What Makes a Riding Lawnmower Not Cut Well?

With so many choices in power mowers, it might be tempting to choose a macho, zero-turn beast to ride around your lawn -- unless your lawn is smaller than a college quadrangle. A riding mower, however, is more cost-effective for use on a typical suburban yard, and it completes the job without continual dizzying turns. Whatever your choice, avoid simple mistakes for a good cut.

Along with annual riding lawnmower engine and battery maintenance, include blade sharpening and balance as well as repairs to worn rollers. A dull blade chops grass blades unevenly, leaving shredded edges that dry out and turn brown. An unbalanced blade swings unevenly, digging into turf and, occasionally soil, making a sloppy cut. Those little rollers on each side of the blade housing hold both sides of the housing at the same distance above the soil. A worn or missing roller puts a tilt on each pass, resulting in strips of grass that appear as if they were missed by the mower.

Mowing in the same direction each time and over the same area multiple times leaves flattened lines and irregular patterns in turf. So before mowing, plan your pattern -- spiral or rows -- to fit your lawn’s shape. Mow one way one time and the opposite way the next time, overlapping passes to avoid leaving uncut strips that you’d have to go back to get. Although it’s best to mow across hills with a hand mower, a riding mower should go up and down hills, and that takes planning, too.

Some long-ago suburban sage posited that scalping a lawn in spring encouraged it to grow faster. The sage is wrong. Scalped grass encourages shallow root development, which results in dead patches. Every variety of grass has an optimum length that balances a grass blade’s ability to perform photosynthesis with its urge to replace tissue lost to mowing. Removing no more than one-third of a grass blade at each mowing and mowing frequently -- as often as every three days -- answer both needs. Adjust that sharp, finely balanced riding mower blade to the shortest height for the variety; Bermuda grass "Sundevil" (Cynodon dactylon "Sundevil"), hardy from U.S. Department of Agriculture (USDA) plant hardiness zone 7 through 10, grows best when kept between 3/4 inch and 1 1/2 inches tall. Kentucky bluegrass (Poa pratensis), hardy from USDA zone 3 through 7, on the other hand, thrives at 2 to 3 inches. Taller height in hot weather shades crowns, which are the areas where roots and stems meet. Take it easy, too; driving a riding mower too fast might tear up or miss grass.

Under some conditions, a riding mower has no option but to scalp, tear or miss grass entirely. Some turns are too tight, and some corners can be reached with only a rotary mower or weed trimmer. So either of those tools should be used to finish small areas. Uneven lawns will be scalped unless they are rolled or plugged and the person operating the riding mower spans some swales entirely, leaving grass that lines them uncut but possible to mow with a rotary or reel mower.