How short should you cut your grass? Mowing height guide
Choose a cutting height for your grass, then mow often enough to remove no more than one-third of its height at a time. A sharp blade and firm ground help produce an even cut.
What you need
Mower with a sharp blade, ruler, closed shoes and the protective equipment specified by the mower manufacturer.
Step by step
- Set the cutting height. Use the species table below as a starting point and refine it for your cultivar. On level ground, check the resulting cut with a ruler; numbered mower settings are not always inches or centimetres.
- Check whether a cut is due. Mow before the lawn grows more than about 1.5 times the target height. For a 3-inch (7.5 cm) target, cut by about 4½ inches (11 cm). If badly overgrown, remove only the top third and lower it gradually over later cuts.
- Clear and check the area. Remove stones, sticks, toys and hoses. Keep children, pets and bystanders away. Check slopes and obstacles before starting.
- Mow at a steady pace. Follow the mower’s slope and direction instructions. Overlap just enough to avoid missed strips and vary the mowing direction between visits. Avoid sharp turns that tear grass or repeated wheel tracks on soft ground.
- Leave short, evenly spread clippings. They return nutrients. If clippings form thick clumps, collect or spread them out so they do not cover the grass. An overgrown lawn may need collection during the first staged cuts.
- Check the finish. Look for missed strips, scalped high spots or ragged blade tips. Raise the deck where the ground is uneven. Ragged tips suggest a dull or damaged blade; stop the mower and isolate its power source before inspecting or clearing it.
- Clean and store. Follow the manual’s cleaning instructions with power isolated. Keep the blade sharp and inspect it after striking an object. Do not handle a blade while the mower can start.
After the job
Continue the usual watering and feeding plan; a normal mow does not require an extra fertilizer dose. If you scalped a patch, return to the suitable height and check soil moisture. Avoid another low cut.
For the final autumn cuts, stay within your grass’s normal range and prevent excessively long grass or leaves from matting. There is no universal 2-inch winter height.
New grass should be anchored before mowing, and the soil firm enough to walk on. Mow when it reaches about 1.5 times its intended cutting height. Keep turns gentle; a 4-inch first-mow rule does not suit every warm-season grass.
Starting heights for home lawns
These are broad ranges for common lawn types, not golf greens. Cultivar and mower type matter; follow local guidance for your variety. Hold cool-season grasses near the heat-stress height through the hottest weeks — the extra leaf area shades and cools the crown. The never below column is the point at which the remaining leaf area stops supporting the roots; warm-season grasses are the exception to “taller is better”, because stoloniferous species such as Bermuda thin and go woody if left tall. In shade, use a suitable shade-tolerant grass and generally the higher end of its range.
| Grass | Normal height | Heat-stress height | Never below |
|---|---|---|---|
| Kentucky bluegrass | 2.5–3.5 in (6–9 cm) | 3.5–4 in (9–10 cm) | 2 in (5 cm) |
| Tall fescue | 3–4 in (7.5–10 cm) | 4–4.5 in (10–11 cm) | 2.5 in (6 cm) |
| Fine fescue | 2.5–3.5 in (6–9 cm) | 3.5–4 in (9–10 cm) | 2 in (5 cm) |
| Perennial ryegrass | 2–3 in (5–7.5 cm) | 3–3.5 in (7.5–9 cm) | 1.5 in (4 cm) |
| Common Bermuda | 1–2 in (2.5–5 cm) | 1.5–2.5 in (4–6 cm) | 0.75 in (2 cm) |
| Zoysia | 1–2.5 in (2.5–6 cm) | 2–3 in (5–7.5 cm) | 1 in (2.5 cm) |
| St. Augustine | 2.5–4 in (6–10 cm) | 3.5–4 in (9–10 cm) | 2 in (5 cm) |
| Centipede | 1.5–2 in (4–5 cm) | 2–2.5 in (5–6 cm) | 1 in (2.5 cm) |
Some Bermuda, zoysia and dwarf St. Augustine cultivars need a different range. If unsure, start with grass identification rather than cutting lower.
Through the season, first mow to last
First mow of spring. Wait until the lawn is actively growing and has dried out from snowmelt or spring rain; mowing saturated soil compacts it and does more damage than another week of shagginess costs you. Set the deck to the low end of the normal range for the first cut or two to clear matted winter growth, then move back up.
Summer. Raise the deck to the heat-stress height for the hottest weeks. Taller grass shades the soil, keeps roots cooler and cuts evaporation, which lowers how often you need to run the sprinkler. It also shades out crabgrass and other sun-loving weed seedlings.
Last cuts before winter. Come down gradually over the final two or three cuts so the last mow sits roughly half an inch (1 cm) below the normal height for your species — not below the “never below” figure. Long grass mats under snow and invites snow mould. Do not scalp it: too little leaf area starves the crown of the reserves it needs to overwinter. There is no universal 2-inch winter height — work from your own species range.
Mowing new grass for the first time
New grass inverts the usual thinking: you are waiting for it to grow tall enough to survive a cut at all.
- Wait until it reaches about 3.5–4 in (9–10 cm) for cool-season seedlings, or about 1.5 times its intended height. Seedlings need that leaf area before their roots can anchor them against a mower pass. A 4-inch first-mow rule does not suit every warm-season grass.
- Check that the soil is dry enough to walk on without leaving footprints. Wet soil compacts under the mower and pulls shallow-rooted seedlings loose.
- Sharpen the blade before this pass. A dull blade yanks fragile seedlings out of soft soil instead of cutting them. See how to sharpen a mower blade.
- Walk gently and skip sharp turns on the new turf; the roots cannot yet resist twisting.
- Remove no more than one-third, as with any mow. Bring a shaggy first cut down over two passes a few days apart.
Mulch, bag or side-discharge?
For most mows, mulching wins by default. Clippings are roughly 80–85% water and settle into the canopy within days. Michigan State University Extension estimates that returned clippings supply on the order of 1 lb of nitrogen per 1,000 ft² (about 0.5 kg per 100 m²) over a season — enough to count in your feeding plan. The idea that clippings cause thatch is a myth extension agronomists have been correcting for decades: thatch builds from slow-to-decompose stems, crowns and roots, not from fast-rotting leaf blades. Collect or disperse clippings when they form thick clumps, when the lawn is badly overgrown, or when you are clearing diseased material.
Common questions
How often should I mow?
Mow according to growth. Cut before the grass exceeds about one-and-a-half times your chosen height, removing no more than one-third at once.
Should I collect all the clippings?
No. Leave short clippings that settle between the blades. Remove or disperse heavy clumps so they do not smother the lawn.
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