How to water your garden in a heatwave: tips for saving water while keeping plants alive

·4-min read
Water butts don’t have to be ugly as this galvanised option from  Garden Trading (£250) shows  (H&P)
Water butts don’t have to be ugly as this galvanised option from Garden Trading (£250) shows (H&P)

From tomato plants to lawns, much of what we grow in the city isn’t cut out for a summer heatwave. London’s parks are parched, green grass is now golden, and our gardens aren’t far behind.

But before you reach for the hose, ask yourself what will happen if you don’t water your garden. Established trees that have been in situ for a couple of years or more can normally fend for themselves when it comes to finding water thanks to well developed root systems. Just think how often you see the millions of mature trees that line our streets and parks being watered — the answer is never.

However, all plants in containers will need your intensive care as the mercury rises, and plants endemic to wetter regions will need a helping hand too.

How to water in a heatwave

Nearly all plants absorb the majority of water through their root system so, if you do need to water, that is where it should be going. Close to the base of the plant and on the soil or compost around the plant.

Watering the leaves as the sun beats down can cause them to burn, as the light is magnified by water droplets.

How much water you give a plant is also important. When the ground is dry, it is difficult for water to get down to the roots, instead it lies on the surface. It’s better to water thoroughly and less often than splashing a little water around every day.

A mature tomato plant needs at least two litres of water a day. Larger plants and plants in containers are always going to be more thirsty.

You can create saucers or shallow craters around plants in the ground using excess soil, and in containers (as long as there are holes in the bottom of the pot) you can fill the pot to the brim, allowing it to soak in before repeating.

Let go of the lawn

Grass is tough stuff. If you do have a lawn that’s looking parched, it will recover the moment we get a downpour so resist the urge to water it.

If you want a space outside to sit and enjoy the sun, think about using gravel, woodchip or a permeable surface.

When to water

When you water is just as important as how you water. The best time is in the evening.

Once the sun has set, less water evaporates before it has a chance to penetrate the soil, and night allows time for the water to soak in, and for the plant to recharge before facing another day in the sun.

Second best is early morning, but you should avoid watering in the middle of the day as much of your hard work will be quickly lost to evaporation. If your garden is a bit of a slug and snail festival, watering in the morning might work better as the damp and dark are ideal dining conditions for these garden gastropods.

Three ways to minimise water use in the garden

There are a number of ways to conserve water and minimise your usage around the garden.

Mulch around plants

Organic matter is often overlooked in the garden, but providing a thick layer of compost made at home or from the shops, well rotted manure wood or bark chippings, does amazing things for water retention.

Admittedly this is best done in late autumn or early winter, when summer has long been forgotten, but even adding it now will help lock in moisture.

Over time, adding organic matter can increase the water holding ability of soil by up to 60 per cent. Incredible stuff.

Ditch the hose

Hosepipes are notorious for wasting water. Most leak. Left on for just an hour, they use more water than the average person uses in a whole week — and it’s easy to be careless.

Using a watering can will force you to be more targeted with your watering and give you a good idea of how much water you are using.

Toast has a racing green watering can for £20, or Labour and Wait has a fiery orange one for £28.

Collecting water

If you’ve got the space to collect water from your roof and you aren’t doing it, more fool you.

Capitalising on the rain when we do get it, and storing it, is like hacking the system. Why pay for something when you can get it for free?

If you’re put off by the green plastic blob lurking in the corner of your garden, for a little more you can now buy some very sleek water butts, including this galvanised option from Garden Trading (£250) or a converted wine or whiskey barrel from Celtic Timber (£195).

You can also reuse water from cooking and cleaning.