Cool-season grasses should be mowed to a height of 2.5 inches before winter. Warm-season grasses in the Bermuda grass family (Bermuda Grass, Centipede, and Zoysia) should be mowed to 1.5 inches before winter.
If you live in a region that receives snow, plan to mow your grass to 2.5 inches once daytime temperatures dip below 50℉. Cool season grass growth stops at this temperature, so perform a final mowing run at this time. Usually, the best time for a final fall mow is late-October through early-November.
Warm-season grasses stop growing when temperatures go below 60℉, so plan to mow your warm-season grass at this time. Depending on your region, you may perform a final fall mowing run anywhere from early-October to early-December.
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What’s the Best Grass Height for Winter?
For most grasses, 2.5 inches is the ideal winter height. This preserves enough of the grass blade that your lawn will make a strong return in spring. If your grass is cut too short for winter, it may die or struggle to green up in the summer months. If your grass is too long in winter, it is subject to disease and pest infestation. To keep your lawn healthy, it’s crucial to mow before winter sets in.
Best Winter Grass Height: Cool-Season Grasses
Cool-season grasses do best when mowed at 2.5 inches in height before winter sets in. Any shorter, and your grass can be severely damaged or even killed. A short mowing in fall will cause your grass to struggle in spring, providing an opportunity for weeds to invade. Mow at 2.5 inches for the following grass types:
- Rye Grass
- Fescue Grass
- Kentucky Bluegrass
These grasses thrive at relatively long blade heights. By mowing them long as temperatures cool, you ensure the grass continues to photosynthesize and store energy for future growth.
Best Winter Grass Height: Warm-Season Grasses
Warm-season grasses come in several different varieties and have unique needs. Creeping grasses in the Bermuda Grass family should be mowed at 1.5 inches. Meanwhile, St. Augustine Grass and Buffalo Grass survive winter best with a cutting height of 2.5 inches.
Mow at 2.5 Inches:
- St. Augustine Grass
- Buffalo Grass
Mow at 1.5 Inches:
- Bermuda Grass
- Centipede Grass
- Zoysia Grass
By tailoring your pre-winter lawn maintenance to your warm-season grass species, you prepare your lawn for the winter months much more effectively. This leads to a better spring green-up.
Mowing Before Winter: The One-Third Rule
Do not mow more than one third of the grass blade length during the final mow of the fall. This will put a large amount of stress on the grass plant, potentially causing serious damage that is difficult for the grass to recover from as it moves into dormancy.
- Mowing to 2.5 inches: If grass is greater than 4 inches tall, mow in stages.
- Mowing to 1.5 inches: If grass is greater than 2.5 inches tall, mow in stages.
If mowing to the optimal height for winter grass would require you to violate the one-third rule, mow in multiple stages. Set your lawn mower blade height to higher than usual and perform an initial mowing run. Then, wait 3–5 days for grass to recover and mow a second time, trimming grass to the ideal winter height.
Should You Mow Your Lawn in Winter?
Do not mow your yard during winter. Although you may want to cut grass when it’s cold outside, refrain from doing so. Mowing frozen or frosted grass can cause severe damage to grass, killing it.
Even if temperatures are above freezing and your grass is not frozen, do not mow dormant grass. Cutting a grass blade essentially leaves an open wound. Growing grass recovers quickly from mowing, but dormant grass cannot heal. Mowing in cold weather increases the chances of grass disease.
When Should You Mow for the Last Time in Fall?
Mow for the last time in fall when temperatures reach a point where your grass has stopped growing. The ideal daytime temperatures for mowing grass varieties are:
- Cool-Season Grasses: 50℉
- Warm-Season Grasses: 60℉
- Final mowing is typically performed in late-October through early-November
As the winter season approaches, grass plants slow their growth until it stops almost completely. By cutting grass before winter, you will trim your grass to the ideal height for green-up in spring.
What Happens if Grass Isn’t Mowed Before Winter?
If you don’t follow a proper lawn care regimen and mow before the winter months arrive, it can have a negative impact on your lawn. The following are caused by leaving grass too long in winter:
- Snow mold
- Rodent infestation
- Grass rot and fungus
- Thin grass and poor spring green-up
In order to avoid winter season damage to your lawn, mow your grass to the proper height before cold weather sets in. You’ll keep out rodents who burrow into tall grass and make homes beneath snow cover, as well as prevent disease that can kill your lawn down to the grass roots.
Best Fall and Winter Grass Care Practices
In addition to mowing your grass before the winter winds bring snow and cold weather, there are several other lawn care practices to perform in fall to prepare your lawn for the winter months.
- Aerate your yard
- Apply organic fertilizer to your grass
- Mulch fallen leaves, or rake and remove them
By feeding your lawn, aerating to allow water and nutrients to enter the soil, and getting rid of leaves that can smother grass, you set yourself up for a beautiful lawn when warm temperatures arrive. By taking these measures, in addition to mowing before winter, your lawn will turn green faster and choke out spring weeds.
Best Height for Winter Grass
The rule of thumb for pre-winter lawn care is to cut grass to 2.5 inches tall. While this rule works well for most grass varieties, creeping grasses, such as Bermuda Grass, Centipede Grass, and Zoysia Grass survive winter best when mowed to 1.5 inches.
Mow your lawn as temperatures drop low enough for your grass to enter dormancy (50℉ for cool-season grasses and 60℉ for warm-season grasses). Refrain from mowing your lawn in winter. Never mow frozen grass, dormant grass, or grass that is under snow cover.
A good, simple mowing pass will cut your grass to the ideal height for a spring return, mulch fallen leaves, and cast fertilizing grass clippings onto the soil, where they can decompose and feed your yard. Mowing before winter sets in is an essential step to prevent snow mold and other plant diseases.