How High Should a Lawn Mower Be?

Type of grass.

• In the spring and fall set the mower to the following heights for healthy, attractive grass.

  For Kentucky bluegrass, perennial ryegrass, fine fescue and Blue Gramma set the mower blades at 2 to 2 ½ inches. When cutting tall fescue set the height at 2 ½ to 3 inches.

  To cut Bermuda, Zoysia and St. Augustine grasses set the mower height at 1 to 1 ½ inches. When cutting buffalo grass set the height at 1 to 2 inches.

Summer Mower Height

• As summer approaches set the mower half an inch higher than it was set in the spring. The leaf area on the grass determines the root area underground. The larger root area absorbs more water and keeps the grass green through the summer. It also shades the soil, preventing it from drying out, and keeps weed seeds from sprouting. The higher mowing height is also recommended for any time the grass is under stress.

Reducing the Height of Tall Grass

• No more than one-third of the leaf blade should be cut off when mowing. When grass is more than four times the tallest recommended mowing height, set the mower to two-thirds the height of the grass, or the highest setting it will allow. Cut the grass, let the clippings dry and then mow again at a lower height in a different direction. To keep grass from getting too tall it will need to be cut at least once a week during its most active growing season.

Final mowing before winter

• Snow mold is a fungal disease caused by one of three different fungi. It grows in the dark under the snow when the temperature is between 45 degrees Fahrenheit and freezing, then continues to spread as the snow melts. To reduce the chance of snow mold set the mower 1/2 inch lower than the spring recommendations in the last two mowings in the fall. Where snow mold is common, grass should not be fertilized in the late summer or fall as this also encourages snow mold.