There's more to cutting your lawn than starting the mower (05-15-2006)

The one activity that we perform on our lawn more than anything else is mowing. Yet, it is also the most often performed task done with lack of attention to mowing height, regularity, leaf wetness, or sharpness of blade. Any of these factors could cause undue turf stress and provide less than desired results.

Every turf species has its own optimum mowing height and any extremes from this may cause scalping, turf thinning, and even loss of the lawn. Shade intolerant species like bermudagrass, when maintained at a mowing height greater than two inches, will begin to drop lower leaves caused from the shading of the canopy above it. This often creates a scalped appearance, just after mowing, when the top canopy is removed and exposes the brown leafless stolons.

In contrast a St. Augustine lawn cut less than two inches in height may become wear stressed and lose turf density due to exposed stolons and reduced leaf area. Recommended cutting heights for our warm season turf species are as follows: bermudagrass 0.5-1.5 inches; zoysia 1.0–1.5; carpetgrass 1.0-2.0 inches; centipede 1.5-2.0 inches and St. Augustine 2.5-3.0 inches.

Regardless of the turf species, mowing regularity should follow the one-third rule. This means never remove more than one-third of the total turf height at a single mowing. Therefore, depending on the rate of growth and the desired maximum turf height, this could require mowing several times a week for a hybrid bermudagrass lawn or perhaps as little as once every two weeks for a centipede lawn under low water and fertility management.

Assuming the growth rate is the same for a bermudagrass lawn kept at a one inch height, and a St. Augustine lawn maintained at three inches, the bermudagrass lawn would require three mowings to one for the St. Augustine lawn.

When the one-third rule is followed leaf clippings will fall into the canopy of the turf and decompose rather quickly. With irregular and improper mowing excess leaf clipping collect on the turf canopy shading the turf below, increases disease and insect incidences, and creates excess thatch.

Blade sharpness will determine the quality of cut and aesthetic appearance of the turf. A dull mower blade will tear rather than cut leaving leaf tips split, ragged and brown. It is best to avoid cutting the lawn when there is leaf wetness from rain or heavy dew, especially when disease pressures are prevalent.

Published May 15, 2006

Dr. Wayne Wells is an Extension Professor and Turfgrass Specialist. His mailing address is Department of Plant and Soil Sciences, Mail Stop 9555, Mississippi State, MS 39762. wwells@ext.msstate.edu