Thursday, April 2, 2020
April 2, 2020

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Gardening: Raise mowing height for summer lawns


I mow my grass once a week at a 1 inch height. My neighbor suggested raising the height to almost 2 inches because it is better for the lawn. Which is better?

The leaves of all plants are where food is manufactured. Leaves absorb sunlight and combine carbon dioxide with water to create carbohydrates for growth and energy in a process called photosynthesis. More leaf area means healthier grass.

During cool spring weather lawns mowed short or long will grow well. It is during hot, dry, summer weather when longer mowing height will make a big difference.

Research has shown that grass root depth is directly proportional to leaf blade length. The longer the grass, the deeper the roots. Deeper roots withstand drought better and can go longer between irrigations.

The rule in mowing grass is to not remove more than 40 percent of the leaf blade. If grass is mowed at a 1 inch height, it should be mowed when it reaches 1 3/4 inches. If mowed at 2 inches, it can wait until it reaches 3 1/2 inches. So the longer you mow grass, the longer the interval between mowings. If you wait until the grass is 3 or 4 inches and then mow at 1 inch or less, you will be damaging the lawn. Golf course putting greens, which are mowed at a fraction of an inch, are mowed every day.

Because grass grows faster in May and June, it should be mowed more frequently than once a week. From July on, once a week mowing should be enough.

Your lawn will definitely be healthier and look better later this summer if you raise the mowing height.

Another frequent question about lawn mowing is whether to remove clippings or let them fall between grass blades. More frequent mowing means shorter clippings, which fall between grass blades more easily. Accumulation of clippings on top of the lawn are unattractive. However, occasional clumps of clippings can be scattered by running the lawn mower back over them. Clippings also stick to shoes and pet feet and are tracked into the house. This is sometimes reason enough to pick them up.

Clippings break down into humus over several months. The humus is converted into compounds which are available as fertilizer. One year’s accumulation of clippings is equivalent to one fertilization. That is definitely beneficial to the lawn.


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