   Check Out Your Lawn Mower - October 17, 2001 Jeff Schalau, County Director, Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County This is the time of year that cool season lawn owners need to pay attention to their turf. Cool season grasses are those that stay green year-round and our most common species are Kentucky bluegrass, perennial rye, tall fescue, and fine fescues. These turf types are just now coming out of their summer dormancy and starting to need some attention. Giving these grass species TLC between now and next spring will go far to prevent disease and weed problems next summer when they return to dormancy. Proper mowing begins with functional, well-maintained equipment. How is your mower doing? Is it doing more damage than good to your lawn? Is the blade sharp and balanced? Can the mowing height be adjusted and are all the wheels set at the same height? Are you mowing at the correct height for your turfgrass type? How often should your lawn be mowed? I will try to get these questions answered and assume that most people are using a rotary mower as opposed to a reel mower. First, lets assess the current mowing situation. A well-mowed lawn should have an even surface and the leaf blades should have a cut rather than a shredded appearance. Get on your hands and knees and look at the grass tips. If the blade tips look as if they were beaten with a disc sander, then your blade is probably dull and/or out of balance. To check this out on a rotary mower, disconnect the spark plug wire and remove the spark plug. Next, look under the deck. If the blade feels dull, then it needs sharpening. This can be done at home with the proper equipment (a big metal file or grinder), but it is critical that the blade remain balanced and the correct cutting angle (about 45 degrees). If you are confused at this point, take the mower or blade to a repair shop to be sharpened. If your freshly mowed lawn has an uneven surface, check the wheel heights (front and back) by using a tape measure. Never do this while the mower is running and if you need to touch the blade, remove the spark plug. Next, roll the mower onto an even surface such as a concrete slab. If the wheels do not all touch the floor, then at least one of the wheels is not properly adjusted. You should also check to see if the front wheels are the same height as the back. Take your measuring tape and measure the vertical distance from the floor to the mower deck at each wheel. These distances should be the same at each wheel. Once properly adjusted, you may want to use a permanent marker to mark the wheel adjustors. Once your mower is sharp and level, determine the proper mowing height. Kentucky bluegrass (and bluegrass blends), perennial rye, and fine fescues should be mowed between 2.5 and 3.5 inches in height. Tall fescue should be mowed between 3 and 4 inches. A law of mowing that cannot be broken is the "one-third" rule. This rule tells you never to remove more than one-third of the total grass height at any one mowing. To remove more than one-third is to scalp which severely stresses the turf. I recommend mowing taller rather than shorter. This maximizes the photosynthetic leaf area, which will allow the grass to manufacture and store more energy. It also promotes deeper root growth, which becomes especially important during the summer months. Mowing frequency will depend the growth rate and the one-third rule. If you have recently fertilized, then the turf may require more frequent mowing. Remember: do not scalp and mow high if possible. If you look at your mower and decide that you need to start over, consider a mulching mower. This design requires no bagging and returns clippings to the lawn. Mulch-mowing saves time and makes a lawn greener and healthier by recycling the nutrients contained in the grass clippings. Mulch-mowers have specially designed blades that keep the mowed grass suspended longer under the mower deck. This chops and re-chops the clippings. The finely chopped clippings settle down into your lawn where they disappear from sight and decompose on the soil surface. Mulch mowing should be done every five to seven days during the spring. Some mulch mower designs also can be converted to bagging mowers. This is a handy feature when grass is growing rapidly or to collect weed seeds to minimize their spread. For additional information about fertilization, dethatching, and aerifying, consult the September 27, 2000 column called "Cool Season Turf Maintenance" on the Backyard Gardener Web Site http://ag.arizona.edu/yavapai/anr/hort/byg/. The University of Arizona Cooperative Extension has publications and information on turf establishment and maintenance. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at mgardener@kachina.net and be sure to include your address and phone number. |