Most gardeners would agree that maintaining a good-looking lawn takes a lot of time and effort, especially in terms of proper mowing. In order to discourage weeds, resist insects and diseases and remain attractive, lawns need to be mowed at the correct height and frequency. There is no single height or frequency that fits all turfgrasses, so you need to know something about the kind of grass you’re growing to do the best job.

Cool season grasses, such as Kentucky bluegrass, tall fescue and perennial ryegrass, grow best in areas that have moderate summer temperatures and cool or cold winter temperatures. With good care, these grasses can also grow in our area, where summer temperatures are high. One way to ensure success is to raise the mowing height approximately 1/2 inch from mid-May through September to prevent heat damage. Cool season grasses should be mowed at 2 inches during the hot season and 1-1/2 inches high the rest of the year.

Warm season grasses, such as Bermudagrass and St. Augustinegrass, also grow well in our area and are most vigorous from late spring through early autumn. Their growth is slowed by low daily temperatures or cool nights, and they are dormant during the cold winter months. The most popular warm season grass, common Bermudagrass, should be mowed at 1 inch high. The hybrid Bermudagrasses should be mowed at 1/2 to 3/4 inch high. St. Augustinegrass, which is less popular, should be mowed at 3/4 inch high.

Proper mowing height is important for several reasons. If mown too low, grasses may produce a bleached, shallow rooted, weak turf that is susceptible to weed and disease invasion. On the other hand, mowing too high results in excessive thatch accumulation, especially with the warm season grasses.

You should be able to tell when and how often to mow your lawn by how fast it’s growing and by the appearance you desire. Mow cool season grasses more frequently in spring and autumn and warm season grasses more frequently in summer. In general, mow often enough so that 1/3 to 1/2 of the grass height is removed at any one time. For example, if you maintain a tall fescue lawn at 1-1/2 inches, mow it when the grass reaches 2 to 2-1/4 inches high. This may mean mowing tall fescue every four or five days during the spring months and only once a week during the summer. This is especially so if you are fertilizing your lawn heavily during early spring. If you are not removing the grass clippings from the lawn, you will almost certainly need to mow cool season grasses more often than once a week in spring.

Warm season grasses look best if you mow them more frequently during the summer. During the winter, warm season grasses should require litttle or no mowing, unless you overseed them with annual ryegrass for winter color.