The lawn watering mistake that could kill your grass for good

You may think you’re doing the right thing by your grass, but watering it the wrong way could kill it.

Hot, isn’t it? And it’s not just us humans that are feeling the heat – our poor plants and lawns are likely to be suffering, too. It’s likely, whether you’re a keen gardener or not, that your first instinct will to be to go outside and water your drooping foliage and yellowing grass. But you could be making a big lawn watering mistake.

We spoke to Steve Morgan, gardens and outdoor manager at the National Trust’s Tredegar House in Newport, south Wales. Time and again, Morgan has seen well-meaning gardeners destroy their lawns by making a simple watering error. So before you grab your can or hose and give the grass a sprinkle, be sure not to make the same blunder.

Hosepipe watering gardenCredit: Ian Francis/Shutterstock

The lawn watering mistake too many people make

Are you watering for long enough?

Grass consists of up to 90% water, and when there’s a long spell of dry weather, it may start to appear less lush and green. But while you may think you’re doing right by your thirsty lawn by giving it the occasional drink, be careful not to go in for half measures.

“If you are going to water your lawn, you need to water it thoroughly,” warns Morgan. “That doesn’t mean sprinkling the top of it to make it damp, because that’s not going to help the lawn in any way, shape or form.

“You need to give it a good soaking so that you penetrate down to the root layer, especially if the ground has been drying out and hardening up for a while. In hot conditions, that means you are going to need to water it for quite some time.”


How long should I water my lawn for?

To give your lawn the thorough soaking it needs, you’re going to need to give it far more than a few minutes’ worth of water.

“For your average domestic lawn, I’d expect someone to spend at least 20 minutes and possibly up to 45 minutes watering the grass to make sure that water is getting to the roots where it’s needed,” advises Morgan.

How under-watering can kill your lawn

An all-or-nothing approach is best

Giving your grass some water – but not enough – can cause the blades to die back.

“What you don’t want is to just water just the top few millimetres of soil, because there is potential for the grass roots to turn up and grow towards that water,” Morgan explains. “What can then happen is that the roots get scorched off, and your grass will die. You’ll end up losing the lawn, when you thought you were giving it the best chance of survival.”

Morgan’s key takeaway? “Water thoroughly – otherwise it’s actually better not to water at all.”

Three more lawn watering tips

Follow this advice for a greener garden

Water butt with watering can at back of houseCredit: Lea Rae/Shutterstock

1. Use harvested rainwater if you can

Where possible, it’s best to use harvested rainwater on your lawn, rather than a sprinkler connected to the mains. This shouldn’t be a huge surprise, since rainwater is filtered naturally through the clouds, whereas treated mains water tends to be chlorinated.

According to the RHS, “Rainwater is better for your plants as it often has a lower pH. The minerals that are sometimes found in mains water, especially in hard water areas, can raise the pH of your root zone, which can affect the nutrient availability.”

“How can I give my lawn a good soaking from a static supply?” we hear you ask. Well, manufacturer Hozelock has created water butt pumps specifically for this purpose. Unfortunately though, for larger lawns, it’s likely you’ll need to use a combination of rainwater and mains water to deliver the volume of liquid your grass needs.

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2. Never water in the heat of the day

While you may think there’s nothing more refreshing that a cool drink in the midday sun, your lawn won’t agree. That’s because much of the water you apply will simply evaporate off the top of the soil as soon as it makes contact. It doesn’t stand a chance of getting down to the roots, where it’s needed.

In his guide to watering effectively for BBC Gardeners’ World, Alan Titchmarsh advises: “The best time of day to water? Best really in the evening. Then you know the sun is going down, and the evaporation won’t be quite so rapid.”

Sprinkler in garden at sunsetCredit: Connel/Shutterstock

3. If your lawn still goes brown, don’t panic

If you follow all our tips but your lawn still goes yellow or even brown, it’s not necessarily the end of the world (or your grass). Provided the lawn is well established and has a healthy root system, this change of colour should be nothing to worry about.

“Even well-kept lawns tend to go brown in hot summers,’ says Mick Lavelle, a senior lecturer in horticulture at Writtle University College. “If this does occur, fear not; your lawn is just resting and will green up once autumn rains arrive.”

Amy Cutmore

Written by Amy Cutmore she/her


Amy Cutmore has been writing about interiors for more than 20 years, harking back to the days when glossy red kitchens, toile de Jouy and rag rugs were all the rage, and everyone wanted a Changing Rooms makeover. You’ll have seen Amy’s work at Britain’s biggest homes titles, including Ideal Home, where she served as Consumer, Technology and Group Digital Editor. She has also edited or written for Homes & Gardens, Livingetc, 25 Beautiful Homes, Real Homes, Gardeningetc, Inside Readers’ Homes, Inspirations for Your Home, Country House & Home, Top Ten Reviews, Trusted Reviews and Country Life.

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