Precision=Profit

While you may have many years of mowing and maintenance experience in your back pocket, it never hurts to refresh your knowledge of proper mowing heights. After all, maybe the problem you're having on Mrs. Jones' lawn can be solved with a slight mower adjustment.

Mowing turf at appropriate heights and frequencies is a major component of a turf management scheme designed to develop a dense, actively growing, attrac­tive turf.

Conversely, mowing is a destructive practice; it reduces turfgrass leaf area available for producing necessary plant metabolites and also opens leaves to possible disease entrance. In addition, when mowed too short, turf can become open, allowing weed invasion (especially annual weeds such as crabgrass). Finally, turf mowed too short often has poorly-developed root systems and reduced rhizome spread, which alsocontributes to the development of a thin, open turf.

Thus, for these reasons, it is important to find the balance that produces attractive, healthy turf in an efficient manner. To help turf managers find the balance between turf and human needs, information about mowing height, mowing frequency, general mowing practices, handling clippings and types of mowers requires consideration.

By mowing frequently and maintaining a uniform turf surface, a neat appearance can be achieved, even at taller heights. Un­ fortunately, however, a common perception is that a short turf is superior in appearance to tall turf. In reality, turf that is uniform ap­ pears neater than uneven turf, regardless of height. Proper height and frequency are the two most important aspects of a turf mowing program.

Mowing turf at the appropriate height is important to turf health and appearance. Turf cut too short usually has a shallow root system, lacks density, and often requires pesticide applications to stave off weed and pest infestations that commonly occur in stressed lawns. Conversely, tall turf is often considered to be unattractive because of wide leaf blades, low density and a clumpy, unkempt appearance. In addition, tall turf may not be satisfactory for some sports applications.

Mow turf grasses according to the heights presented in the sidebar. Note that a range is listed for each species. When healthy and actively growing, turf can be mowed at the lower heights; raise mowing heights within the desired range during warm-hot periods or when turf is stressed due to drought, disease, shade, insects or traffic. The heights listed here provide a balance between turf appearance and health.

Source: University of Illinois at Urbana-Champaign, Texas Cooperative Extension, The Georgia Gardener

Turf should be mowed as necessary, not according to a preset schedule. Turf­ grasses grow at different rates depending on weather, management and species. A basic recommendation is to remove no more than one-third of the grass blade at anyone mowing. For example, Kentucky bluegrass being maintained at a 2 inch height should be mowed when it reaches 3 inches. This "one-third rule" will help maintain maximum turf root growth. Re­ moving more than one-third of the grass blades may cause root growth to cease while the leaves and shoots are regrowing. This practice can be especially destructive if practiced continuously over a period of successive mowings. Roots may not have a chance to fully develop and the plants will thus be more susceptible to environmental and management stresses. Maintenance of healthy, growing turf root systems should be a primary consideration of any turf manage­ ment program. - Tom Voigt, University of Illinois at Urbana-Champaign