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Is your lawn mower at the right height?

Proper mower height helps keep your grass happy and healthy.

Editor’s note: This story is part of Denver Water’s TAP series on water-wise landscaping tips done in partnership with the Associated Landscape Contractors of Colorado. Subscribe to TAP to make sure you catch the rest of the series.

If you enjoy having a great-looking yard, the four wheels on your lawn mower can play a big role.

That’s because setting the wheels on the mower to the proper height is one of the most important aspects of having healthy grass throughout the summer.

Grass looking stressed? Try running a sprinkler audit

“Simple steps like setting your lawn mower to the proper height show how easy it is to improve the health of your yard without using more water,” said Austin Krcmarik, water demand and efficiency planner at Denver Water. “We encourage all of our customers to look at their yard and see what steps they can take to use water more efficiently.”

The Associated Landscape Contractors of Colorado, along with landscape experts at Colorado State University's Extension, recommend Kentucky bluegrass be cut to a height of 2.5 to 3 inches throughout the growing season. 

“Mowing to that height may seem high to a lot of people, but it’s what’s best for the health of your grass and the responsible thing to do in the West, where water is a scarce resource,” said Lyle Fair, a landscape expert with the Associated Landscape Contractors of Colorado.

Proper mower height is a simple way to help your lawn stay healthy throughout the summer and make it more resilient to drought and weeds. Photo credit: Denver Water.

Benefits of the right height

Mowing to the recommended height of 2.5 to 3 inches means having longer blades of grass that provide several benefits, including:

  • More shade, which keeps the soil cooler and allows moisture to remain longer and not dry out as fast. 
  • Deeper root development, which will sustain the plants through hot days.
  • Healthy grass is better able to withstand hot, dry weather and fight off diseases and insects.
  • More shade makes it harder for weed seeds to get the sunlight needed to sprout.
Setting the height of your lawn mower to 2.5 to 3 inches is the recommended height for Kentucky bluegrass in Colorado. Photo credit: Denver Water.

Too short = too stressed

Many people cut their grass too short. They may not have to mow as often but this practice often leads to unhealthy grass and the potential to kill the grass due to stress. 

Remember, the blades of grass are the plant’s leaves, which are needed for the plant to survive and to provide oxygen for YOU.

How to set the mower’s height

Check your owner’s manual for details on how to properly adjust your mower. But in general, it’s simple: 

  • Make sure mower is turned off and remove the spark plug to prevent an accidental start.
  • Place the mower on a flat surface, like the sidewalk or driveway. 
  • Use a ruler to measure the distance from the sidewalk to the bottom of the mower.
  • Use the levers on the wheels to adjust the height of the deck to 2.5 to 3 inches.
  • Measure the height of the grass after it’s been mowed to double-check the adjustment.
Use a tape measurer or ruler to measure the distance from a flat surface to the bottom of the mower deck to determine the height of the mower. Photo credit: Denver Water.
Adjust the levers on the wheels of the mower to raise or lower the height. Photo credit: Denver Water.

More mowing tips!

  • Use a mower that leaves grass clippings on the yard instead of bagging them. The clippings decompose quickly and provide a source of nutrients and organic matter.
  • Mowing should be done frequently enough so that no more than 1/3 of the grass height is removed during any single mowing. 
  • You may need to mow grass every three to four days in the spring when the grass is actively growing, but only once every seven to 10 days in the middle of the summer. 
  • Make sure the mower blade is kept sharp to ensure clean cuts. 

CSU Extension has additional mowing and lawn care tips

“Having the correct lawn mower height is a simple fix that improves the health of the grass without using more water,” Fair said. “It helps your grass, saves money on your water bill, and conserves water from our snowpack and mountain streams.”

The Associated Landscape Contractors of Colorado is the premier professional organization for Colorado’s landscape companies. ALCC promotes the responsible use of water and other natural resources and provides educational and industry certification opportunities to Colorado’s landscape professionals. ALCC’s Sustainable Landscape Management and Community initiative promotes the use of sustainable maintenance practices that reduce water use and loss of plant life. 

For more information on ALCC or to find a landscape professional, go to or call 303-757-5611.