If your grass is too long, it's at risk for disease. The ideal grass height for winter is between 2 inches and 2.5 inches. This keeps grass short enough to resist disease spread, but not so short that it becomes overly stressed by cold temperatures.
Cut your lawn to possibly the shortest height you have all season. The ideal height is around 2 1/2 inches. Cut it too low and the grass might not be long enough to photosynthesize and provide nutrients to the roots. Too high and the frost might become matted after a snowfall.
According to experts, you should stop mowing your lawn once grass enters dormancy and temperatures drop below 50˚F. For most regions, this will usually be late October or during November. However, if your garden is usually wet (and not frosty), you could mow up until late November.
Focus on striking the right balance in fall so your lawn's ready for winter. Shorten your cool season grass to about 2.5 inches before the first frost in winter. Mow warm-season grasses to 1.5 or 2 inches in fall.
With summer's heat and dryness at an end, September is the best month to lay the groundwork for next year's lush lawn. Pre-winter lawn care consists of aerating the turf—to reduce compaction and make it easier for fertilizer and water to reach the roots—and reinvigorating thin areas with compost and seed.
100%, you certainly should cut your grass before winter. But like any good hair trim, you should not cut short all at once. Best practice teaches us that you should progressively lower your grass height, instead of giving it one big chop.
In general, you should cut your grass after it has become dormant but before the frost.
When the weather is more akin to summer (in September and early October), you'll want to mow around every 6 days. However, as the temperature starts to drop consistently, your frequency will, too. Eventually you'll be mowing every 8 or 9 days before stopping entirely and breaking out the snow blower for winter.
Areas where grass blades were cut too short will usually recover slowly, but the brown patches may be evidence that you cut into the crown (growing point) of some grass plants and killed them. If the dead patches are no more than a few inches in diameter, grass regrowth may fill in the bare spots.
Know Your Grass
Cool-season grasses such as fescue, rye, or even bluegrass do not necessarily go completely dormant during the winter months. It's a good idea to water them every now and then on a mild day when there is no threat of a hard freeze overnight.
Dull blades tear and bruise the leaf tips. Dormant lawns (those that have turned brown) should not be mowed. Pedestrian and mower traffic could damage the turf. Gardeners have two basic options on lawn care when confronted with hot, dry weather.
Taller grass also shades the ground, slowing weed growth and water loss from the soil. The ideal length of your lawn depends on your climate, but most experts agree you should keep your grass between 2 1/2 inches to three inches long, with the last cut of the season remaining the same.
Waiting to mow protects insects
These insects feed animals such as birds and frogs and allow them to thrive. Leaving our lawns alone in the early spring allows these insects the time to wake up, multiply after the winter, and contribute to the part they play in the ecosystem.
A longer grass blade will shade the ground underneath, keeping it cooler, meaning it won't dry our as quickly as when the lawn is mowed short. In other words, the lawn does not have to receive as much supplemental water. Reduces weed growth.
“Keeping grass a little longer in the heat of summer helps,” explains Williams. “The roots extend deeper into the earth, keeping weeds from coming up and competing for water. And because the turf is denser, it requires less water.” Williams recommends a blade height of about 4 inches during the summer months.
Finally, mulch prevents weeds from growing. If you don't enjoy the back-breaking work of weeding, come spring, adding mulch in the fall / early winter will save you a lot of effort! Mulch in most (but not all) formats will break down over time, which goes some way to enrich your soil.
Mowing actually helps make your grass grow thicker because the tip of each blade contains hormones that suppress horizontal growth. When you cut the lawn, you remove these tips allowing the grass to spread and grow thicker near the roots.
Grass Goes to Seed
In periods of stress such as unusually hot weather or being allowed to grow too long, grass can go to seed. This results in the grass looking more like a weed with its small white flowery stems.
Most turf grasses can grow up to 4–24 inches tall. An overgrown lawn is more susceptible to pests, weeds, and diseases. If you don't mow your lawn, it may be difficult to mow it in the future. You can only cut one-third of the height of your overgrown grass at a time.
No Mow May was first popularized by Plantlife, an organization based in the United Kingdom, but is now gaining traction across North America. The goal of No Mow May is to pause mowing during the month of May, allowing flowers to bloom in your lawn to help early season pollinators.
Generally, the cutoff point comes when temperatures drop below 50°F during the day. Usually, that's late October or early November, but some warm areas may push that date back to the beginning of December.
However, most professional gardeners would agree that between 8 AM and 10 AM is the best time of day to cut your grass. The reason for that is that lawns need time to heal before evening. Grass needs the benefit of the day to dry and heal before dusk settles.
If temperatures are below 50 degrees Fahrenheit, then you can generally assume the grass is dormant. That usually happens around October or November, but can be December depending on where you live. When Should You Stop Cutting the Grass? The first frost of the year is normally a good indicator of when to stop mowing.
It's best to wait for wet grass to dry before mowing. Wet grass clippings can clog your mower, causing it to choke and spit out clumps of wet grass that could smother and kill your lawn if left unraked. It's best to wait for wet grass to dry before mowing.
If you know a heavy rain is coming, then try to mow your lawn before the storm hits. Planning this way will save you the trouble of waiting a day or so for the grass to dry for your next mowing. For most other days, try to pick either the mid-morning or late afternoon to mow.