Watering your garden plants in hot weather is essential for their wellbeing, especially this weekend, with temperatures forecast to rise well past 30ºC/90ºF.

Like you and I, plants need a constant water supply, or they’ll perish. Humans sweat to cool down when it gets warm, and plants do something similar – ​​transpiration.

The warmer it gets, the more plants transpire to keep cool, which requires more water uptake from their root system.

So how should we be watering our gardens during this hot spell?

Water when it’s cooler

Early morning and late evening is the best time to water your beds, as you lose less by evaporation.

Experts thought we should not water plants in full sun because water droplets on leaves caused scorching. This was, however, disproved a decade ago. But watering in full sun is not efficient, as much of the water will evaporate before soaking into the soil.

Water the soil, not the leaves

When watering, it’s vital to ensure the water soaks into the soil to the plant’s root zone, where it is needed. The depth of the root zone varies depending on the size of the plant. Small flowers and shrubs may have a 10-15cm deep root zone, whereas trees may have 1-2m or more.

Regular light watering can cause plants to develop shallower root systems, making them less drought-resistant.

Water the soil but not the plant, but don’t allow the soil surface to form a hard crust. Using a mulch of wood chips or compost can protect the soil and retain moisture for longer.

To work out whether your soil is too dry, feel it with your fingers. The earth should not look dry and pale.

Use a soaker hose

A soaker hose is a porous irrigation hose laid on the ground in a flower bed. Often connected to a timer, a soaker hose allows water droplets to gently seep through its walls to ensure water is fed directly to the plants at soil level at a slow, constant rate.

Soaker hoses allow you to precisely direct water where you need it, and they can be left to turn on and off automatically.

New plants and containers require more frequent watering

During the first season’s growth in newly planted borders, it’s vital to ensure your plants are correctly watered, as outlined above.

Freshly installed plants will require daily watering if there is no rain, at least for the first couple of weeks after planting, until they are established. Then you can ease off and drop to once a week.

After their first year in the ground, plants will be much more able to resist hot, dry weather, and you won’t need to water anywhere near this much.

Containers and hanging baskets should be watered daily or even twice daily if conditions are hot and breezy, as wind will cause the plants to transpire quicker.

If you can move containers into the shade during particularly hot spells, this will help them retain moisture.

Get to know your plants

Some herbaceous plants, such as lupins, will wilt during the day in hot temperatures, but this is their natural defence system. They will revive later when out of the full sun.

Other plants, however, will droop or drop leaves when they don’t have enough water, which is a sign of stress. You should water these plants immediately.

What about lawns?

Lawns can look dry and awful in long drought periods, and putting the sprinkler on to green them up is tempting. However, they will quickly recover once rain returns, so save water and only irrigate the plants that need it.