How to Know When It's Time to Stop Mowing Your Lawn for the Year

While there are a handful of people who love the act of getting outdoors and mowing their lawn during the growing season, there are probably even more people who are counting down the days until they can pack up their lawn equipment and put the bulk of their outdoor chores behind them.

Exactly when each person gets to call it quits for the year depends on a few different factors. We spoke to two landscaping pros to find out when it’s safe to do that final mow and ensure you’re not jumping the gun by stopping too soon.

When to Stop Mowing Your Lawn

As fall approaches, it’s time to start thinking about preparing your lawn for the winter months ahead. "Deciding when to stop mowing your lawn is largely determined by the region you live in, and the grass types that you have," says Jason McCausland, technical coordinator at Weed Man. "Many recommendations are to stop mowing after the first frost, which is a reasonable guideline, but with our ever-changing climate it is possible to still have growth after an early season frost."

According to McCausland, the true answer lies in an easy to remember rhyme. "The golden rule is to keep mowing if it’s still growing, and of course, never remove more than a third of the grass blade at each mowing," he says.

Signs It’s Almost Time for the Last Cut

You’ll likely notice a few signs that your growing season is coming to an end before it actually happens. This can be a tricky time because while your lawn has stopped growing, it will still be green. 

Dropping Temperatures

The timing is best determined by temperatures. according to Roger May, director of technical operations at TruGreen. Daytime temps should consistently be in the 50s and overnight temperatures down into the 40s, so that you can be sure that your turf has gone dormant. 

"Keep an eye on the weather, because a week of 60-degree temperatures can cause the lawn to start growing again, and you may need to make an additional mow before it gets cold again," says May.

Falling Leaves

May says one of the best indicators that your last mow is approaching is when all of the leaves are off the maple trees. Not only is this a sign that the seasons have fully switched over, but it can also help on your general lawn maintenance since you won’t have to bring out your mower to mulch anymore leaves.

The First Frost

You can also expect to be done about four to five weeks after your region experiences its first frost. "By that time, daytime and nighttime temperatures should be consistently cold enough that the lawn will no longer grow," May says.

How to Handle That Last Mow

You’ll have to make a few tweaks during the final mow of the season, according to May, who says that you’ll need to first know what type of grass you’re dealing with—specifically warm-season or cool-season grasses—before determining what changes you’ll make. 

"On average, your grass height for winter should be around 2 inches, depending on grass type," he says. "Due to the cold winter temperatures, grass that is too short might go into shock and grass that is kept too long can be at greater risk of developing snow mold." Generally speaking, that will mean lowering your mowing deck one or two notches. "This will help reduce snow mold in late winter and speed up spring green," he says.

Cool-Season vs. Warm-Season Grass

When to Stop Mowing Cool-Season Grass

According to McCausland, most cool-season turfgrasses start to slow leaf growth once daytime air temps stay below 50 to 55 degrees. "During your last few cuttings of the season, drop the height gradually (no more than one-third of the blade) to around 2 inches as a rule of thumb," he says, adding that there can be a few variables that can have an effect on this strategy. "If your region is prone to significant snowfall, you may choose to mow closer to 1 1/2 inches in order to reduce the likelihood of damage caused by snow molds or rodent problems such as voles and moles."

As for the northern and cooler regions of the United States, where temperatures drop significantly in the winter, McCausland says cool-season grasses like Kentucky bluegrass, fescue, and ryegrass commonly go dormant. "These grasses often turn brown or straw-colored during the winter months when temperatures are consistently low," he says.

When to Stop Mowing Warm-Season Grass

The timing for your warm-season turfgrass lawn will depend on your location and on the specific type of warm-season grass you’re working with, according to McCausland, who says knowing this can help you determine the best time to stop mowing. 

"This usually occurs when the average daytime temperatures consistently drop below 50 to 55 degrees, similar to other grass species," he continues. "In most cases, warm-season grasses will go into some stage of winter dormancy and will need little to no mowing."

When you do need to mow these types of grasses, McCausland says your mowing height should be slightly lower than normal but not too close to the ground. "This will help prevent disease and provide some protection during the winter months, but avoid scalping your lawn, as this can damage the grass," he says.

Maintaining Your Grass After the Last Cut

You should ensure your lawn has enough nutrients to store before the ground gets too cold; this can help prepare your lawn for the winter season and provide a jump start for the spring. "Cool-season lawns will benefit from additional nitrogen, and warm-season lawns will benefit from potash," May says. 

Of course, once you're done for the year, it’s also the perfect time to make sure you’re giving your mower a little extra TLC after a busy mowing season. "Sharpen your mower blade," May says. "A sharp blade will help mulch grass clippings and any fallen leaves into the lawn and provide additional nutrients and organic matter to the lawn." 

As an added bonus, he also says that a sharp blade will help your machine work more efficiently when you lower the mowing deck—making life that much easier for you the next time you need to pull out your lawn mower.