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Don’t mow the lawn: Expert advises on how to protect your grass during a heatwave

Contributor
By Contributor
July 1st, 2025

This summer will see temperatures reach above 30 degrees in parts of Canada — and while it might seem the perfect time to cut your grass, mowing your lawn in the heat can cause serious damage.

According to Homestars.com, the reliable way to hire a pro, residents should leave mowing the lawn until the weather has cooled. Mowing in the heat can damage or even kill the blades, leading to ugly brown patches in the grass. On top of this, doing yardwork in extreme temperatures could lead to heat exhaustion or sun stroke. Leaving the lawn to grow during the heat protects the blade and the soil from the penetrating rays of the sun — but if you really can’t bear to leave it, there are some important tips to follow.

Colleen McGrory, from Homestars.com, says: “While the warm weather might seem like a great opportunity to make your garden look neat and tidy, gardening in the heat can actually be a bad idea.

“High temperatures and strong sun exposure can damage plants — and that includes grass blades. If you cut your grass, the blades will be more exposed to the sun, and the soil will also suffer. This issue will lead to bare patches on your lawn which will take time and effort to repair.

“Extra length in your grass will protect it until the worst of the heat is over. There are other ways to help protect your lawn in extreme temperatures too.”

Here are Homestars.com’s dos and don’t for looking after your lawn (and yourself) during a heatwave:

DO:

Reduce foot traffic when you can

While you’ll want to enjoy your yard in the nice weather, be mindful of heavy foot traffic on your grass. Walking on your lawn will stress it, which can cause further damage during heatwave, and can cause soil compaction. The risk? Water won’t reach the grassroots of your lawn.

Let it grow

Letting your grass grow a little longer allows it to cope with heat stress. Longer grass in hot weather acts as a “micro jungle,” with taller stems helping to sustain a microclimate at soil level. Keeping your lawn length to around 2.5cm to 5cm is recommended. Even twice that height can promote healthy blades of grass.

Raise your mower

To avoid scalping the lawn, the cutting height of your mower should be increased during dry conditions. The majority of lawn mowers have different height settings. A higher setting will allow valuable moisture to be trapped, limiting evaporation and encouraging stronger, deeper roots to grow, which improves drought tolerance overall. Leave the clippings on the lawn as mulch, which will help to retain moisture and add nutrients.

Create a wild yard

Wild yards with native plants are better at coping with drought. You’ll need to water them less and will have a bit more green. You’ll also supply a rich nectar source for bugs and pollinators, in turn helping the environment.

Be prepared to water

If you need to mow your lawn when it’s hot, be prepared to regularly water it with about one inch of water per week, using a sprinkler, watering can, irrigation system or garden hose. If using a sprinkler, it will take approximately 30 minutes to get a half inch of water. However, make sure not to overwater; daily watering may not be needed.

Provide shade

Shade helps to lower water loss through evaporation, which in turn creates a cooler microclimate, reducing the need for frequent watering while maintaining grass health and providing much-needed relief for your lawn. There are many different options to add shade to your yard including awnings, parasols, sail canopies, pergolas, arbours or gazebos, as well as planting trees or tall shrubs. The best option for you will depend on your yard size, type and the budget you have available.

DON’T: 

Panic

While a damaged lawn during a heatwave is understandably stressful, it is rarely irreversible! Your lawn will likely recover once rainfall happens, which may happen in parts of Canada soon.

Get heatstroke

Mowing a large lawn in extreme heat  is exhausting work, and could even lead to heat exhaustion or heat stroke. Avoid it if you can, and, if you’re unable to avoid mowing or gardening in hot weather, ensure you apply sunscreen, wear a hat and take regular breaks to drink water.

Water your lawn when it’s sunny

Watering your lawn in hot, direct sunlight can cause damage. Instead, water during the cooler parts of the day — either early morning before 8am or at night after 9pm — when grass can take in the water and without losing it to evaporation. If you’re using a sprinkler with a timer, set it for one of those windows.

Waste water

A great tip is to use “grey water” for irrigation, which means repurposing water from activities like vegetable boiling or bathing to conserve water resources. Adding a rain barrel or collector is another great way to save water and reduce your impact on the environment. However, ensure that the water does not contain harsh chemicals, as you want to maintain the health of your grass and soil.

Forget to reseed

It’s crucial that you re-seed to fill in bare spots on your lawn, as this process will help to reduce water loss and soil erosion. The ideal times to seed lawns are in spring from March to early May, and then late summer from the end of August into September.

If you’re looking for a reliable pro to help you take care of your lawn during a heatwave, quickly find available contractors at: https://www.homestars.com/gardening-outdoors/landscaping-company-pros

Categories: EnvironmentGeneral