When to stop mowing the lawn: 4 signs

Garden and lawn care typically slows down as the weather cools. In midsummer, the plants and the grass grow and thrive and need to be mowed frequently. People looking to take a break from lawn care will be happy when temperatures drop, which usually means a break from outdoor chores. However, when you can turn off your lawn equipment and store it depends on several factors, including geographic region, climate, and grass type.

We spoke to three lawn experts about when to stop mowing the lawn, the signs, when the final cut is approaching and why mowing in cold temperatures can harm your lawn.

When to stop mowing the lawn

As the weather cools, plants and grasses slow their growth cycle. The type of grass and where you live affect grass growth in cooler weather. “The climate or region you live in can have a big impact on when you stop mowing,” says Erin Harlow, Horticulture Extension Agent III, University of Florida/IFAS Extension Columbia County. During the colder months, mowing tends to take a back seat as some grass species go dormant while others slow growth. “Many of our grasses in lawns grow dependent on soil temperature, not necessarily air temperature,” she says. “If the temperature stays warmer for longer, the plants will continue to grow and may need maintenance.” There is usually one last trim or mow of the season before temperatures drop and it is too cold to mow.

Cool or warm season grass

There are two types of grasses: the cool-season grasses and the warm-season grasses. Geographic location influences whether you grow cool-season or warm-season turf varieties. Warm-season grass grows in warm to hot climates and often stops growing in cold temperatures. “In Texas, a lack of rainfall can cause turfgrass species to go dormant, as can cold, freezing weather,” says Elizabeth McMahon, Gillespie County AgriLife Extension Horticulture Agent.

“Warm-season lawn grasses generally go dormant during the winter months,” says Harlow. “If they are in zones 9B-11, they may not go dormant at all.”

Cool-season grass can continue to grow in cooler weather. “Cool-season lawn grass may need to be maintained for a longer period of time as it continues to grow and stay green during the winter months,” says Harlow. “Of course that depends on the weather conditions.”

Geographical region and final cut of the season

Geographical location is a key factor when preparing for the final cut of the season. “The climate and region determine what types of lawns you grow, and different warm-season lawn grasses have different dormancy periods,” explains McMahon.

If you are in a warmer region, you may not get much of a break from trimming the grass compared to colder geographical areas. “In southern regions or areas with mild winters, such as Florida, Texas or parts of California, it is the warm season [grass] Varieties like Bermuda or St. Augustine may grow longer into the fall and even winter,” says Valerie Smith, content strategist for Sod Solutions. As long as the grass continues to grow, mowing must continue. “Mowing may not need to stop completely, but the frequency will decrease as temperatures cool and growth slows,” she says.

In colder weather, plants slow or stop growing. “In cooler northern regions or areas with harsh winters, such as the Midwest or Northeast, grass growth stops earlier in the fall,” Smith says. “Cool-season grasses such as fescue or Kentucky bluegrass, which are common in these regions, also slow down as temperatures drop.” When the grass stops growing, usually after the first frost, mowing should stop, she says.

What you should know for the final cut

When preparing for the final cut of the season, the type of grass will affect the height at which the grass needs to be cut. “Mowing below the recommended height can damage the plant and cause severe damage and stress,” says Harlow. When making the final cut, care must be taken not to leave the cut too short or too high. “It is not recommended to let the lawn grow taller than the recommended height as it can shade itself and become thin and brown underneath,” says Harlow. The best way to ensure the grass is cut and stays at the correct height is to know the type of grass and cut it within the recommended mowing height.

How tall for warm season grass?

Lawns for the warm season, such as: Plants, such as St. Augustine, should be cut between 2.5 and 4 inches, says Harlow. Smith recommends cutting warm-season varieties, including Bermuda, St. Augustine and Zoysia, a half-inch higher than usual during the final cut. “Leaving the grass a little taller protects the base of the blades and runners from frost, creating a barrier that protects the growing areas from cold damage,” she says. Avoid cutting too short, as this leaves the grass vulnerable to cold and frost and potentially damages the lawn, she adds.

How tall for cool season grass?

“For cool-season grasses like fescue or Kentucky bluegrass, the grass should be cut about a half-inch shorter than normal for the final mow,” says Smith. This helps the grass cope with colder temperatures and prevents matting, which can lead to snow mold, she adds.

Signs that the final mowing is approaching

Several clues signal that it is time for the last mowing before winter:

Check the soil temperature

A practical way to know when the final cut is coming is to check the soil temperature. “For cool-season grasses, growth generally stops when the soil temperature drops below 4°C (40°F),” says Smith.

Cooler temperatures

The weather is a good indicator that the season is changing. “Grass growth typically slows significantly as temperatures drop,” Smith says. This happens to cool-season grasses when temperatures drop. “If you notice that your grass is no longer growing quickly, it may be time for one final mow,” she says.

Falling leaves

As the weather cools, the leaves begin to fall. A visual clue is if there are plenty of leaves on your lawn. “It often signals that your lawn is entering the dormant phase,” says Smith.

Know when the first frost will come

The final cut should be done before the first frost. The weather changes, so you may not be able to rely on your calendar but instead have to pay attention to frost forecasts. “It is advisable to mow at least a week before the first hard frost in your area,” says Smith. “This ensures the grass is at an optimal height for winter hardiness.”

Why you don't want to mow in cold temperatures

When the weather turns cold, most plants slow their growth or stop growing altogether until the weather warms up again. When it's cold outside, you'll probably want to stay cozy inside rather than rev up the lawnmower. The lawn also wants to be left alone. “Mowing in temperatures below 4°C can put a lot of stress on the grass,” says Smith. “At these temperatures, grass growth slows significantly and its ability to recover from mowing is compromised.” This can cause grass to be more susceptible to disease.

Blades of grass are more sensitive and brittle in cold weather. “Mowing in these conditions can cause the blades to tear or tear, leaving an unsightly lawn and increasing susceptibility to pathogens,” says Smith.

Avoid mowing wet or frozen grass

Mowing when the lawn is frozen or wet can damage the grass. Once temperatures drop, leave the lawn alone. “Mowing on frozen or excessively wet ground can cause compaction, which limits air, water and nutrient transport to the roots,” says Smith. “This compaction puts stress on the grass and affects its growth potential when it springs back up again in the spring.” Mowing when wet, whether from rain, dew or frost, can also result in uneven cuts, which can weaken the lawn and make it more susceptible to disease, she says.

As a rule of thumb: only mow the lawn when it is dry. The temperature is also important before you get the mower out. “Wait until temperatures are at least 40 degrees Fahrenheit before mowing,” says Smith.