Mulching blades for mowers are tiered to cut each blade at least twice.
YOU CAN WATER IT TOO MUCH, or too little. You can fertilize too often, or let it go hungry. The absolute fastest way to screw up your lawn, however, has to do with the task you probably undertake most frequently: mowing.
Right now, during peak mowing season for much of North America, it’s important to review some basic rules that will keep your lawn lush now and, most importantly, later in the season when growing conditions likely won’t be as optimum.
1) Keep the Blade Sharp — Believe it, or not, it’s best to have your mower’s blade sharpened (or do it yourself) every eight to 12 hours of use. Dull blades tear grass rather than cut it. I like to keep two blades for the same mower in my garage; that way one can always be kept sharp and I don’t have to run the risk of mowing with a dull blade when the lawn gets tall.
2) Blade Height — Lawns should be cut no lower than 3 inches in height until the onset of autumn. The only exceptions to this would be lawns containing a predominance of one of three species of grass: bentgrass, Bermudagrass or seashore paspalum. These three species can be mowed as low as one inch high. Allowing the grass to stay tall now will keep many weed seeds from germinating — especially those crabgrass seeds that need light to germinate; keeping the lawn tall throughout the summer will keep the surface of the soil from drying out and reduce the need for watering.
3) Following the Rule of Thirds — No more than one-third of the grass plant should be cut at any one time. In other words, if the grass grows to an average height of 6 inches, it should be cut to no lower than 4 inches on its next mowing. After a 48-hour recovery period, the lawn can then be mowed again down to 3 inches. Here’s a good video from Cornell Cooperative Extension agent Dr. Frank Rossi, a turf specialist, who explains the rule: http://www.youtube.com/watch?v=guFJDNP9j9s.
4) If Your Lawn Gets Away From You — The top mowing height on most mowers is no higher than 4 inches, so what do you do if the lawn grows taller than 6 inches? I make sure no children are around and push down on the handlebar of the mower so the front tires lift into the air. This will generally allow the grass to remain at about 6 to 8 inches tall after the first pass of the mower. I also use a scythe on the areas of my lawn that I only mow once or twice a year. That’s one of the oldest — and most satisfying — grass-cutting tools on the planet.
4) Avoid Mowing When Wet — All precautions should be made to avoid mowing lawns during or just after rain, or when heavy dew is present. Grass tears easily when wet and the mower tires are more likely to do damage to the lawn.
5) Don’t Mow When No Rain is Predicted — If the long-range forecast calls for no appreciable rain and you do not have an irrigation system installed and in regular use, the lawn should not be mowed again until the day before substantial rain is predicted.
6) Recycle Clippings (Three Bagging Exceptions) — In general, grass clippings should be “mulched” or recycled back onto the lawn to restore nutrients to the lawn. As such, mowers should be equipped with mulching blades, which cut the blades at two heights — thereby dicing up the grass so it will biodegrade more quickly. Any areas of heavy clumping of grass clippings should be spread out with a rake and, in some extreme cases, the grass clippings should be removed to a compost pile. Bagging attachments are recommended in three circumstances: 1) in spring, if leaves and other debris remain heavily distributed across the lawn; 2) in late spring when dandelions set seed; 3) in fall, when leaves are heavily distributed across the lawn. In all circumstances, materials gathered in mower bags should be recycled and composted.
7) Turf Tires — Any large mowing machines should be equipped with turf tires designed to spread the weight of the mower across a wide area.
8) Striping and Overlapping — For most attractive appearance, lawns should be mowed in straight-line patterns, with overlapping by an average of the tire width in each direction. Mowing one course around the perimeter of a lawn area is recommended prior to commencing the striping pattern. The direction of the striping should be changed on subsequent mowing, either in a perpendicular or diagonal direction. Clippings should not be “blown” into surrounding planting beds.
9) Proper Use of Line Trimmers — Learn the proper use of line trimmers to: 1) avoid harming trees and shrubs; 2) avoid harming fence posts, siding and other stationary items; 3) avoid scalping the lawn to lower than 3 inches.
10) Observe the Lawn for Changes — If you see noticeable changes occur such as weeds, discoloration, insect infestations or dying patches of grass, do your best to diagnose the problem — or consult an organic lawn care professional. The problem, mind you, may not be not enough fertilizer or water.
11) Keep the Mower Clean — Mowers can easily spread fungal disease and even weed seeds, thereby contaminating an otherwise healthy lawn. If your lawn mower never leaves your own yard, then use your best judgement regarding cleaning. But if you hire someone to mow your lawn, you should really require that your mowing professional hose off his or her mower’s blade and undercarriage prior to firing it up on your grass.
12) Use Common Sense About Safety — Mowers, especially rotary mowers powered by gasoline engines, are inherently dangerous. They are capable of propelling rocks and other debris great distances and the moving blades are capable of severing hands and feet. Never reach in anywhere near the mower blade without disengaging the spark plug; always be aware of where your mower is discharging the grass.
Source: http://www.safelawns.org