How high to mow your lawn
Mowing heights by grass type, and the one-third rule
Taller is usually better
Grass cut at the right height roots deeper, copes better with heat and drought, and crowds out weeds. Mowing too low restricts roots and invites weeds; in tall fescue lawns, the right height alone can cut weeds and disease by half or more.
Heights by grass type
Keep your grass within its range.
- Tall fescue: 3–4 inches (7.5–10 cm).
- Kentucky bluegrass and fine fescues: 2.5–3.5 inches (6.5–9 cm).
- Perennial ryegrass: 2–3 inches (5–7.5 cm).
- Bermudagrass: 1–2 inches (2.5–5 cm); hybrids 1–1.5 inches (2.5–4 cm).
- Zoysiagrass: 1.5–2.5 inches (4–6.5 cm); fine-bladed kinds 1–2 inches (2.5–5 cm).
- St. Augustinegrass: 3.5–4 inches (9–10 cm); dwarf kinds 2.5 inches (6.5 cm).
- Centipedegrass: 1.5–2 inches (4–5 cm).
- Buffalograss: 2–3 inches (5–7.5 cm), or leave it unmowed.
The one-third rule
Never remove more than a third of the grass blade in one mowing. To keep a lawn at 3 inches (7.5 cm), mow before it passes about 4.5 inches (11.5 cm). If it got away from you, bring it down gradually over a few mowings.
Mow smarter
Small habits make a healthier lawn.
- Keep blades sharp. Dull blades leave a frayed, brown-tipped look.
- Leave the clippings. They don't cause thatch, and they can cut the lawn's feeding needs by up to half.
- Sharpen the blade after about 10 hours of mowing, and change direction each time you mow.
- Mow shaded areas 0.5–1 inch (1.3–2.5 cm) higher.
- Some experts raise cool-season lawns to the top of their range in summer heat; others keep one height all year.
- Mow only when the grass is dry, after the dew has burned off.
Mow safely
Read your mower's manual. Pick up stones, sticks and other debris first, wear sturdy shoes and eye and ear protection, and keep kids and pets out of the yard while you mow. Never refuel a hot engine, and turn the mower off before you touch the blade or do any maintenance.
Sources
- University of Maryland Extension: Maintaining an Established Lawn
- Texas A&M AgriLife Extension: Mowing Recommendations for Warm-Season Turfgrasses
- Purdue Extension: AY-8: Mowing, Dethatching, Aerifying and Rolling Turf
- UF/IFAS Extension: Mowing Your Florida Lawn
General guidance, not a diagnosis. Written by PlantWiz in our own words from the sources above.