Gardeners have a long-standing debate about whether to mow or let the lawn grow tall in late fall in the Midwest. If you want a healthy, early-greening lawn in the spring, researchers agree that mowing as long as grass is actively growing is the best bet. However, low-maintenance gardeners who wish to skip the chore will still have grass in the spring.

Reasons to mow

Cool-season grasses are susceptible to diseases such as snow mold over the winter. Tall grass creates a more favorable environment to disease development than short grass, and the result can be dead spots in the lawn when spring arrives. Tall grass is more favorable because it is more likely to become matted from winter precipitation. Then, when a few sunny, somewhat warmer days arrive, moisture is trapped around the base of the plant.

Mowing can also help with leaf litter. Dense leaf litter over a lawn shades out the turf underneath, so leaves should be chopped or removed to keep the lawn healthy. Large thin leaves will chop fairly easily with a normal lawn mower blade. A mulching blade gives the mower some added oomph. Small or very dense leaves tend to clump and may need to be raked from the lawn or removed with a bagger on the mower. Raking is also easier on short grass than long grass.

Reasons to skip mowing

An old wives’ tale is that the taller blades of grass help insulate the plants’ roots and provide winter protection. Since the cool-season grasses commonly grown here are hardy much farther north, this argument is really a moot point. For warm-season grasses like zoysia grass or fine turf-type Bermuda grass that are less winter hardy, the plants might indeed provide a little insulation. Warm-season grasses are brown by now, though, and probably had their last mow earlier in the season.

Another theory is that the grass will be healthier going into winter, since mowing in general stresses turf. While it’s true that mowing is a stressor to the plant, the best way to reduce that stress is to remove less of the leaf blade at one time. That means mowing more often, ideally removing a half inch or less of the grass blades in each mowing. (In October and early November, that may mean more mowing than usual). Letting the grass grow tall might make it healthier in the short term, but eventually it needs to be mowed again.

The good news is that even without a scientific reason to skip the mowing, doing so really has little repercussion. You might even get to spend the time doing something more fun.

— Jennifer Smith is a former horticulture extension agent for K-State Research and Extension and horticulturist for Lawrence Parks and Recreation. She is the host of “The Garden Show.”