When to water plants – to keep them healthy and use water wisely

The question of when to water plants is a crucial one – whether it’s garden plants, veggies, or the lawn.

While even the least green-thumbed of gardeners knows that plants need water, what can be less appreciated is that the timing of watering is vital in keeping the plants you’ve chosen as flower bed ideas as well as edibles healthy, and to avoid wasting water.

Our guide has the details you need on when to water plants, and why, to optimize their growth and conserve a precious resource.

When to water plants

The best answer as to when to water plants is to get up early to perform the task. ‘To keep your plants at their healthiest, the best time of day to water your garden is in the morning,’ says Samantha Richards of garden gazebo experts Gazeboshop. 

Why the morning? ‘A morning water means plants have a reserve of water to use throughout the day so that they don’t end up parched,’ says Josh Papworth from the oldest manufacturer of watering cans in the world, Haws. ‘The cooler temperature in the morning also means that the water has a chance to get down to the roots, rather than evaporating in the heat of the sun.’

Not feasible to water garden plants and veggies in the morning because of other commitments? If that’s the case, water in the evening instead. 

This is the lowdown on when to water plants.

When to water plants in the yard

The morning is best for watering garden plants from flowers, shrubs and climbers to vegetable gardens.

‘This is because you’re giving the soil the best chance of hydration since the coolness of the morning allows the water to run down to the root system before evaporating,’ says Tom Hilton, director of hydroponic specialists, National Greenhouse. 

‘A morning watering will also set the plants up for the day with a good bank of moisture beneath the soil to help them thrive during a warm day.’

The demands of work and family can mean it’s impossible to water the backyard in the morning, though, so if time isn’t available, water in the evening. The cooler conditions of the evening ensure less water evaporates. The downside of nighttime watering? Damp leaves and soil can provide the conditions for mildew. 

‘The wet conditions can also encourage slugs and snails to be active, hence late afternoon and early evening waterings should have some time to dry before the nocturnal pests arrive,’ advises Benjamin Pope, author of What to Grow, Sow and Do, published by Frances Lincoln.

Pay attention to the thermometer, however. ‘It’s worth remembering, if temperatures are due to lower significantly to freezing, then this should be avoided and watering early in the day is better,’ says Benjamin.

Why should you avoid watering during the day? ‘Watering during the sun’s peak or when it’s a lot warmer in the day can speed up the process of evaporation and drying out the soil, so doing it during a cooler period is best,’ says Tom. 

But if you were thinking that watering during the day is a no-no because the droplets scorch the leaves, this is a myth. Even so, daytime watering still isn’t a good idea for the reasons above.

When to water outdoor container plants

Fan of container gardening ideas? Be aware that plants in pots and plants for hanging baskets can need watering twice daily when temperatures climb to 85ºF (29ºC) and over, so water in the morning and the evening.

When to water indoor plants

The rule of thumb for indoor plants is the same as for those in the backyard. ‘The best time of day to water them is in the early morning hours, especially in the hot summer months,’ says horticulturist Charlotte Bailey of Oh So Garden. ‘This not only prevents excessive evaporation but also allows the leaves and stems plenty of time to dry out, reducing the risk of infections such as fungal leaf spot.’

Is nighttime an option for houseplants? ‘Watering at night is OK in warmer months, however in cooler months it could lead to water sitting stagnantly on your plant’s soil,’ says Toby Schulz, CEO of Lawn.com.au, which provides advice for indoor and outdoor plants.

When should I water my plants every day?

The best time to water plants is in the morning, although you can opt for watering in the evening as an alternative if circumstances don’t permit watering first thing. 

But be aware that plants’ needs vary and watering every day might only be required for container plants and hanging baskets when it’s very hot and sunny. Otherwise, you can let plants dry out somewhat before watering again. 

Watering technique is important, too. ‘When watering it is best to give a thorough soak as opposed to a quick douse that will just wet the surface and mostly evaporate,’ says Benjamin Pope. ‘Watering each plant for 30 seconds or so before moving on to others and then revisiting for a second or third time will ensure that the water permeates deep into the soil or compost, resulting in your having to water less frequently.’

Note that watering indoor plants is a different matter, so seeking separate advice on that is wise.

Is it OK to water plants at night in summer?

It is OK to water plants at night in summer – although the morning is better. ‘It's not the end of the world to water in the evening as it’s one of the cooler times of the day and can allow the roots and soil to soak up the water for good hydration,’ says Tom Hilton. ‘Just be mindful of overnight damp and how you can then protect plants from mildew.’