Why Little and Often Does More Harm Than Good

It is tempting, when the forecast shows another week of sunshine and the thermometer creeps past 25°C, to reach for the watering can every evening and give everything a quick sprinkle. Please resist. A daily splash wets only the top centimetre or two of soil, and that is precisely where you do not want your plants' roots to be. Roots grow towards moisture, so shallow watering quietly trains everything in your garden to depend on you.

The better approach is to water deeply and less often. A thorough soak that pushes moisture 15–20cm (6–8in) into the soil encourages roots to travel downwards, where the ground stays cool and damp for far longer. Plants grown this way cope better with a heatwave, need less intervention, and are noticeably more resilient by late August. Aim for one good soaking every three to five days in open ground, rather than a token gesture every night.

Early Morning Is the Golden Hour

If you can only choose one time to water, choose early morning — ideally before 7am, while the air is still cool and the sun is low. Water applied then has a chance to sink in properly, and far less is lost to evaporation. It also means foliage has time to dry through the day, which helps keep problems such as powdery mildew and botrytis at bay, and gives slugs and snails less of a damp invitation overnight.

Evening is the second-best option, useful if mornings are impossible, but leaves stay wet for hours and that suits slugs and fungal disease rather well. Midday watering is largely wasted on thirsty soil, though for containers collapsing visibly in the heat, a rescue drink is better than nothing at all.

How to Tell When a Plant Really Needs Water

Before you reach for the can, check. Wilting at midday is not always a cry for water; many plants droop to reduce moisture loss and perk up again by evening. Look beneath the surface instead.

• The finger test: push a finger about 5cm into the soil. If it feels dry at that depth, water. If it is cool and damp, wait another day.
• Lift the pot: a dry container is surprisingly light. Get used to the weight of a freshly watered pot and you will seldom need to guess again.
• Check under mulch: bark or compost can look bone-dry on top while the soil below is still moist.
• Watch for clues: dull, greyish foliage, curled leaves and flowers dropping early all suggest genuine thirst. Yellowing leaves and soggy compost usually mean you have been too generous.

Getting Water to the Roots, Not the Path

Water slowly, at the base of the plant, and give the soil time to absorb it. A fast blast from a hose mostly runs off and away, especially on baked ground. Use a rose on the watering can, or a soaker hose on a gentle trickle, and water in two or three passes rather than one deluge.

• Build a basin: draw up a shallow ring of soil around thirsty plants so water pools and sinks rather than running off.
• Water in stages: give half, pause while it soaks in, then give the rest.
• Go below the surface: sink a plastic bottle with a few holes punched in it beside tomatoes, courgettes or runner beans and fill it — water reaches the roots directly.
• Mulch generously: a 5–7cm layer of compost, bark chippings or grass clippings can cut evaporation from the soil surface dramatically.

As a rule of thumb, a large shrub or climbing rose appreciates around 10 litres in one go, a tomato or courgette plant about 5 litres, and a 30cm pot will want topping up whenever its weight tells you it has dried out.

What to Water First When Supplies Are Tight

Hosepipe bans and dried-up butts are a familiar part of a British summer. If water is limited, spend it where it counts.

• New plantings: anything put in this year, plus trees and shrubs within their first two years, has shallow roots and no reserves. They come first.
• Containers and hanging baskets: they cannot reach deeper soil and can dry out in a single hot day.
• Vegetables in flower or fruit: courgettes, beans, tomatoes and soft fruit will drop their crop if stressed now.
• Prized perennials and young hedges: worth a soak, especially on sandy soil.
• The lawn: last, always. A brown lawn is dormant, not dead, and will green up within a fortnight of steady rain.

Small Habits That Make a Big Difference

Little adjustments around the garden add up through a dry spell. Water your pots over a bucket and reuse what drains through. Keep a can in the kitchen for cooled washing-up water on established ornamental beds, though avoid it on edibles you will eat raw. Leave the lawn a touch longer than usual, and resist the urge to hoe or fork dry ground, which only exposes more moisture to the air.

Finally, do not feed a thirsty plant. Fertiliser on dry roots can scorch them badly. Water first, let the plant recover for a day or two, then feed if it needs it. Water wisely, and your garden will repay you with stronger roots, healthier plants and far less time spent standing at the tap.