Ways To Water Your Garden During A Heatwave 

We think that 2026 could well be remembered for its intense, record-breaking heatwaves across the UK, with the first one in May when the temperatures reached 35.1 degrees Celsius at Kew Gardens, London, and the second in June when a new provisional UK maximum temperature of 37.7 degrees Celsius was recorded at Linwood, Norfolk. 

With July now seeing the arrival of heatwave number three, we decided it was time to share with you some of the questions we’ve been asked by gardeners as they try to keep their plants thriving and their gardens vibrant amid soaring temperatures.

Hopefully, our answers will help you to maintain your gardens easily and efficiently!

How often should I water plants in a heatwave?

One of the questions we're asked most often is 'How often should I water my plants during a heatwave?" The truth is, there is no 'one size fits all' approach.  The ideal watering schedule depends on several factors, including the types of plants you're growing, their location, and your soil conditions. 

We recommend checking the moisture level of the soil.  A simple way to do this is by pushing your finger into the soil or using a trowel to gently expose the soil beneath the surface.  Ideally, check the moisture down to down to around 15cm (6 inches), where many plant roots are actively growing.   

If you prefer a more accurate and convenient method, soil moisture sensors can be inserted into the ground to measure moisture levels without the guesswork-or the muddy hands!

For gardeners using automatic irrigation systems, watering times are easy to programme, but watering only when it's actually needed is even better. Many leading irrigation manufacturers now offer smart sensors that connect to compatible watering controllers. These sensors monitor the moisture and automatically delay watering when it is not required, helping to keep plants healthy while preventing unnecessary water use.

So our answer is basically, let the soil tell you if it’s time to water! That way, you shouldn’t waste water and will keep your plants growing strongly. 

When to water plants in a heatwave in the UK?

When to water plants on a hot day is often asked, along with whether it’s safe to water them in hot weather. So, let’s take a look at the best time to water your garden and why timing is critical if you want to water wisely and ensure your plants get the most moisture, rather than having lots of it quickly lost to evaporation. 

During a heatwave, the hottest part of the day is typically between 3:00pm and 5:00pm, while the sun's rays are at their most intense between 11:00am and 3:00pm. This makes the middle of the day the least suitable time for watering, as much of the water can be lost through evaporation before it reaches the plant roots.

Although watering before 11:00am is preferable, temperatures begin to rise noticeably from around 9:00am, reducing the effectiveness of watering as the morning progresses. For the best results, we recommend watering before 9:00am.

Watering early in the morning gives moisture time to soak deeply into the soil, allowing plant roots to absorb the water before the day's heat arrives. This helps plants stay hydrated, reduces the risk of heat stress, and can prevent leaves from drooping or wilting during the hottest part of the day.

The ideal watering window is between 6:00am and 9:00am. If you have an automatic irrigation system with a timer, you can programme it to water during these early hours, ensuring your plants receive the moisture they need while you're still asleep or away from home.

Although early morning is the ideal time to water your plants, watering later in the day won't harm your plants if they urgently need it. During the hottest part of the day, more water is lost through evaporation, and plants are generally less efficient at absorbing moisture. However, if your plants are showing signs of severe dehydration or wilting, watering them at midday can still help prevent them from collapsing.

If you do need to water during the hottest part of the day, apply the water directly to the soil around the base of the plant rather than wetting the leaves. This ensures more water reaches the roots, where it's needed most, instead of being lost through evaporation.

It's also important to water deeply rather than lightly. A thorough soak allows the water to penetrate into the root zone, encouraging stronger root growth and providing lasting moisture, rather than leaving water sitting on the soil surface where it can quickly evaporate.

What’s the best way to water my plants during a heatwave?

Whether you're using a watering can, a hosepipe with a spray gun, a drip irrigation system, or a porous soaker hose, the most important principle is to water deeply rather than little and often. Deep watering encourages plants to develop stronger, deeper root systems, making them more resilient during periods of hot, dry weather.

Deep watering can certainly be done by hand with a watering can or hosepipe, but it requires time and patience.  Apply the water slowly and directly to the soil around the base of each plant, avoiding the foliage wherever possible. A gentle flow allows water to soak into the ground rather than run off the surface, so you may need to spend several minutes watering each plant to ensure sufficient moisture reaches the root zone.

For a more efficient and consistent approach, consider using an automatic irrigation system that delivers water slowly and precisely where it's needed. Drip irrigation systems, dripline tubing and soaker hoses are all excellent options, as they apply water directly to the soil around your plants, minimising evaporation, reducing water waste, and ensuring moisture reaches the roots effectively.

Drip Watering Systems

Drip watering systems are designed to deliver water at lower pressure directly to the base of your plants, allowing it to soak into the soil and reach the roots, reducing evaporation and minimising waste. A bonus of using drip irrigation systems is that when used with pressure reducers and a water timer, they are normally exempt from hosepipe bans because they are so water-efficient. 

Drip Line

An easy-to-install PC Drip Line system, with pre-installed drippers along its length, evenly releases water along its entire length when laid in densely planted flower beds or vegetable gardens. As it slowly drips onto the soil surface, it quickly soaks in, reaching the roots of your plants. 

Soaker Hose

Made from porous material, which gently weeps water directly onto the surface of the soil, ensures minimal wastage. Simple starter kits provide you with everything you need to attach the hose to an outside tap and position the flexible hose around your plants in garden beds or borders.  

A Few Top Tips For Caring For Your Garden During A Heatwave 

So, with lots of information now at your fingertips as to how to water your plants during a heatwave, we thought we’d finish with a few tips we’ve picked up over the years, which will help your garden to stay vibrant in even the hottest weather. 

Mulch Once To Lock In Moisture Every Time You Water

Just a 5 to 7cm deep layer of mulch on top of your garden beds and borders will both protect your plants' roots from extreme temperatures, as it forms a physical barrier against direct sun and drying winds, and at the same time, it helps lock moisture into the soil so it isn’t lost to evaporation. If you are using a drip tube to automatically water your plants, this can be buried in the mulch, hiding the tube and protecting it from UV rays whilst minimising evaporation. 

Group Together To Provide Shade 

Any plants growing in pots and planters around your garden will quickly run out of moisture during a heatwave. Where possible, move them so they are grouped together to a shadier area within your garden. By grouping plants together, you will also increase air humidity through transpiration, as the moisture they release through their foliage becomes shared humidity. When you have small pots, you can even place them on pebble trays to increase humidity.  

Don’t Panic If You See Plants Wilting 

Whilst it might seem alarming when plants droop or wilt in the middle of the day, this is usually just their way of surviving high temperatures. If you are concerned, simply check the moisture in the soil - you often find it's still moist, and this means that your plant is only temporarily wilting to slow water loss down and reduce its exposure to the sun. As soon as temperatures cool in the evening, your plants should start to recover. 

Hopefully, our advice will help you worry less about your garden during extreme temperatures and enable you to water your plants correctly so they thrive all summer long.

Happy Gardening! 🪴