Surviving a Heatwave in Your Polytunnel: My Top Tips for Keeping Plants Happy When Temperatures Soar

There are moments in gardening when you realise that one investment has completely changed the way you grow. For me, that has undoubtedly it has to be a Polyeco polytunnel.

Don't get me wrong, I love growing outdoors, but having a polytunnel has transformed not only what I can grow, but when I can grow it. It extends the season at both ends, protects crops from our increasingly unpredictable British weather and creates the perfect environment for growing everything from tomatoes and peppers to basil, cucumbers and cut flowers.

What I particularly love about the Polyeco range is that they are incredibly robust. Their galvanised steel frames and polycarbonate panels are built to withstand the kind of weather that British gardeners know only too well, whilst still creating an ideal growing environment for our plants.

Of course, when the UK decides to suddenly behave like southern Spain, even the best polytunnel requires a little extra care and attention.

So, as we navigate what feels like our annual "Operation Save the Salad" week, here are my top tips for caring for your plants in a heatwave.

Open Everything. And Then Open Some More.

Your first priority during hot weather is ventilation. Open every door, vent and window available as early in the morning as possible. If your polytunnel has automatic vents, you'll be thanking your past self for that investment right now.

The aim is to keep air moving. Stagnant, hot air is the enemy of happy plants. Good ventilation reduces stress, helps pollination and prevents temperatures reaching levels that can stop plants from producing fruit altogether.

Water Deeply, Not Little and Often

One of the biggest mistakes we make during a heatwave is panic watering. A quick splash every few hours simply encourages shallow roots.

Instead, water thoroughly either early in the morning or late in the evening, soaking the soil deeply so roots are encouraged to grow downwards. Tomatoes, cucumbers and peppers particularly appreciate a consistent watering regime and will reward you with healthier plants and better crops.

Damp Down the Floor

This is one of my favourite old gardeners' tricks. During extreme heat, water the paths or floor of your polytunnel. As the water evaporates, it helps to cool the environment and increase humidity, which many plants appreciate.

As a bonus, it also gives you a perfectly good excuse to spend five minutes standing in your polytunnel pretending you're in a Mediterranean spa.

Consider Temporary Shade

Whilst we all dream of sunshine when we're gardening in February, there absolutely can be too much of a good thing.

If temperatures are soaring, don't be afraid to create temporary shade using horticultural fleece, shade netting or, if you're anything like me, an old white bedsheet borrowed from the airing cupboard. Your plants won't judge.

Keep Harvesting Your Herbs

One of the joys of growing under cover is the abundance of herbs you can produce. Basil, coriander, dill and parsley all benefit from regular harvesting. In fact, the more you pick, the more many of them produce.

So don't save your herbs for a special occasion. Make the pesto. Brew the mint tea. Add handfuls of dill to your potatoes. Gardening should be delicious.

What Not To Do

• Don't feed stressed plants during the hottest part of the day.

• Don't prune heavily during a heatwave.

• Don't close your polytunnel overnight if temperatures remain high.

• Don't assume that because a plant looks fine at lunchtime, it won't need water by teatime.

• And perhaps most importantly, don't spend three hours inside your polytunnel at 2pm convincing yourself you're "just quickly tying in the tomatoes."

Finally, Remember to Look After Yourself Too

As gardeners, we're very good at worrying about our tomatoes, but sometimes less good at worrying about ourselves.

Wear a hat. Apply the suncream. Drink plenty of water. Take regular breaks. And if your polytunnel starts feeling more like a sauna than a growing space, it's probably time to retreat indoors for a cup of tea and admire your handiwork from a safe distance.

Because that's the real joy of having a polytunnel. Yes, it's about extending the growing season, protecting crops and increasing yields. But it's also about creating a space where you can grow more food, spend more time outdoors and enjoy the simple pleasure of nurturing something from seed to supper.

And for me, that's what gardening is all about.