How high to mow?

Whether you are new to lawn care, want to have the most beautiful lawn in the neighborhood, or want to minimize your water usage, knowing how high to cut your grass is key to success. How do you know what is the best mowing height for your lawn?

The best place to start is on your state’s leading agricultural university’s web site, or by contacting the trained volunteers at your local Master Gardener program. The advice you get from these folks is the best, because their advice is the result of scientific testing in your local climate and soils.

Search the university’s web site for its turf management program. Here you will find guidance for all aspects of caring for your particular lawn grass, including watering, controlling pests, fertilizing and mowing. Check out the recommendations for how often and how high to mow your lawn at different times of the year, and for special circumstances such as helping your lawn to survive drought. You can even find photos to help you identify your turf grass, in case you are not sure what it is.

The information is often presented in a chart with a range of recommended mowing heights, such as “1.5 to 3 inches”. Choosing a height at the higher end of that range has many benefits. The blades of grass act as solar collectors that nourish the plant. Taller grass provides more energy for the grass and shades the soil so that moisture evaporates more slowly. The longer blades feed the roots more efficiently, encouraging deeper roots. Deeper roots mean the lawn will require less water and therefore be more drought tolerant because the deeper soil stays moist longer. Your lawn will not only be more drought tolerant, it will have a greener, lusher appearance. Taller grass tends to discourage weeds. Some weed seeds must have direct sunlight to sprout, so the taller grass casts shade on those seeds, preventing them from sprouting.

Taller grass means less work. Turf management experts say that it is best to mow often enough that you are cutting off no more than one third of the length of the blade in any mowing. If you set your mower to mow at one and a half inches, then you must mow every time the grass grows a half inch. If set it to three inches, you only have to mow every time the grass grows an inch.

Choose the best cutting height for your lawn and your grass will be greener, healthier, need less water and have fewer weeds than a lawn that is mowed too severely.

© Marjorie King
All Rights Reserved
Originally published in 2009, revised April 2015


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