We mow lawns to keep them looking neat and allow light to reach the leaf blades. Plants make their own food through the process of photosynthesis, which occurs in the leaves. The longer the blade, the more leaf surface for photosynthesis, the more food made, the longer the root system, the greater the ability to reach water and nutrients, and the healthier the plant.
When grass is cut too low, photosynthesis is decreased and the crown (or growing point) may be injured. When grass is cut too high, long blades shade each other and reduce photosynthesis. Uncut grass has an unattractive shaggy, open, coarse texture. The following mowing heights are recommended:
To determine when to cut the lawn, follow the rule of one-third. Never remove more than one-third of the leaf area at any time. To maintain a lawn at 4 inches, you must remove 2 inches when the grass reaches 6 inches – cutting the lawn every time it grows two inches. So, the taller the height of the grass being maintained, the less frequently it must be cut.
Cut the grass only when it is dry. Keep the mower blade sharp. Keep the discharge chute clear and mow in alternate patterns. Clippings contain 30 percent of the nitrogen needed for a well-managed lawn. By cutting the lawn frequently enough, clippings can be left on the lawn to provide organic matter and recycled nitrogen.
Clippings decompose quickly and do not contribute to thatch. If the lawn is mowed infrequently, clippings are too long, become matted on the lawn, exclude light and can damage patches of turf. In that case, they should be raked up or caught in a lawn mower bag and recycled in a compost pile. Mulching mowers are designed to cut turf blades repeatedly, so blades are in small pieces when they fall back on the lawn and easily filter to the soil surface. Mulching mowers don’t work well if the grass is too wet or if the clippings are too long.