News Release Distributed 04/29/11
By LSU AgCenter Horticulturists Dan Gill, Kyle Huffstickler and Allen Owings
Midspring is here, and it’s time to mow, mow, mow.
Mowing has a measurable effect on the way a grass plant grows. The ability of grass to sustain itself through frequent close clipping is one factor that distinguishes a grass species as a turfgrass. Grasses such as wheat, corn and oats, for example, cannot tolerate the harsh treatment of frequent mowing.
The rate of growth and the height of cut determine the frequency of mowing. The rate of growth depends on the type of grass, soil fertility (especially nitrogen content) and weather.
Lawns in Louisiana are made up of warm-season grasses. These grasses grow fast and need to be mowed frequently in the hot summer when moisture is adequate. A general rule is to mow before the grass becomes one and a half times as tall as the cutting height of your mower. Or another way to say this is: Do not remove more than one-third of the grass at any one clipping. For example, if the height of cut is 1 inch, mow when growth reaches 1 1/2 inches in height. If you continually allow your grass to grow too tall between mowings, you may end up with a thin, weedy turf.
You can decrease the frequency of mowing by choosing a slower-growing turfgrass, reducing the rate of nitrogen fertilization and raising the cutting height of your mower. The rate of nitrogen fertilization and the frequency and height of cut are major factors that determine the quality of turf.
Mowing height depends on the type of grass you have, your objectives and your willingness to work.
Most people mow with rotary mowers that have horizontal blades that flail the grass and fray the leaf blades. A rotary mower becomes noticeably duller after a few cuts and should be sharpened as needed. Some tough grasses like the zoysia will dull a blade quickly.
Reel mowers have clean, scissorslike cuts and produce a better-quality turf than rotary mowers do. A reel mower is more difficult to sharpen, but it should require less frequent sharpening. A reel mower may be more expensive, but it is normally more rugged and uses less fuel. Most reel mowers are particularly recommended for Bermuda grass and zoysia. A smooth turf, free of sticks, stone and other debris, is necessary when using a reel mower.
Removing grass clippings isn’t necessary if you mow as recommended. Research has shown that moderate amounts of small clippings decompose rapidly in warm weather with good moisture. Nutrients in the clippings are recycled without contributing greatly to the thatch layer. And if you don’t remove the clippings, you can get by with less nitrogen fertilizer.
Clippings should be removed, however, if they leave clumps on the grass surface. This normally occurs only if the grass is allowed to grow too high before mowing or if it’s mowed when wet. Zoysia and centipede grass leaves do not decay as readily as leaves of other grasses, so clippings need to be collected and discarded when growth is rapid – especially with zoysia.
Visit LaHouse in Baton Rouge to see sustainable landscape practices in action. The home and landscape resource center is near the intersection of Burbank Drive and Nicholson Drive (Louisiana Highway 30) in Baton Rouge, across the street from the LSU baseball stadium. For more information, go to www.lsuagcenter.com/lahouse and www.lsuagcenter.com/lyn.
Rick Bogren