Department of Soil&Crop Sciences

  • Print
  • Email
  • Decrease text size
  • Increase text size

Mowing

Aggie Turf - lawn MowingIs the lawn smooth enough to mow with a reel mower? Is it smooth enough to mow at the optimal mowing height for the grass variety without continual scalping damage? Scalping will put grass at a competitive disadvantage and eventually lead to the decline of lawn quality. Evaluate the yard for high spots, low spots, and ruts to decrease scalping. Add soil to level out the lawn surface. Fill in ruts by lifting sod (in ruts) with a sharp spade and place topsoil underneath. Replace sod and keep the area moist for several days to help redevelop a healthy root system.

Selecting The Right Mowing Height

Aggie Turf - lawn MowingAll grass varieties should be mowed at or near their optimal mowing height. This will keep grass healthy and dense (highest number of shoots per unit area). Higher density means more soil surface shading, which severely restricts the germination of many annual grassy and broadleaf weeds. Maintaining a dense and healthy turf is the best weed control.

Selecting the right mowing height also means selecting the right mower. Do not invest in high density bermudagrass or zoysiagrass hybrid varieties if you plan to mow at three inches with a rotary mower. Many of the varieties available today require mowing height at or below one inch, which cannot be done effectively with a rotary mower.

VarietyMowing Height RangeOptimal Mowing Height
(Assumes Correct Frequency)
Buffalograss2 to 4 inches2.5 inches
Centipedegrass 1.5 to 2.5 inches 2 inches
Common Bermudagrass 1 to 3 inches 1.5 inches
Hybrid Bermudagrass 0.75 to 2 inches 1 inch
Kentucky Bluegrass 1.5 to 3 inches 2 inches
St. Augustinegrass 2.5 to 4 inches 2.5 inches
Tall Fescue 2 to 4 inches 2.5 inches
Texas Bluegrass (Reveille) 1.5 to 3 inches 2 inches
Zoysia japonica (coarse bladed zoysia) 1 to 2.5 inches 1.5 inches
Zoysia matrella (fine bladed zoysia) 0.75 to 2.5 inches 1 inch
How Often To Mow

Seasons, weather, and nutrient availability, are some of the many things that can affect grass growth. The best and most safe rule of thumb is to never remove more than 1/3 of the leaf blade at any one time. Lawns are being mowed too infrequently if there are piles of grass clippings left after each mowing. Consider a farmers hay field. Farmers remove close to 90% of the grass plants leaf surface when cutting hay. The grass left after the hay is baled turns a golden tan color. The color change take place because grass plants are not capable of recovering from large amounts of stress for quite a while. The small amount of leaf surface left on the plant is not enough to maintain the physiological activities (photosynthesis) for plant energy.

Grass plants have a "growing point" where all of the leaves originate. The growing point stays near the soil surface when grass is mowed frequently. When people let their lawns get really "hairy," the growing point begins to elevate from the soil surface. When finally mowed, the growing point may be cut and removed with the rest of the clippings. This means death to the plant. Frequent mowing, never removing more than 1/3 of the grass blade ensures that the growing point will stay near the soil surface and the turf will stay healthy and dense.

Blade Sharpening

Maintaining a sharp mower blade, whether rotary or reel, is essential to maintaining healthy turf. A smooth, clean cut not only looks better for the lawn, but also does much less damage to the grass plant. Dull mower blades thrash and beat the tops of the grass blades off. This leaves a ragged top which becomes straw colored and gives the lawn a tan colored hue. Ragged tops are prime points of entry for many fungal pathogens (turf disease causers) and small turf insects.

Be sure to have your mower blade checked and sharpened at least once per year. A rotary mower blade can be adequately sharpened using a good bench grinder and a tub of cold water. Here are a few steps to take when sharpening.

  • Always where safety glasses when grinding. Use cold water judiciously.
  • Try to keep the original angle on the mower blade by making smooth, quick swipes across the grinding wheel.
  • Dip the blade in cold water after every few swipes across the grinding wheel so you don't lose "temper" in the steel. If you see blue in the blade where you are grinding it means that the temper is lost in that area and the steel is now very soft . There will most likely be a chip in that spot next time you check your blade.
  • After grinding the blade angle, test for proper balance. Place the blade on a thin pole through the center hole of the blade. If the blade falls to one side, that side is heavier. Grind more steel on the heavy side to balance the blade. Don't grind more of the angle down, just grind a little steel off the back side or a corner of the blade. Once the blade is properly balanced, file (mill bastard file) off the burrs left behind by the grinder.

Mower shops will usually sharpen blades for a minimal cost if you don't feel comfortable grinding your own.