Plants & Gardening
The Best Time and Way to Water Plants During a Heatwave
The best time to water outdoor plants during a heatwave is early in the morning, before the day becomes hot. Water slowly at the base of each plant so the moisture reaches the roots, rather than giving the surface a quick sprinkle. If morning watering is not possible, early evening is the next-best option.
The quick answer
- Best time: early morning, ideally before strong sunshine reaches the plants.
- Second-best time: early evening, with water directed onto the compost or soil rather than the leaves.
- Best method: water slowly and thoroughly at root level.
- Check first: feel below the surface rather than watering automatically.
- Prioritise: containers, hanging baskets, newly planted plants and anything beginning to wilt.
Why early morning is the best time to water plants
Early-morning watering gives moisture time to soak into the root area before the strongest heat arrives. Less water is lost immediately through evaporation, and plants begin the hottest part of the day with access to the moisture they need.
It is also easier to spot which plants genuinely need attention before leaves naturally droop in the afternoon heat. Some plants wilt temporarily on a very hot afternoon even when their soil is still moist, so checking the compost or soil is more reliable than reacting to leaves alone.
Can you water plants in the evening?
Yes. Early evening is a sensible alternative if you cannot water in the morning. The temperature is lower, so water has more opportunity to soak into the soil instead of disappearing rapidly from the surface.
Aim the water at the base of the plant and avoid leaving foliage unnecessarily wet overnight. Damp leaves can create favourable conditions for some fungal problems, while water caught on foliage is water that has not reached the roots.
A thirsty plant should not be made to wait
If a plant is clearly distressed and its soil is dry, water it when you notice. Midday is not the most efficient time, but giving a genuinely thirsty plant water is better than leaving it struggling until evening. Apply water slowly at soil level and, if possible, provide temporary shade.
How to tell whether a plant needs water
Do not judge only by a dry-looking surface. Push a finger a few centimetres into the compost in a pot, or use a trowel to check below the surface in a border. Water if it is dry at root level; wait and check again later if it still feels cool and moist.
During a heatwave, inspect pots and hanging baskets at least daily because their limited volume of compost can dry much faster than garden soil. Small pots, dark containers, baskets exposed to wind and plants against a sun-warmed wall may need particularly close attention. Light summer rain may wet only the surface, so check underneath before assuming it has done the job.
The best way to water plants in hot weather
1. Water the roots, not the leaves
Place the spout of a watering can close to the compost or soil and direct the water around the root area. Overhead sprinkling can lose water to evaporation, leave foliage wet and fail to deliver enough moisture where it is needed.
2. Water slowly and deeply
A quick splash may darken the surface without reaching the deeper roots. Apply water gradually, pause to let it soak in and repeat if necessary. In borders, a thorough drink given when needed is generally more useful than frequent light sprinkling, as it encourages roots to grow farther into the soil.
3. Rehydrate very dry pots in stages
Potting compost that has become extremely dry can shrink away from the sides of its container. Water may then run straight through the gap without soaking the root ball. Add a little water, allow it to absorb, then return for another slow watering. Check that excess water can escape through clear drainage holes.
4. Use a watering can for control
A watering can lets you direct water accurately and judge how much each plant receives. If you use a hose, choose a gentle setting and keep the flow close to the soil. Avoid a powerful jet that washes compost away or runs off before soaking in.
Which plants need water first during a heatwave?
- Hanging baskets and small pots: these have little compost and can dry rapidly.
- Newly planted flowers, shrubs and trees: their roots have not yet spread into the surrounding soil.
- Flowering patio containers: lots of growth and flowers can mean high water demand.
- Plants in windy or full-sun positions: moving air and direct heat increase moisture loss.
- Plants showing genuine stress: check the soil first, then water if it is dry.
Established trees and shrubs growing in the ground usually cope better than containers, although recently planted or visibly stressed specimens may still need a deep watering. Lawns can often be allowed to brown temporarily and recover when wetter weather returns.
Help pots and planters stay moist for longer
- Move portable pots away from intense afternoon sun where suitable for the plant.
- Group containers together in a sheltered position to reduce exposure.
- Remove weeds that compete with your plants for moisture.
- Use collected rainwater when available and follow any local water-use restrictions.
- After thoroughly watering, cover exposed compost with a suitable mulch to slow moisture loss.
Our guide to using bark around planters in hot weather explains how to add a moisture-saving surface layer without piling it against stems. For broader seasonal advice, see how to keep outdoor plants healthy in hot weather.
Common heatwave watering mistakes
- Giving every plant the same amount of water without checking its soil.
- Sprinkling the surface briefly instead of soaking the root area.
- Directing most of the water over leaves and flowers.
- Assuming a short rain shower has watered containers thoroughly.
- Leaving pots in decorative covers or saucers full of water when the plant does not tolerate waterlogged roots.
- Continuing to water already-wet compost because the leaves look tired at midday.
Frequently asked questions
What is the best time to water plants in a heatwave?
Early morning is best because temperatures are cooler, evaporation is lower and plants have moisture available before the hottest part of the day. Early evening is the next-best choice.
Is it bad to water plants in full sun?
It is less efficient because water evaporates more quickly, but do not leave a genuinely dry, distressed plant without water. Apply it directly and slowly to the soil, then move the container into suitable shade if possible.
Should plants be watered every day in hot weather?
Not automatically. Containers and hanging baskets may need daily or even more frequent checks, but the correct schedule depends on the plant, pot, soil, wind and position. Test the moisture below the surface and water according to need.
Is morning or evening watering better?
Morning is usually better. It prepares plants for the heat of the day and avoids foliage remaining wet overnight. Evening remains a useful alternative when morning watering is impractical.
Should I water leaves during a heatwave?
Concentrate on the soil or compost around the roots. Wetting the foliage wastes some water and may encourage disease, especially if leaves stay damp overnight.
Give plants the water they need, where they need it
The simplest heatwave routine is to check plants early, water only those that need it and deliver a slow, thorough drink at root level. Pay particular attention to pots, baskets and recent planting, then use shade, grouping and mulch to help that moisture last longer.
You can find more practical plant and flower advice from The Flower Fountain in Stoke-on-Trent through our florist FAQ hub. For advice about plants currently available from our shop, please contact us.
Further reading: RHS advice on watering plants wisely.
