How often should you water your garden in the hot weather? The ultimate heatwave watering guide

Trying to figure out how much water your garden needs in this obscenely hot weather? We're here to help

A metal watering can sat alongside a pot of flowers at RHS Chelsea Flower Show
(Image credit: Heather Young/Future Publishing Ltd)

How often should I water my plants in hot weather? Like, really?

It's a question that every amateur gardener will, at some point during a heatwave, ask the world at large. And then Google. And then everyone they know, to be honest. After all, there's no point spending hours on all of our favourite garden ideas if we're going to let them get wiped out by a scorching UK summer.

How often should I water my garden in hot weather?

While we are all guilty of making one or two (or more!) gardening mistakes during hot weather, figuring out how often to water our plants during a heatwave doesn't need to be one of them.

A terracotta planter with orange flowers inside it, photographed at RHS Chelsea Flower Show

(Image credit: Heather Young/Future Publishing Ltd)

With that in mind, then, we have worked together with some top gardening experts to produce the ultimate heatwave watering guide. Because, as ever, how often you water plants in hot weather depends on a variety of factors.

No need to thank us, honestly. Churning out deliciously easy garden ideas is all in a day's work...

1. Established plants

Succulents in mulched concrete at RHS Chelsea Flower Show

(Image credit: Heather Young/Future Publishing Ltd)

'Established plants will require deeper watering in a heatwave,' says Christopher O'Donoghue, the co-director of Gardens Revived. 

The aim of a deep watering is simple enough: you want to allow your water to soak thoroughly into the roots. This will need to be done less frequently to prevent any overwatering issues, so once or twice a week should still be sufficient during hot weather.

2. New plants (not in pots or containers)

'New trees and shrubs planted into your garden are best watered only once a week while they get established,' says Morris Hankinson, founder and managing director at Hopes Grove Nurseries

'Twice, if it’s really scorching.'

A lush green garden, made up of hedged borders, paving and moss at RHS Chelsea Flower Show

(Image credit: Heather Young/Future Publishing Ltd)

Morris adds: 'Little and often daily watering will only encourage the developing roots to stay close to the surface making the plant vulnerable to failure when you stop watering. 

'A thorough wetting followed by a distinct drying cycle, on the other hand, will encourage the new roots to search deep into the soil, making the plant healthy and resilient.'

3. Plants in containers and hanging baskets

'Due to the limited soil volume and exposure to heat, potted plants tend to dry out quickly,' says Christopher. 

'These will most likely require watering once or even twice a day.' 

However, if you struggle to keep up with this you can try the Gardena Aqua bloom set which our Deputy Digital Editor Rebecca Knight uses to keep up with watering her windowsill pots. 

'It took a little bit to set up, but it's been great at keeping my plants watered during the heatwave. The best part is that because it is solar powered and draws its water up from a bucket or similar I could easily disguise the watering system on my windowsill, and not worry about not having an outdoor water source.'

Potted pink peonies at the RHS Chelsea Flower Show

(Image credit: Heather Young/Future Publishing Ltd)

Morris adds: 'Some plants, such as Hosta and Fuchsia, love a misting over their leaves.

'It is fine if you do this, but make sure you spritz them after the heat of the day has passed. Later in the evening is best.'

How to determine if a plant needs more water than usual

All of us feel drier than ever during a heatwave, and the same can often be true of our plants. That being said, not all varieties of plants will need the same amount of water: some will be very thirsty and others far less so. 

'When you are watering, check the compost or soil first to see if it’s still wet from the last watering and give any specimens that are still wet a miss,' advises Morris. 

'A surprising number of plants are killed by overwatering: it is one of the easiest garden watering mistakes you can make.'

A living wall / vertical garden installation at RHS Chelsea Flower Show

(Image credit: Heather Young/Future Publishing Ltd)

Christopher adds: 'The key thing is to keep an eye out for signs that the plant needs water, so check the soil with a finger for shallow root systems or use a moisture metre if extra depth is needed. 

'Keep an eye on the plant, too: are the leaves curling and starting to dry? Is the plant starting to flop over and is no longer turgid? These are all signs that it needs more water!'

However, if you are still nervous about getting it wrong you can set up a smart irrigation system with a moisture sensor to help you monitor it. We are big fans of the Gardena moisture sensor which can be paired with a smart control so the automatic watering will not happen if there is already sufficient soil moisture.

When should I water my garden in hot weather?

Aim to water your plants very early in the morning or in the evening, during the cooler parts of the day.

As Morris advises: 'Watering during the heat of the day won't just cause the water to evaporate too quickly for your plants to absorb it, but it also heightens the risk of scorching the leaves of more delicate specimens. 

'If you must water during the day, then only wet compost, or soil surface.'

How often should you water in very hot weather?

There is no one size fits all approach to watering, even during a heatwave.

'Treat each plant as an individual,' advises Christopher, 'and do your research. Remember, while a potted plant may need watering once or even twice a day during hot weather, a mature tree or shrub might only need a drink in extreme drought. 

'Established garden plants, too, are far more appreciative of a deep and thorough drink than they are being watered little and often.'

How do you keep soil moist in the summer?

If your aim is to keep soil moist during the summer, Morris advises that you start using a good-quality mulch, which you can pick up on Amazon

'A mulch is a layer of organic matter on the surface of the soil or compost that will stop weeds from growing and massively reduce water evaporation, so you don’t need to water as much, and what you do add goes much further. It also keeps the roots cool in hot weather. 

'Trees and shrubs in the ground can be mulched with bark chippings, cocoa shell, home made garden compost or even lawn mowing’s. For your pots and containers, it’s better to use something fine like cocoa shells or coir. It even works for hanging baskets!

Kayleigh Dray
Acting Content Editor

Kayleigh Dray became Ideal Home’s Acting Content Editor in the spring of 2023, and is very excited to get to work. She joins the team after a decade-long career working as a journalist and editor across a number of leading lifestyle brands, both in-house and as a freelancer.