When Can I Quit Mowing the Grass in the Fall?

Temperature Dictates

• Cool- and warm-season lawns will stop growing when daytime air temperatures dip below 50 degrees Fahrenheit for a week, according to Cornell University. For those in southern parts of the United States, you may quit mowing in late fall, while gardeners in northern regions may stop mowing at the end of summer to early fall. Keep an eye on your weather forecast and examine the lawn for growth.

Last Mowing

• Mow your lawn one last time in the fall when it reaches 4 1/2 inches in height, as suggested by Cornell University. Leaving your grass over 4 inches tall raises the risk of it becoming matted and contracting a fungal disease during the winter. Snow mold is a common fungal disease that occurs on lawns left long at the end of the season. This fungal disease kills small to large areas of grass.

How Short to Mow

• Gardeners should keep their lawn 3 inches in height for healthy root systems and to prevent fungal disease. Never mow more than a third of the blade's length at one time, or you can encourage weak root systems. When grass is mowed too short, roots are unable to produce dense growth. The result is thinning grass or bare areas where weeds can easily germinate and grow. In the fall, mow your lawn down to 3 inches to end the season on a healthy note.

Clippings

• Leave the grass clippings--no clumps--on your lawn after mowing in the fall to contribute extra nitrogen. Even though your grass blades may stop growing, grass roots still grow and spread during much of the fall and winter. It is beneficial to distribute a thin layer of grass clippings over the lawn.