Mowing Heights by Season and Grass Type

If you have a lawn, chances are good you also have a lawn mower that you break out whenever the grass starts getting a bit too long. However, for a healthy lawn, you don’t want to wait until the last minute to mow. All turf has an ideal grass height—and letting your grass grow too long (or keeping it too short) can have an impact on the overall health of your lawn. But the best height to cut grass depends on a few factors, including the type of grass you have and the season. Ahead, we’ll break it all down — and arm you with tried-and-true grass cutting tips to help keep your lawn in great shape throughout the seasons.

Everything requires balance, including your lawn. Cutting your grass too short (in other words, scalping) stresses your turf and can result in poor growth, bare spots, or visible damage. Scalped lawns may also be more vulnerable to weeds — many of which require specialized care to get under control. But letting your grass grow freely isn’t ideal either. Aside from looking unkempt, excessively long grass may be more attractive to pests, and can lead to a decline in the overall health and thickness of your lawn. As we said, it’s a balancing act.

What height to cut grass for optimal health varies depending on the type of grass and when it grows. 

Cool Season Grasses

Cool-season grasses are those that experience active growth during the spring and fall, when temperatures range between 60^o and 75^o F. These grasses can be found throughout the Northeast, Midwest and the Northwest, as well as parts of the Transition Zone (an area in which both cool and warm-season grasses can be found). The grass cutting height chart below details the ideal mowing heights for some common cool-season grasses. 

Warm Season Grasses

Warm-season grasses are those that grow during the summer months and go dormant when the average soil temperature dips below 55^oF. These grasses are prevalent throughout the Southern United States, as well as some parts of the Transition Zone. The ideal mowing heights for common warm-season turfgrasses can be found below.

To cut your grass to a specific height, adjust your lawn mower height settings in accordance with the above guidelines. Keep in mind, however, that you never want to cut more than ⅓ of the grass blade off at a time, as doing so can stress your lawn and result in yellowing or scalping damage to your grass. If mowing tall grass, more than one session may be required to get your lawn to the optimal height.

Seasonality also plays a significant role in how and when you should mow your lawn. The reason for this is simple: Different weather conditions have different effects on your lawn. For more details on how short to cut grass in different seasons, keep reading. 

Grass Height for Winter

Both cool and warm-season grasses typically go dormant in the winter. Effectively, this means the grass stops growing until soil temperatures rise—so mowing generally isn’t necessary in the winter. However, you want to take precautions in the fall to prepare your lawn for a potentially cold, snowy winter. One thing that you can do is mow your lawn to approximately two inches before the first frost of the year. At this height, roots and crowns are protected from the harsh, cold weather, but still short enough to help protect against snow mold. If you need help or advice on how best to protect your lawn during the winter, contact your local TruGreen® lawn care expert. 

Grass Height for Spring

For the first mow of the season, you’ll want to mow slightly shorter (roughly ½ inch) than the recommended growing-season height to help remove dormant grass and  encourage green-up. As for when to conduct the first mow of the season, it depends. Cool-season grasses can be mowed after any snow cover melts—usually early spring—while warm-season grasses should be mowed for the first time once the grass starts growing again (usually by late March, depending on the region).

Grass Height for Summer

Freshly-cut grass is a quintessential summer smell — and that’s because many lawns require more maintenance in the summer. Warm-season grasses, in particular, experience more rapid growth during the summer months. The charts we included above should help you determine how short to cut your grass during the dog days of summer. For optimal health, aim to cut your grass on the higher side of the range. Longer grass helps keep your soil cool, reducing the need for watering and cutting down on the maintenance needed to keep it in great shape. Mowing on the high side can also promote healthier roots and minimize weed development. Keep in mind that you want to avoid mowing during periods of extreme heat or drought, as doing so can stress your lawn.

Grass Height for  Fall

In the fall, aim to keep your lawn at or near its ideal mowing height, as outlined above. If you have a cool-season lawn, fall may bring with it more frequent mowing, as these grass types grow in cooler temperatures. 

Once temperatures start to dip (but before the first frost), you’ll want to do your last mow of the season, cutting to a height of approximately two inches to protect your turf for winter.

In addition to mowing to the proper height, there are several things you can do to avoid stressing your lawn when you cut the grass. Follow these tips to help promote a healthy, thriving lawn: 

• Ensure your mower’s blades are sharp. Dull blades can shred the grass blade, leaving the grass weak and vulnerable to disease.
• Avoid mowing during periods of extreme heat or drought.
• Change direction each time you mow to help prevent soil compaction or damage from your mower’s wheels.
• Leave grass clippings on your lawn to help give your lawn extra nutrients.

For more help cultivating - and maintaining — a healthy, vigorous lawn, contact your local TruGreen lawn care professional.