth once soil temperatures reach around 50°F and slow down once air temperatures climb past 90°F in summer. Root growth declines sharply above 80°F soil temperatures.
While checking air temperature is the fastest way to gut-check your lawn, Mary Helen O’Leary, president and owner at Heroes Lawn Care in Omaha, Nebraska, says you don’t have to overthink or measure the soil directly.
“You don’t need a thermometer,” O’Leary says. “You just need to observe signs like hostas are laying on the ground, or when the grass tips stay perfect for 10 days.”
Warm-season grasses
If you live in the bottom half of the U.S., you probably have warm-season grasses. These species generally go dormant when the average air temperature drops below around 50°F.
While warm-season grasses handle heat well, most species begin slowing once temperatures consistently exceed the mid-90s°F to low 100s°F.
Here’s a temperature breakdown for the most common warm-season grasses:
| Grass type | Stops growing below | Stops growing above |
| Bahiagrass | 58° | 102° |
| Bermudagrass | 41° | 100° |
| Buffalograss | 52° | 100° |
| Carpetgrass | 50° | 95° |
| Centipedegrass | 50° | 100° |
| St. Augustinegrass | 50° | 100° |
| Zoysiagrass | 50° | 93° |
Note: These upper temperatures are estimates, not strict limits. Warm-season grasses can keep growing in extreme heat if they get enough water.
Cool-season grasses
If you live in the top half of the U.S., you likely have cool-season grasses. These grass varieties grow most vigorously between 60°F and 75°F, and growth slows once temperatures climb above 75°F. Most species don’t fully stop growing until temperatures reach the mid-to-high 80s°F or 90s°F.
Though they can survive colder temperatures, cool-season grasses typically stop growing once temperatures fall into the low 30s°F.
Here’s a chart showing what temperatures each common cool-season grass stops growing at:
| Grass type | Stops growing below | Stops growing above |
| Fine fescue | 37° | 86° |
| Kentucky bluegrass | 32° | 90° |
| Perennial ryegrass | 32° | 86° |
| Tall fescue | 32° | 95° |
When grass stops growing by region and month
The U.S. has such a varied climate that there’s no universal start and stop date for grass growth. However, we can provide some general dates based on regions of the U.S.
| Region of the U.S. | Warm-season grass | Cool-season grass |
| Northeast | October through May | November through April and July through August |
| Southeast | November through March | January through February and July through August* |
| Midwest | October through April | November through March and July through August* |
| Northwest | November through May | November through February and July through September* |
| Southwest | November through February | June through August* |
*If not irrigated properly (more on that in the next section).
How water affects grass growth
Even when temperatures aren’t extreme, a lack of water can push grass into dormancy early. Dormancy is a lawn’s survival mode. It stops growing to conserve resources and endure drought.
If you notice thinning, a dull blue-gray color, or footprints that don’t spring back, check our list of 8 signs your lawn is drought-stressed.
“If it does go dormant and turn brown, don’t waste water by drowning it with a heavy soaking,” says Taylor Olberding, founder and co-owner of Heroes Lawn Care.
“Just give it a light sip of about a quarter-inch of water every few weeks,” Olberding says. This is “just to keep the base of the plant alive without tricking the lawn into waking up too early and wasting its stored energy.”
If you’ve been watering consistently and your grass still won’t green up, our guide on How to Help Your Lawn Recover from Drought covers what to try next.
Other reasons your grass stops growing
Temperature, time of year, and water are the main reasons your grass stops growing. Here are some other factors that could cause your grass to stop growing:
- Disease, weed, or pest infestation: Your grass can’t put its energy into growth if it’s fighting these threats.
- Nutrient deficiency: Nitrogen, phosphorus, and potassium are crucial for grass growth. Get a soil test to see if your grass is missing these necessary nutrients.
- Improper mowing: If you cut your grass too short, you may stunt its growth. Mow at the proper height for your grass.
- Soil compaction: Your grass may struggle to grow if the soil is compacted due to excessive foot traffic or too much water.
- Unbalanced pH: If your soil is too acidic or alkaline, your grass will struggle. You can change soil pH with amendments.
- Lack of sun: Grass needs photosynthesis to grow, and your yard may not provide enough sunlight. To solve this problem, you can cut back plants to reduce shade or switch to a shade-resistant grass type.
FAQs
According to Turfax, the lethal threshold for grasses is based on tissue temperature rather than air temperature. Even if the air is hotter or colder than the temperatures below, your grass could survive if it’s well insulated.
Warm-season grasses die when tissue temperatures rise above 110°F to 120°F or fall below 31°F to 20°F.
Cool-season grasses die when tissue temperatures rise above 104°F and 112°F or fall below 26°F to -20°F.
According to the University of Missouri Extension, warm-season grass grows the most in summer when temperatures are between 80°F and 95°F. Cool-season grass grows best in spring and fall when temperatures are between 60°F and 75°F.
People often call any brown or yellow grass dead, but there is a difference.
“When the grass begins to brown, I use a simple ‘pull test’, a gentle tug on a handful of grass,” Sons says.
“Dormant grass will have a firmly attached living crown that will have some firmness at or just above the soil surface,” Sons explains.
“Dead grass easily pulls away and has a soft rotting crown and roots,” she adds. Dead grass won’t recover, even after things return to normal.
When your lawn isn’t growing, it needs little attention. You also need to be more careful with it. You should hold off on fertilizer, since dormant grass can’t absorb it, and wait to aerate or overseed until growth resumes.
“Mowing is pointless if growth has ceased throughout the season,” Sons says. “Frequent traffic and pointless scalping can injure crowns, compact the wet or frozen soil and fray those areas that aren’t yet replacing their lost leaf tissue.”
“My rule is to let the grass determine the ultimate mowing, not some day on the calendar,” she advises.
Want grass to grow? Call a pro
Grass growth is a complex equation based on temperature, water availability, and growing conditions. If you’d rather not track its growth, hire a professional to do it for you.
Lawn Love can connect you with local lawn care pros who know all about grass growth, dormancy, and lawn treatment schedules.
- Main Image: A ground-level view captures a lush, freshly cut green lawn on a sunny day. Photo Credit: New Africa / Adobe Stock
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