Mow Your Lawn at the Right Height

Every time you mow, you help create conditions for grass to thrive – or to fail. Proper mowing is a means to cultivate a healthier lawn, combat the growth of weeds and prevent lawn disease. Here’s how:

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Mowing Promotes Healthy Growth

It's easy to see a lawn as one cohesive unit – an even swath of green. But it’s important to remember that a lawn is composed of individual grass plants. Just like other garden plants, when you pinch (mow) grass plants, they branch and become fuller, resulting in a more even turf.

If you overdo it and remove too many leaves (mow the lawn too short), grass plants won't have enough foliage to sustain healthy growth. A lawn that is mowed too low will be thin, weak and sparse, dry out quickly, as well as have a poor root system. Such a lawn is prone to weed infestations and disease outbreaks.

If you don't prune (mow) grass often enough, plants become lanky, causing the lawn to lose its durability and usefulness. It can also invite insects such as lawn Grubs and even small rodents. Grass that's too tall is also difficult to mow.

If you prune (mow) grass at the proper height, you'll create a dense, deep rooted lawn that needs less water and is not easily infested by weeds.

How High To Mow

Mowing turf at the proper height is vital for a healthy lawn, but ideal height varies based on grass type, even variety, time of year, and growing conditions. Grass requires more frequent mowing during its peak growth period and a higher mowing height during the hottest time of the year.

Rule number one -  try not to remove more than one-third of the leaf surface at any one mowing. Determine the ideal height for your grass and allow it to grow one-third higher before you mow again. To set mower height, place it on a flat surface, such as a driveway, and measure the distance from the ground to the blade with a ruler.

For cool-season turf, such as Fescue or Kentucky Bluegrass, active growth occurs during spring and fall. Typical cool-season grass height range: 2.5-4 inches.

For warm-season grasses, including Zoysiagrass, St. Augustinegrasss and Bermudagrass, peak growth occurs during summer. Typical warm-season grass height range: 1-3 inches.

During peak growth periods, expect to mow grass once every 5-7 days. Conversely, during times of slowest growth, you'll mow less, maybe not at all.

Follow these general guidelines for mowing heights. Newer dwarf grass varieties, which can be mowed shorter and less often, are becoming increasingly available.  So, check with your local Cooperative Extension System offices (link) or sod or seed suppliers, for recommended mowing heights for your area.

Grass Type

          General Grass Height (inches)

Cool-season grasses

   

 Fine Fescue

          1.5-3

 Kentucky Bluegrass

          1.5 -3

 Perennial Ryegrass

          1.5-2.5

 Tall Fescue

          2-4

   

Warm-season grasses

   

Bahiagrass 

Bermudagrass

          2-3

          0.5-2

 Buffalograss

          2-4

 Centipedegrass

 Kikuyu grass

          1-2

          1-1.5

 St. Augustinegrass

          2-3

 Zoysiagrass

          1-2

Taller is Usually Better

It's often best to maintain grass at its tallest recommended height, especially during the heat of summer or drought conditions. Cool-season grass usually grows best when maintained at a taller height, as do grasses growing in shade. Taller grass has deeper roots so it can draw from a larger moisture reservoir. Taller grass also shades soil, reducing water loss from evaporation and helps prevent weeds from invading your lawn.

Some warm-season lawns, such as hybrid bermudagrass, are mowed at lower heights for best appearance. However, mowing to a height of 1-inch or lower usually requires a more expensive reel mower as opposed to the rotary mowers most people own. Many gardeners prefer the look of a shorter lawn, especially during cooler seasons.  Just remember, consistently mowing at the upper end of the recommend mowing height range during hot weather or drought, is the best path to a healthy lawn.

Other Mowing Rules

  • Mow only when grass is dry.
  • Mowing during the cooler part of the day is easier on the mower and you.
  • Keep mower blades sharp.
  • Alternate mowing patterns and directions to avoid creating ruts and compacted soil.
  • Leave the clippings. If the lawn is mowed as often as it should be, decomposing grass clippings add organic matter and nutrients to the soil. Mulching mowers are also very effective at recycling clippings.

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