The South West London Gardener

7 Tips on Keeping your Garden Healthy in a Heatwave


On the 28th July, 2019, a record was broken in the UK.

In the delightful Cambridge botanic gardens, a temperature of 38.7 degrees Celsius was recorded.

This was the hottest UK temperature ever recorded, and as I write this in 2022, there’s a 30% chance of that being broken in the coming week.

So, with temperatures reaching all new highs, and seemingly increasing year on year, just how can you keep your garden healthy.

Well, at The Southwest London Gardener, we love to help keep your gardens healthy and in bloom, and that is why we have compiled a list of seven ways to care for your garden in extreme heat.

Let’s take a look.

How to Help your Garden Survive in Extreme Heat

1. Get to Work Early

The first thing to do when expecting a heatwave is set your alarm.

As soon as the sun peeks out in the morning, the temperature is on the rise, so the earlier you can get out the better.

Try and avoid working in your garden at times of peak heat such as midday and early afternoon. This won’t be good for you or your garden.

When watering your plants, the morning is the best time of day. This is because water needs time to soak into your soil, and if you’re providing it when it is really hot, a lot of this can be lost to evaporation before the plant gets to take it all in.

Another good reason for this is that in extreme heat, plants get thirsty. From the moment the sun is up, the water from yesterday may be already gone, so they will be ready for some more. The earlier you can give this to them so they can prepare for the day ahead the better.

There are plenty of other benefits as well, including avoiding scorched leaves and keeping away pests that would thrive on moist soil overnight.

2. Give Your Plants Some Protection

Just like us humans, plants need some protection from the sun.

Unfortunately, covering them in sun cream won’t have the same effect, so you need to think of other ways to keep them in the shade, such as using shade cloths that can stop the sun from directly hitting your plant but help to maintain a good level of aeration.

We’ve mentioned mulch before in our blog, and we’re going to do it again as it can be a real life-saver when it comes to your plants.

What mulch does is provide a layer of protection for your plants. This means that as the sun beats down, the soil and the roots underneath the mulch have something in between them and the direct sun which helps to keep them cool.

This can provide a big boost in keeping your plants thriving in a heatwave.

And if you want to be really careful, try and opt for a light-coloured mulch that will reflect the heat away, things like light-coloured wood chips or straw make a great choice here.

3. Keep an Eye on New Plants

Plants are most vulnerable when they are freshly planted, so if you are deciding on adding some new bursts of colour to your garden with some new flowers then make sure you plant them at the right time.

On the evening is the perfect time to do this as they can then have the night to acclimatise while the weather is slightly cooler than it will be during the day.

Stick to the measures listed above to stop new plants from being impacted directly from the sun when it is at its peak temperature and keep a closer eye on your new blooms than you would on plants that are already well established.

Add plenty of mulch to the soil surrounding the roots (half potting mix and half mulch is a good formula) and if you see a cloudy day on the horizon, maybe hold off until it arrives to give your new flowers the best chance of a strong bloom.

If you’re planting in a pot that can be moved, placing it in the shade is always a great choice when the weather gets too hot.

4. Keep Your Lawn Long

If you step outside on a hot day, you can often hear the buzzing of distant lawnmowers as they get to work cutting your neighbour’s grass.

But having short grass in a heatwave could actually do more damage than it does good.

In fact, longer blades of grass do a much better job at providing a spot of shade for the soil it is growing in. This can make a real difference when helping the soil to retain moisture and to stop it from scorching.

If you have ever seen the light brown patches of short, burnt, grass on some lawns, this is because it has been cut too short and it doesn’t have the tools to fight off the heat of the sun.

Of course, this isn’t the only thing you can do to help your lawn. You must keep it moist, and the rule of giving it a sprinkle a few mornings every week to provide some water is vital. You should also aerate it so the soil doesn’t get too compact.

This isn’t to say don’t mow your lawn.

You can still keep it neat and tidy, but opt for the highest setting when choosing to give it a trim, and try to avoid going lower than 6cm long.

5. Don’t Panic and Overdo It

It is easy to panic when you hear of temperatures in the 30s and think your garden won’t be able to handle it.

The first thing you need to do is not worry.

Nature is resilient.

Your garden will survive, so don’t overdo it.

If your first thought is to flood your garden with water, then you will probably be doing more harm than good.

If you overwater, even in hot temperatures, you run the risk of drowning your plants. The roots of your plants pick up oxygen from small pockets of space in between the soil. If the soil is too dense and has been watered too much, these spaces quickly close up and can leave your plants struggling to get the oxygen it needs.

If you’re taking a walk across your grass and noticing it is bubbling underfoot, then this is a sign you are overdoing it.

This can stop your grass from growing to its full extent.

You don’t even have to water every day, with three times a week sometimes sufficient.

6. Provide Help for the Wildlife

It’s not only your plants that struggle in this heat but also the wildlife that visits it.

If you have a natural garden and provide plenty of shelter and food for the birds, hedgehogs, insects, and more that like to pop in and say hello, then this is even more important to maintain during a heatwave.

In extreme temperatures, animals are just like us humans, and most will be desperate for a spot of shade, so use up some of the twigs and leaves that are lingering in your garden waste bin and provide a spot for them to relax out of the sun.

The main thing that these animals will need is water.

If you regularly get birds paying a visit, make sure their water is well topped up throughout the day, even if this requires filling it several times due to evaporation.

And of course, if you have pets such as dogs and cats, try and provide a spot of shade for them to relax in so they’re not directly in the sun. Dogs for example often enjoy laying in the sun, but too much of this can be damaging for their health, so keep an eye on them and provide everything the wildlife in your garden needs to stay fit and healthy in the extreme heat.

7. Look After Yourself

The final tip on caring for your garden, is to care for yourself.

Your garden needs you over the days of high temperatures, so by protecting yourself, you can help to protect it.

Remember to try and perform your more strenuous tasks in the morning when it is cooler and the sun isn’t directly in the middle of the sky.

This will mean it won’t tire you too much and you will have less of a risk of sun stroke or burns.

Keep hydrated.

This is absolutely vital. We know how physically demanding gardening can be, so don’t forget to keep sipping away at your water.

It is recommended to drink one cup (eight ounces) of water every 15-20 minutes when working in the heat, so try and keep this up and keep your body healthy.

And when the time does come for a breather, make the most of the chance to step out of the sun for a while.

While we all do love a good tan, too much exposure can have a negative effect on your health, so be careful and make sure you can enjoy the good weather when it comes.

The Southwest London Gardener

When summer does come round, we all want to be in our garden.

This is a place where we can enjoy relaxing in the sun or spend some time with our flowers as they are in full bloom.

Working in extreme heat can be tough though, so if you need a hand, why not call The Southwest London Gardener.

Our team of gardening professionals are always ready to work in a safe and efficient manner and get your garden ready for them sunny days so that you can enjoy it to the max.

Get in touch today for a free, no-obligation quote.

We look forward to hearing from you.