Watch Out for “Mower Blight”

When you start mowing your lawn this season, I bet you plan to use the same pattern that you used last year. Why? I expect you’ll say “…because it’s the most efficient.” Maybe it’s a square, working inward, or it’s back and forth, creating professional-looking stripes. Perhaps your mower discharges clippings to the right so you mow with the walkway or flowerbed on your left. Regardless of the pattern you use, keep an eye out for gouges, bare spots or other odd markings on the lawn that might indicate “mower blight,” correctable by modifying your mowing habits.
Every mower exerts ground pressure on the turf. The rollers on reel-type mowers, working in the same direction, repeatedly mash the grass so it grows almost horizontally, shading other grass plants. Mower wheels compact the soil and create stormwater runoff channels that eventually become very visible in the turf.
Today’s hydrostatic drive mowers with their speed and fast-reacting controls bring other problems. With a zero turn radius (ZTR), close maneuvering can turn the wheels in opposite directions at different speeds, creating a pivot divot—a bare spot where the vertically rotating wheel compacts and scrapes the ground, scrubbing as it turns.
To avoid mower blight, it’s best to vary your mowing route. With a ZTR, use patterns that minimize hillside turns. To prevent the pivot divot, intermittently back your mower into a tight spot or make a slower turn. Mow at an angle. Mow in curves that follow some feature of the landscape. To shift the ZTR from its regular path, occasionally do your trimming around beds and walks with a push mower. You’ll enjoy the exercise.
More Mowing Tips
- Be safe. Before you start the season, check for low-hanging branches and perform some judicious pruning. Playing “dodge ‘em” on a steep slope can be unhealthy.
- Make your turf more mower-friendly.
- Enlarge the mowing circles around trees to make an easier curve.
- Group several shrubs together into one large mulched area.
- Use ground covers or pavers in tight spots.
- Mow cool season grasses high—three inches minimum. Longer leaf blades have more area to photosynthesize, preparing for the summer heat and shading out a few weed seeds carried in by the wind.
(An earlier version of this article appeared in the Asheville Citizen-Times in 2003.)
Written by Glenn Palmer, Extension Master Gardener Volunteer