How Mower Height Directly Affects Lawn Health

close up of grass with sunshine

Manuel Breva Colmeiro/Getty Images

The most important piece of advice for lawn care is simple: Mow the lawn so the grass stays long. Most lawns should be cut at a minimum mowing height of 2.5 to 3 inches, give or take a notch on your mower's adjustable wheels.


There are two major advantages to raising the height of your mower deck so that the grass is trimmed to a longer length: 

  • A longer lawn means that the individual grass blades (the leaves) have more surface area for photosynthesis to occur. Increased photosynthesis results in more plant growth, a more extensive root system, and a healthier plant.
  • Weeds are drastically reduced when the lawn is maintained at a higher cut. Once turf adapts to growing at increased heights, it fills in and becomes dense and lush, crowding out weeds that normally invade when turf is weak and stressed. Longer grass also means that the ground is more shaded, so that weed seeds do not get the sunlight they need to sprout. 


A dense, lush lawn maintained at a minimum height of 2.5 or 3 inches is more tolerant of infrequent watering and drought stress because there are increased moisture reserves in the leaf tissue and root system. Although your turf grass will still need water when mowed higher, the effects of drought or community watering restrictions will be less noticeable and will take longer to occur, This can be the difference between your lawn turning brown or making it until the next rain.

The most noticeable benefit of the longer turf is aesthetics. The increased amount of leaf blade surface makes for a dramatic improvement in turf color. After shifting to a higher mower height, you will find that the lawn becomes become consistent, uniform, and lush looking. When given the right opportunity, shade zones, patchy areas, and weak spots in the lawn will fill in and help achieve a dense carpet effect that every homeowner wants.  

Mowing Frequency

Your 2.5- or 3-inch lawn will need to be mowed once a week during the growing season, but contrary to popular belief, it will not cause you more work. Once the grass reaches that uniform height, you will still be cutting off the same amount of grass with each mowing. 

Of course, there are exceptions to every rule and this one is no different. Some southern grasses just don't like to grow that high and thrive just fine at lower heights. Also, in moist or wet climates, some lawn care experts advise giving your lawn a shorter "buzz cut" before winter snows come. This will keep the lawn from trapping a lot of moisture that can lead to fungal problems in the spring. Long grass can also be a haven for voles and other tunneling rodents seeking shelter under the snow in winter.