Free lessonLawn care through the year · lesson 2 of 10

Mowing well

How high to cut, how often, the one-third rule, and what to do with the clippings.

Key points

HeightSummer: 13–25 mm for an everyday lawn, 6–13 mm for a fine lawn. Spring and autumn: up to 40 mm. Higher in shade and drought.

How oftenWeekly in summer, every week or two in spring and autumn, rarely in winter; never on frozen or soggy grass.

One-third ruleNever cut off more than a third of the height at once; lower the blades gradually.

ClippingsCollect and compost in thin layers, or mulch if you cut little and often.

EdgesTrim with long-handled edging shears after mowing; recut a crisp edge with a half-moon iron in spring.

Summary

When	Height	How often
Spring	Up to 40 mm, lowering gradually	Every week or two
Summer	13–25 mm (higher in drought)	Weekly
Autumn	Up to 40 mm	Every week or two
Winter	High setting, mild spells only	Rarely

Quick check

How much of the grass height should you take off in one cut?

About half, to save mowing time
Whatever reaches the summer height
Two thirds, then rest it a fortnight
No more than a third

Answer: D. Harder cuts shock the grass and let moss and weeds in.

What height suits an everyday lawn in spring and autumn?

Up to about 4 cm
About 6 mm, as for a bowling green
About 1 cm, the summer minimum
As short as the mower will go

Answer: A. Slow-growing grass needs its leaves.

What should you do with the mower in a dry spell?

Lower the blades so the grass uses less water
Mow more often to keep the brown tips tidy
Raise the blades and mow less often
Collect and remove every last clipping

Answer: C. Longer grass shades the soil and roots deeper.

In your garden

Set the mower height for the season.
Sharpen or replace a blunt blade: torn tips go brown.
Next time you mow, take off no more than a third.

Video transcript

Mowing is the job you'll do most, and doing it well makes more difference than any product. In this lesson: how high to cut, how often, the one third rule, and what to do with the clippings.

In summer, cut an everyday lawn to between about one and two and a half centimetres, and a fine lawn shorter. In spring and autumn, leave it longer, up to about four centimetres, because the grass is growing more slowly and needs its leaves. Leave it longer in shade and in dry spells too. Longer grass grows deeper roots.

Mow from March to October. In summer, when grass grows fastest, once a week is about right. In spring and autumn, every week or two. In winter you rarely need to mow at all, but in a mild spell you can top it on a high setting, as long as the ground is firm and not frozen.

The golden rule: never take off more than one third of the grass height in one cut. Cutting harder than that shocks the grass, turns it yellow and lets moss and weeds in. So in spring, start high and lower the blades gradually over several cuts. If the grass has grown long, cut it on a high setting first, then lower it a week later.

Collect the clippings for a neat finish and less thatch at the base of the grass, and add them to the compost heap in thin layers, mixed with other material. Or use a mulching mower, which chops the clippings fine and drops them back to feed the lawn. Leaving clippings works best in dry weather and when you cut little and often, so they don't lie in clumps and smother the grass.

This is one of 10 lessons in Lawn care through the year

The full course adds sorting drills, flashcards and a printable summary sheet for every lesson.