Here’s the best time to water your lawn according to the experts

With the ongoing heat waves we’re experiencing, it’s all too easy for your lawn to dry up and suffer. This can sometimes be the case even if you water it frequently, so what’s the problem here? The fact is, there’s a right and wrong time to water your lawn. Do it at the wrong time, and you’re just wasting water and encouraging disease, but do it at the right time, and your grass will thank you for it. 

Here, we take you through the dos and don’ts of watering your lawn, with a little help from the experts. We will explore when to do it, how often you should do it, and how much water you should use for the best effect. So you can get your grass thick and thriving again in no time. 

If you think your lawn is past the point of saving, be sure to check out how to revive dead grass.

When should you water your lawn? 

You can tell your lawn needs water when the grass loses its vibrancy in color. Tom Hilton, gardening specialist at National Greenhouse (opens in new tab) explains: “There’s two key indicators that your grass needs a little love, the first being the colour. If you notice an increase in brownish tones or a less glossy look to it, get the hosepipe out! Another little trick is to take note of how springy the grass is after being stepped on — if it stays down and doesn’t bounce back, this is another great indicator that it needs watering.”

The blades may also appear to ‘curl over’ at the ends when the grass is overly dry. You might also spot uneven brown or yellow patches of grass cropping up around your lawn — these areas could be getting less water than other sections. 

Dry grass with yellowing patches

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If you want to be sure of the moisture level of your lawn, you can try driving a screwdriver with a 6-inch shaft into the ground. If you struggle to push it in, then that means your lawn is dehydrated. 

The best time to water a lawn is actually in the early morning, ideally before 10am. This is because the temperature outside is still cool and the wind and sun are less intense, which gives the water a better chance to reach and penetrate your soil. This climate ultimately makes it less likely for the water to evaporate as soon as you apply it. 

Watering any later than this can be counterproductive. According to the landscaping experts at Toolstation (opens in new tab): ‘The main reason we wouldn’t advise watering in the middle of the day is because it’s less effective. During the hottest part of the day, lots of water will be lost to evaporation — a waste of both water and effort!’ 

Droplets of water on blades of grass

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There’s also the option of watering in the evening, which isn’t as wasteful, but it’s still not the best time. The experts at Toolstation continue: ‘Although it’s cooler at this time of day, if your grass is left covered in water droplets overnight, this can cause diseases like red thread and Fusarium.’

Diseases such as these are encouraged by excess moisture on your lawn during the cooler temperatures of the night. It’s a prime reason for watering your lawn in the morning versus the late evening. If you have no choice but to water your lawn later in the day, stick to between 4-6pm — this gives it a chance to dry out and recover before the sun sets.  

How often should you water and how much should you use? 

The answer to this question depends on a few factors. First, there’s the type of grass to consider and then there’s the age of the grass as well. On top of that, the type of soil you use contributes. 

There are two main types of grass: warm-season and cool-season. Warm-season can typically be found in the southern states, while cool-season tends to grow in the northern territory. If you’re unsure of which you have, you can always ask at your local home department store. 

A yard being watered by sprinklers

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With deeper roots, warm-season grass is more drought-resistant and so won’t need watering so often. With this type of grass, you could water it in two sessions over the week or do it in one day. Cool-season grasses will need a little more attention. More water is required and it’s better to break up the application into 2-3 sessions. 

In terms of the soil you’re using, keep in mind that clay soil retains water better than sandy soil, which drains more quickly. You may need to water less or more frequently depending on this. 

As a general rule, aim to apply 1-1.5-inches of water to your lawn a week, taking into account rainfall and humidity. It’s also better to break this down into sessions every 3-4 days, rather than daily or once a week if you can. That way, your lawn won’t be too dry or too wet on a regular basis. Bear in mind that your lawn will go dormant when the soil temperature drops through the colder months though. During this time, the grass can survive for weeks without water. Its color will return in the spring time. 

Holding grass seeds to plant

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However, if you’ve just planted grass seeds and your lawn is still young, you will need to be more resilient with watering it. At first, you will need to keep the bed moist (the top 1.5 inches of soil), but not saturated. That means you need to water it little and often — 1-2 times a day to start with for 5-10 minutes at a time, reducing this schedule once it reaches 1-2 inches in height. Growing grass takes a lot of maintenance, but once it’s matured it will require less effort.  

How can you tell if there’s enough, or too much, water? 

It’s all too easy to overcompensate for the heat and overwater your lawn. The trouble is, this is a wasteful habit which will cost you money, and it won’t be doing your lawn much good either. 

A tell-tale sign that you’ve overwatered is when you see water runoff the lawn, down the pavement and into the drain. At this point, the soil is no longer absorbing the water and it’s literally a waste of money. 

Water flowing into a drain next to a lawn

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If the ground feels overly muddy or spongy, then that’s another sign that you’ve applied too much water. An increase of weeds or thatch can indicate overwatering as well, as can fungal-growth, such as mushrooms.  

If you want to check that you’re using the right amount of water, there’s a couple of options. Tom Hilton recommends one such method: ‘Sprinklers can make this a much easier job, allowing you to get an accurate measurement of how much water you’re using by simply marking a container with an inch mark and seeing how long it takes to fill up. This will give you a great idea of how long to leave them on for, but obviously the traditional hose or even watering can methods are still effective.’ 

You can also check the soil regularly as it’s being watered using a screwdriver shaft. All you need to do is time how long it takes for the water to reach 6-inches deep. Once you have this time, you know how long to leave your irrigation system running in the future.

A sprinkler system watering the lawn

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You could also invest in a flow timer and calculate how much water you lawn requires. With this method you just multiply the square footage of your lawn by 0.62 gallons. The answer gives you the number of gallons you need to cover the entire lawn with 1-inch of water per square foot. We recommend the Orbit 21004 B-hyve Smart Hose Faucet Timer ($61.86, Amazon (opens in new tab)). 

Even if you follow the above guidance, you will need to keep a constant eye on your lawn’s condition. Regardless of whether you do everything right, the changing climate can still result in you over- or under-watering the lawn by accident. Always check its moisture level before you begin watering, and watch out for sudden heat waves drying it up faster than expected.


For more lawn tips, tricks, and how-tos, check out our guides on how to plant grass seed, how to make your grass greener, how to stripe your lawn, how to lay sod, 7 common lawn care mistakes you’re probably making right now and 7 ways to revive dead grass.    


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