What Length Should a Lawn Be Cut To?

Height

• If you aren't sure what type of grass you have, cut to a height of 2 to 3 inches. If you know the variety of grass in your lawn, you can be more specific about the height. In spring and fall, cut Kentucky bluegrass, perennial ryegrass and fine fescues to a height of 2 to 2 1/2 inches. Cut tall fescue and St. Augustine grass to a height of 2 1/2 to 3 inches. Centipede and bahiagrass do best at a height of 1 1/2 to 2 inches. Allow Kentucky bluegrass, perennial ryegrass and fine fescue to grow 1/2 inch taller in midsummer to compensate for heat and water stress.

Mower

• Adjust push mowers so that all four wheels are set on the same notch. If you are using a riding mower, make sure the tires are equally inflated so that the blade is level. Park the mower on a solid surface, such as a driveway, and measure the distance between the surface and the blade. Turfgrass loses less water and experiences less stress when the mower blade is sharp and makes clean cuts. Ragged cuts take a long time to heal.

Shade

• Shaded grass is thinner with fewer blades, but because it gets less sun, it needs more surface area to perform photosynthesis. Mowing shaded grass to a taller height helps compensate for these problems. The University of Wisconsin Cooperative Extension recommends cutting grass grown in shade to a height of 3 to 4 inches. A taller mowing height also protects the growing points and helps the grass tolerate foot traffic better.

Mowing Frequency

• Grass experiences stress and physiological shock when you mow. To reduce adverse effects, mow often enough that you never have to remove more than a third of the height at one time. For example, to keep the lawn at a 2-inch height, mow when the lawn height reaches 3 inches. When a lawn is significantly overgrown, set the mower height as high as possible and rake up the clippings after mowing. After the first mowing, gradually reduce the grass length by mowing more frequently than usual, removing no more than a third of the height at a time.