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Of all the things that affect your lawn’s health, mowing height is probably the most overlooked. Most people set their mower once and never think about it again. But cutting at the wrong height – particularly cutting too short – causes more lawn problems than almost anything else.
Get this one thing right and everything else becomes easier. Get it wrong and you’ll be fighting problems all year.
Why Mowing Height Matters
Grass is a plant, and like all plants, it needs leaves to photosynthesise. Cut those leaves too short and the plant can’t produce enough energy to maintain healthy roots, fight off disease, or recover from stress.
Here’s what happens when you cut too short:
X Roots become shallow (less drought tolerance)
X Grass weakens and thins out
X Weeds get more light and space to establish
X Moss moves in to fill gaps
X The lawn scalps on uneven ground
X Stress damage from heat and drought increases
And here’s what happens when you maintain the correct height:
– Deeper roots that access water and nutrients
– Thicker growth that crowds out weeds naturally
– Better drought tolerance
– Healthier, greener appearance
– Less stress from heat and cold
The Right Mowing Height for UK Lawns
For most UK lawns, the ideal mowing height is between 2.5cm and 4cm (1-1.5 inches). But within that range, the best height depends on the season, grass type, and conditions.
Seasonal Mowing Heights
Spring (March-May): Start at 4cm for the first few cuts, then gradually lower to 3-3.5cm as growth accelerates. Never remove more than one-third of the blade length in a single cut.
Summer (June-August): Maintain 3-4cm in normal conditions. Raise to 4-5cm during hot, dry spells – longer grass shades the soil and retains moisture better.
Autumn (September-November): Keep at 3-4cm through September and October. Raise to 4cm for the final cuts as growth slows.
Winter (December-February): Minimal mowing needed. If you do mow during mild spells, keep it at 4cm or higher. Longer grass is more resilient to frost and winter stress.
Grass Type Considerations
Different grass types have different ideal heights:
Standard utility lawns (most UK gardens): 3-4cm
Fine ornamental lawns (luxury grass): 2-2.5cm
Shaded areas: 4-5cm (longer blades capture more light)
High-traffic areas: 3.5-4cm (more leaf = faster recovery)
The One-Third Rule
Never remove more than one-third of the grass blade length in a single cut. This is the single most important mowing rule.
If your grass is 6cm tall, don’t cut it below 4cm. If it’s grown to 9cm while you were on holiday, bring it down in stages over several cuts rather than scalping it in one go.
Removing too much at once shocks the plant, weakens the roots, and can cause browning. It’s better to mow more frequently at the right height than to let it grow long and then cut it short.
What Happens When You Cut Too Short
Cutting too short – often called “scalping” – is the most common mowing mistake. It happens when people set their mower as low as it goes, thinking shorter grass looks neater or needs mowing less often.
The reality is the opposite. Scalped grass:
– Grows back faster (stress response) so needs more frequent cutting
– Develops shallow roots that dry out quickly
– Turns yellow or brown from sun damage
– Creates bare patches where weeds and moss establish
– Looks worse, not better
If your lawn is yellowing after mowing, or you can see soil through the grass, you’re cutting too short.
Adjusting for Conditions
Smart mowing means adjusting your height based on what’s happening with the weather and your lawn.
During Drought
Raise the mowing height to 4-5cm. Longer grass:
– Shades the soil, reducing evaporation
– Develops deeper roots seeking moisture
– Stays greener longer without constant watering
If drought is severe, stop mowing altogether and let the grass go dormant. It will recover when rain returns.
In Shade
Raise the height to 4-5cm in shaded areas. Grass in shade needs every bit of leaf surface to capture available light. Cutting shaded grass short is a recipe for thin, mossy patches.
After Renovation
When you’ve scarified or overseeded, wait until new grass is at least 5cm tall before the first mow. Then cut at 4cm – higher than normal – to avoid stressing young plants. Gradually lower to your normal height over several cuts.
Before Winter
Raise the height for the final mow of the year. Grass going into winter at 4cm is more resilient to frost, disease, and waterlogging than grass cut short.
How to Measure Mowing Height
Most mower height settings are just numbers (1, 2, 3, etc.) that don’t correspond to actual centimetres. To check your real cutting height:
1. Set your mower on a flat, hard surface
2. Measure from the ground to the bottom of the cutting blade
3. That’s your actual cutting height
Do this for each setting so you know what you’re actually cutting at. You might be surprised – many mowers cut shorter than their settings suggest.
Other Mowing Best Practices
Keep blades sharp. Blunt blades tear grass rather than cutting cleanly, leaving ragged edges that turn brown and invite disease. Sharpen or replace blades at least once a season.
Mow when dry. Wet grass clumps, cuts unevenly, and can spread disease. Wait for the lawn to dry after rain or heavy dew.
Vary your pattern. Mowing in the same direction every time causes grass to lean one way and can create ruts. Alternate between different directions.
Leave clippings. Short clippings decompose quickly and return nutrients to the soil. Only collect clippings if they’re long enough to clump and smother the grass.
For more guides on mowing and all aspects of lawn maintenance, visit our complete lawn care resource.
Frequently Asked Questions
How short should I cut my lawn?
For most UK lawns, 3-4cm is ideal. Never go below 2.5cm for standard grass types. Fine ornamental lawns can be cut to 2-2.5cm, but this requires more frequent mowing and careful maintenance.
How often should I mow?
During peak growth (late spring to early summer), weekly or even twice weekly. In cooler months, every 10-14 days. The goal is to never remove more than one-third of the blade length, so mow more often rather than cutting more off.
Should I cut grass shorter before winter?
No – the opposite. Raise your cutting height for the final mow. Longer grass (around 4cm) survives winter better than short grass. It’s more resistant to frost damage and provides better protection for the crown of the plant.
Why does my lawn turn yellow after mowing?
You’re cutting too short. When you remove too much leaf, you expose the pale lower stem and stress the plant. Raise your mowing height and follow the one-third rule.
Is it better to mow little and often?
Yes. Frequent light cuts at the correct height produce healthier grass than infrequent heavy cuts. The grass experiences less stress and maintains better root depth.
Proper mowing keeps your lawn healthy – but it still needs the right nutrients at the right time. Our Year Round Lawn Treatment Bundle gives your grass everything it needs through every season.
