Bio Green Outdoor Services, LLC Lawn Care & Sprinkler Learning Center (703) 450-0034

Mowing is an important management factor for quality turf. Decisions that the homeowner makes about frequency, mowing height, and clippings are critical. Many lawn care problems are a result of not cutting at the proper height and not keeping lawn mower blade sharpened throughout the season. No matter the kind of grass you have, there is a simple “rule of thumb” to follow when mowing your lawn: never remove more than one-third (1/3) of the leaf surface each time you mow. Leaf surface refers to the length of grass above the soil. Cutting the grass creates stress on the plant, and if turf is mowed too closely, root growth is slowed. This invites heat and drought stress and welcomes weeds. In addition, it gives the lawn a yellow/brown color. With cool-season grasses, selecting the highest recommended mowing height increases the likelihood of the grass surviving drought by decreasing soil temperatures. Your cutting frequency will depend on weather conditions, the fertility program, and amount of water the lawn has received. For cool-season turfgrasses, optimum mowing height will change with the seasons. The first cut of the year should be made early and at a lower setting (1½ – 2”). This will help stimulate growth and remove “tip burn” from winter. The height should be raised as temperature rises. Late Spring through early Fall, mowing height should be set to 2 ½ – 3” (sometimes as high as 3½” in heat of summer). As temperatures decrease, mowing height should be lowered until the final cut of the year (back down to 1½ – 2”).

Lawn Mower Maintenance

Be sure to keep mower blades sharp! You should sharpen the blade several times throughout the year. Using a dull blade causes excess leaf damage. Dull mower blades “shred” leaf tips instead of cutting them cleanly. Shredded tips are wounds that the grass plant will eventually not be able to heal and can enable fungus problems, stress the lawn, and give it a yellow/brown color. It is also important to keep the underside of the mower clean.

Lawn Clippings

Clippings can be left on the lawn as long as they disperse well and are not clumped together. Mowing turfgrass areas that are too wet can be detrimental to the turf. This leads to clumps of clippings that shade and smother turf. Tip “shredding” can also occur when mowing wet grass. Returning clippings (mulching) continues to be a controversial practice because it was thought to increase thatch buildup and possibly increase disease problems. Research has shown, however, that in healthy turf that is otherwise properly managed, returning (mulching) clippings does not significantly increase thatch buildup. If however, there is an active disease problem, mulching clippings will make control more difficult as they are a source of re-infection. Clippings do have significant nutrient value. They normally contain 3 – 4% nitrogen, 0.3 – 0.5% phosphorus and about 2% potassium and, like any fertilizer, should not be left on walks and driveways where they can runoff and pollute waterways. Collecting and bagging clippings to be sent to the landfill is a job no one likes and is also a waste of landfill space. Returning clippings is an environmentally sound practice.

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