Caring for your lawn in hot weather

The UK is in the throes of a heatwave and lawns everywhere are suffering.  In this blog we ask “what is the best way to care for your lawn in hot weather?”

Grass is incredibly resilient. In fact I can’t think of any other plant that we expect (and get) so much from. Lawn grasses are long lived, frost hardy, tolerant of close mowing, robust enough to walk on – a lot – and still look good all year round. Could you say the same for flowers or vegetables plants?

So given that your lawn does all that whilst absorbing greenhouse gasses and providing you with oxygen, it’s only fair that you give it some TLC in return isn’t it?

During hot weather, your grass will be under a lot of stress. It will lose water from its leaves in a process called transpiration. Now transpiration is great for people, it’s what makes a natural grass lawn cool to sit on and it’s why a garden with a lush green lawn feels luxuriously fresh on a hot day.

Transpiration cools the plant but it does involve water exiting the leaves. That’s fine, provided that the plant can replace that lost water by sucking more up through its roots. When the soil is really dry, the plant can’t rehydrate itself and that’s when it goes into survival mode.

Lawns and drought

When your lawn runs out of soil water it will go into survival mode. Any water and nutrients being held in the leaves will be moved and stored in the roots. Roots are underground where the temperature is cooler and there are no drying winds. Sensible move I hear you say. I do the same thing in the house – any food that is vaguely perishable gets put in the fridge.

A large lawn in very dry weather. It’s not unusual for different grass species to react slightly differently to drought. Fescue grasses and bent grasses tend to turn brown sooner than the deeper-rooting ryegrasses. The clover in the foreground seems to be doing OK too. Dry weather will reveal many of your lawn’s hidden secrets!

What that means is that your lawn in hot weather, will lose its green colour and its lovely texture to become brown, strawlike and well, parched.

At this point you have two choices. You can either water your lawn, or you can work with nature and adapt your lawncare regime accordingly.

I’m not even going to discuss the first choice. Water is a scarce resource and as the UK population rises its more and more difficult for water companies to keep up with the job of cleaning and distributing our water. When there’s a drought, mains water should be used for health, hygiene and food production. Lawns are beautiful, I love them very much, but I know that a brown lawn will recover when it rains so I’m saving mains water for my early morning cuppa.

I won’t be watering my lawn in hot weather.

That just leaves plan B.

How to care for your lawn in hot weather or drought

1. Keep off the grass as much as possible. I know it’s not always possible but if you can reduce the amount of wear and tear (stress) on your lawn, please do. That means not leaving toys and furniture in one place for more than 48 hours. Move stuff around. Encourage children and dogs to enjoy the weather without running around. And if you need to walk over the lawn to get to the shed/chicken run/washing line, try to take a different route each time.
2. You probably won’t need to mow the lawn. But if you do, keep the mower blades as high as possible and as sharp as possible. Longer grass shades the soil beneath it and slows down moisture loss. It creates a microclimate, a bit like a very small jungle.
3. If you do mow the lawn, let the clippings drop back into the sward rather than collect them in the grass box. They’ll form a mini-mulch, similar to the layer of bark chips that you spread beneath shrubs to conserve soil moisture.
4. Hold back on all lawn treatments. No feeding and no weedkilling. At least not until it’s rained enough to turn the grass back to green again.
5. Once the rain has come and your lawn is looking green, plan your autumn renovations. Aeration, scarification and topdressing will all help improve the soil beneath your lawn so that it retains water for longer next time there’s a drought.

Looking after newly laid turf in a drought

Newly laid turf needs much more TLC than an established lawn because it doesn’t have a strong enough root system to support the plants’ survival mode.

If you can delay turfing until the drought has passed, please do so. If not, then you need to be super-vigilant over watering.

If its essential that you lay your new lawn in hot weather, add some water retaining gel crystals to the soil before you lay your turf. It will help you to ensure that as little water as possible is lost to evaporation.

Water in the early morning or late evening – both if you need to. When the sun is lower in the sky water has more chance of sinking into the soil before it evaporates away in the heat of the sun.

If your area is subject to a hosepipe ban, talk to your water authority. You may be able to get a temporary exemption. If not, you’ll be getting lots of exercise as you irrigate your new turf with a watering can!

In short. Brown lawns are still beautiful. They’re not dead, they’re doing clever stuff to ensure their survival. The best way to help them is to keep calm and wait for the rain.

More articles on summer lawn care

Why a natural lawn is better than artificial turf – whatever the weather

Hints and tips on summer lawn care