Reference
Recommended Mowing Height for Each Grass Type
The short answer
Set your mower by grass species, not habit. NC State Extension gives species-specific ranges: turf-type tall fescue performs best at 3 to 3.5 inches (never below 2.5), Kentucky bluegrass at 1.5 to 2.5 inches alone or 2.5 to 3.5 inches when mixed with tall fescue, and warm-season bermudagrass much lower at 0.75 to 1 inch with a reel mower (1 to 2 inches with a rotary mower).
The heights below all come from the one NC State source so the numbers are internally consistent rather than averaged across places. Cutting cool-season grass too short stresses it, thins the stand, and opens the door to weeds, which is why the low end of each range is a floor, not a goal.
Regardless of target height, obey the one-third rule: mow often enough that you remove less than one-third of the leaf blade at a time. To keep a 3-inch lawn, mow when it reaches about 4 to 4.5 inches.
Mowing height by species (NC State Extension)
Recommended mowing heights in inches, from NC State Extension's Carolina Lawns. Ranges reflect how each grass grows; where two figures appear for cool-season grasses, the higher one applies when the grass is grown in a mixture.
- Tall fescue: 3 to 3.5 inches; do not mow shorter than 2.5 inches.
- Kentucky bluegrass: 1.5 to 2.5 inches alone, or 2.5 to 3.5 inches when mixed with tall fescue.
- Fine fescue: 1.5 to 2.5 inches when mixed with Kentucky bluegrass, 2.5 inches or higher when mixed with tall fescue.
- Perennial ryegrass: 1.5 to 2.5 inches when mixed with Kentucky bluegrass.
- Bermudagrass: 0.75 to 1 inch with a reel mower, 1 to 2 inches with a rotary mower.
- Centipedegrass: mow when it reaches 1 inch, and no higher than 2 inches.
- St. Augustinegrass: 2.5 to 4 inches, mowed frequently during the growing season.
- Zoysiagrass: best cut with a reel mower; should not be mowed as short as fine-leaved cultivars are cut.
The one-third rule ties it all together
Pick your height from the table, then mow often enough to honor the one-third rule: NC State advises cutting frequently enough that less than one-third of the leaf surface is removed at any mowing. Scalping a tall lawn back down in a single pass shocks the plant, exposes soil, and invites weeds.
In practice that means mowing more often during fast spring and fall growth and less in summer dormancy. Raising the deck toward the top of your grass's range through summer also shades the soil and helps the lawn tolerate heat and drought.
→ These are the NC State recommendations; your regional Extension office may list slightly different ranges for the same grass under local conditions. Use the species range as a starting point, then adjust up in summer stress.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- NC State Extension - Carolina Lawns — Recommended mowing heights: tall fescue 3-3.5 in (not below 2.5); Kentucky bluegrass 1.5-2.5 in alone or 2.5-3.5 in with tall fescue; fine fescue 1.5-2.5 in with bluegrass, 2.5+ in with tall fescue; perennial ryegrass 1.5-2.5 in with bluegrass; bermudagrass 0.75-1 in reel or 1-2 in rotary; centipedegrass mow at 1 in and no higher than 2 in; St. Augustinegrass 2.5-4 in; turfgrass should be cut so that less than one-third of the leaf surface is removed at each mowing.