Extension Educator, Horticulture
Grass grows and mowers mow -- continuously. You may look at mowing as a boring, time consuming and air polluting chore or you may have a Zone-like relationship with your lawn mower. The minute your backside hits the topside of the mower seat, you zone out.
How ever you view mowing, as a society we are in love with the appearance of freshly mown lawns. But there is more to mowing than turning the mower on and taking off.
University of Illinois Extension's Lawn Talk http://www.urbanext.uiuc.edu/lawntalk/ offers these guidelines for proper mowing.
Mow lawns at the appropriate height. A common mistake is mowing lawns too short. For most lawns, a mowing height between 2 to 3 inches is best. When the grass is growing well, 2 inch height is fine. When the grass is under stress from drought, heat or too much shade then 3 inches is better. The first mowing in spring or in preparation for overseeding can be slightly lower than normal. Lawns mowed at higher heights have deeper roots, less weed problems, and look much better. Simply raising the mowing height can have a major impact on lawn quality.
Remove no more than one-third of the leaf blade at any one mowing. Severe grass cutting causes reduced root growth. If the lawn "gets away from you" to six inches tall, mow it at four inches than a couple days later mow down to two inches. Mowing on a regular basis according to grass growth is essential. Don't mow wet grass.
Leave short clippings on the lawn. As long as the lawn is mowed on a regular basis and the clippings readily filter back down into the lawn, clippings do not need to be collected. Short clippings readily decompose since they are mostly water (75 - 80 percent) and do not cause thatch. Clippings also recycle nutrients, in particular nitrogen, so less fertilizer is needed. A study at the University of Illinois showed mulching mowers did not provide any additional benefit over conventional rotary mowers returning clippings (assuming proper mowing frequency and lawn fertilizing are followed).
Keep mower blades sharp. Dull blades tear the leaf causing a ragged appearance. The lawn may have an obvious browning of all the leaf tips. Also diseases can easily come in on a ragged leaf edge.
Mow in a pattern that is safe and convenient. Football and baseball fields often have a characteristic mowing pattern to provide some visual panache to the field. On golf courses putting greens have to be mowed in different patterns so a grain that effects ball roll doesn't develop. Taller lawns such as our home lawns are less prone to developing grain. Change mowing directions if it is convenient and safe. It can reduce soil compaction in certain areas.