Mowing Heights

Urbana-Champaign, Illinois (August 1, 2011)--Without doubt, homeowners spend the majority of their landscaping time mowing their grass. According to Rhonda Ferree, extension educator in horticulture, proper mowing is not only essential for the proper look, but also to assure good grass health. As you mow this summer, consider these few simple guidelines – you might even find you mow less!

For most lawns, a mowing height between 2 to 3 inches is suggested, with the upper range best for summer. Lawns mowed at higher heights tend to have deeper roots, less weed problems, and look much better. Mow higher when the grass is growing slower, under stress, or in the shade. This will help improve the grass health.

If is often advisable to mow higher during periods of intense summer heat. Taller grass plants with higher density have a profound shading effect on the soil surface, which reduces germination of weed seeds, particularly crabgrass. This is an excellent way to reduce herbicide use, especially where the lawn is properly fertilized and watered to maintain vigor.

Turf should be mowed as necessary, not according to a preset schedule. Turf grasses grow at different rates depending on weather, management, and species. University of Illinois recommendations are to never remove more than one-third of the grass leaf in any one cutting. For example, Kentucky bluegrass being maintained at a two-inch height should be mowed when it reaches three inches.

Should you collect the grass clippings or not? If you follow the one-third rule mentioned above, the clippings readily filter back down into the lawn and do not need to be collected. Clippings contain 75 – 90 percent water and readily decompose and add nutrients to the soil, not causing thatch. However, if the grass is extra-long, clippings may need collected to prevent smothering the grass underneath.

The mower you select is mostly a personal preference. Rotary mowers are the most widely used type on home lawns. A study at the University of Illinois showed mulching mowers did not provide any additional benefit over conventional rotary mowers, assuming that proper mowing frequency and fertilization was followed. The old-fashioned reel-type push mowers and electric mowers are becoming popular for small lawns. Regardless of the type of mower, blades need to be kept sharp.

Mow in the direction that is safest. You can occasionally change direction, but mowing the same direction each time should not be a problem on taller turf typical of home lawns. Mowing patterns can add interest to your lawn, such as you see at professional ballparks.

We spend a lot of time mowing our grass so it is important to do it properly. Try to enjoy mowing and use the time wisely. Rhonda says that she does her best landscape planning while mowing. For more information on this or other horticultural issues, contact your local Extension office by visiting www.extension.illinois.edu. You can also post questions on Rhonda's facebook page at www.facebook.com/ferree.horticulture.

Contact:

Rhonda J. Ferree
ferreer@illinois.edu