More to mowing than meets the eye
Published: Saturday, March 16, 2013 at 6:01 a.m.
Last Modified: Thursday, March 14, 2013 at 10:08 a.m.
On the surface, it seems odd that something as simple as mowing could have an impact on turf health. Could there really be a right way and a wrong way to cut grass? In considering turf health, a key principle is managing the plant to minimize stress, and mowing practices are one of the key elements in this effort. Perhaps there is more to cutting grass than meets the eye.
Healthy turf depends on a vibrant root system to take up water and nutrients and the length of the grass blade — the amount of leaf surface available to collect sunlight and manufacture food — is an important part of maintaining the health of the overall plant. The University of Florida recommends letting leaf blades grow to 4 inches for bahia and St. Augustine grass, then cutting to 3 inches, except for St. Augustine dwarf varieties (Seville, Captiva and Delmar), which should be allowed to reach 2.5 inches, then cut to 1.5 inches. For centipede grass, allow the grass to grow to 2 inches and cut to 1.5 inches. Zoysia grass should be allowed to reach 3 inches and cut to 2 inches.
Frequency of mowing depends on several factors, including temperature, moisture and overall grass health and condition. Frequency will change with the day-length and seasonal weather factors, and it will be important to monitor grass and mow when needed. This is particularly a problem for commercial firms that like to mow on a set schedule. In spring, it may work to cut grass every 10 days, but during the warm, wet days of summer the schedule may need to be every five days. As a shortcut, firms sometimes lower the blades and cut too much leaf off the plant, essentially "scalping" the turf. Because the leaf blade performs a variety of functions (gathering sunlight to manufacture food, shading the root system, helping with transpiration), this shortened leaf stresses the plant during the most stressful time of year — when temperatures are the highest. Moreover, the roots are damaged by this action, making the plant less resistant to insect and disease problems. Sometimes this doesn't show up until the following spring, when grass has been damaged by cold weather because the root system was too weak to withstand freezing temperatures. If a commercial firm cuts your lawn, be on the lookout for attempts on their part to cut turf too short in order to maintain their schedule.
Over the years there has been discussion about grass clippings removal. Research has shown it is best to allow clippings to lay where they fall. If the proper mowing schedule is maintained, clippings will be short enough to break down and not contribute to excessive thatch. Clippings have nitrogen, so they will contribute to the health of the turf as they disintegrate. Remember to keep clippings out of swales, sidewalks and streets where they will wash into storm drains; this practice introduces the nitrogen into the water system and degrades surface and ground water.
It is important to keep mower blades sharp. Examine the end of the cut leaf blade. If it has a clean cut, the blade is sharp; if the end of the cut leaf has a shredded appearance, it is time to sharpen the blades. Mower shops will sharpen blades for a reasonable fee, and they can do a better job than homeowners.
Remember to change your mowing pattern from time to time, particularly if you use a riding mower. This helps avoid problems associated with soil compaction from heavy mowers, helps prevent wear patterns and reduces the grain (grass laying over in the same direction).
Finally, a few tips for safety. Before mowing, always scout the lawn for sticks, stones, children's toys, dog toys and like items that can become projectiles. Never mow when turf is wet, as this results in clumping which slows decomposition. Check the mower before each use for wear and service it at manufacturer-suggested intervals. Never fill a hot mower with gasoline. When mowing, wear heavy leather shoes with good, slip-resistant soles. Wash the mower deck after use to reduce rusting and movement of weed seeds.
There really is more to mowing than meets the eye. Turf health is influenced by many factors, some of which are beyond man's control. Paying close attention to the items one can control — including mowing practices — will reduce things that can go awry with turf management and will result in a healthier lawn.
David Holmes is Marion County extension director. Contact him at email@example.com.