Lawn mowing is a subject that’s full of dilemmas at this time of the year, but there’s one that’s got me scratching my head the most right now. How short should you cut your grass in a heatwave?
If your grass is in need of a good trim like mine is, it’s probably the first question on your mind as you look out at your garden this week. When I asked the experts for July lawn care tips, they said longer grass is preferable – but how short is too short? And when does a general mow become damaging?
I checked in with them again to find out how short you should cut your grass during this week’s heatwave.
What you'll need
Husqvarna Aspire LC34 P4A
With four cutting heights to choose from, the Husqvarna Aspire LC34 P4A is the best lawn mower we've tested so far.
Eufy E15 Robot Lawn Mower
The Eufy E15 has an impressive maximum cutting height of 75mm, which is ideal for summer mowing.
A wetting agent can give a dry, weather-worn lawn a hydrating boost.
If you’re looking for jobs to do in the garden during this July’s heatwave, it’s worth paying some attention to your lawn. While a normal mowing schedule can work, less is sometimes more.
‘Maintain regular mowing in July, as at this time of year, grass growth should be at its strongest,’ says Chris McIlroy, lawn expert at The Grass People. ‘You should aim for once or even twice a week, but still only remove the top third, as this promotes deeper root growth and builds resilience to the summer heat.’
The one-third rule seems to be the leading advice for mowing your lawn in hot weather; the longer the grass, the more sun protection for the lawn.
‘Longer grass blades help shade the soil surface, reducing evaporation and protecting roots from excessive heat,’ explains Cheryl Harper, managing director of Greensleeves Lawn Care.
A robot lawn mower is brilliant at cutting grass little and often, and you can even set mowing schedules for machines like the Eufy E15 (so it’ll do the hard work for you in the background!).
If the one-third rule is too vague a starting point, you can use a general cutting height guideline to work out how short to cut your grass in a heatwave instead.
‘For most domestic lawns, maintaining a height of around 4 - 5 cm provides a good balance between appearance and resilience,’ advises Cheryl.
There are a few other ways to protect your lawn in a heatwave, too.
‘Some tools can help speed up recovery and improve your lawn's chances,’ says Jonathan. ‘Aeration can improve water and nutrient absorption across the lawn, and a wetting agent can aid moisture penetration into the soil.’
So, best practice for mowing your lawn in a heatwave? Only remove one third at a time, and try to keep your grass at least 4 - 5 cm long. Putting up with longer grass will reward you with a healthier lawn come the end of summer!
