How to... water your plants

No one wants to waste natural resources, least of all gardeners. Adam Pasco explains how much water your plants need to flourish

Even if you don’t have a hosepipe ban in your area, avoid using sprinklers, which can use more than 1000 litres of water an hour. This is just a waste. Here are some tips on how to water your plants efficiently.

Watering techniques

Water individual plants thoroughly, close to their main stem, to help water drain down to their roots. Avoid watering the whole bed with a rose fitted to your watering can – it usually just wets the soil surface and the water evaporates off without ever reaching the roots. It also wastes water by wetting soil between plants where nothing is growing.
Help plants to survive without the need for regular watering, by encouraging them to be deep rooting. After planting, water them in thoroughly then avoid further watering until needed. Water only when the soil is dry and the plants are ready for more, and when you do, water thoroughly.
Plants that are continually watered do not develop deep root systems, as roots stay in the moist surface layer. Shallow-rooted plants are more prone to damage during drought, while deep-rooted plants explore widely and deeply for soil moisture, making them better able to survive short periods of drought.
Sink a deep flowerpot or pipe down into the soil alongside plants. Water directly into this pot so that water soaks directly down into the root zone. This avoids wetting the surface layers of soil, which wastes water by evaporation.
Run a seep hose along rows of strawberries or other plants requiring regular watering, and cover this with a mulch of straw or compost. Attach the trickle hose to a water butt filled by rainwater or with grey water from the house. These aren’t included in the hosepipe ban, but it’s always best to check with your water company, as some areas do have different restrictions.

Don't go to pot

Plants in pots demand regular watering, but this should still be made efficient. Here’s how.

Line your terracotta pots with polythene, such as old pieces of compost bags. This will help reduce water lost through evaporation.
Place saucers under your patio pots to collect water, reducing waste from run-off.
Always mix water-retaining gel into compost used for pots and baskets at planting time. If you forgot to do this, make deep channels into the compost with a cane and pour dry gel granules into these.
Install a timer-controlled drip irrigation system to water pots and baskets. This will accurately deliver water precisely where and when it’s wanted. Despite their efficiency the use of these systems is still prohibited under a hosepipe ban.
Group pots together to help create a moist atmosphere around them, and to make them more efficient and easier to water.
Choose drought-tolerant plants, where possible, in place of plants with high water demand. For instance, pelargoniums and petunias require less watering than begonias and fuchsias, and silver-leaved plants are generally more drought tolerant.
Some pots and baskets have a built-in reservoir in their base, collecting water to prevent it simply dripping through and being wasted.

Good gardening sense

There are a number of practical measures that can be taken to help plants survive in areas of low rainfall or where drought is forecast. All make perfect sense to reduce water usage, regardless of whether a hosepipe ban is in place or not.

Mulch all your flowerbeds, covering soil around plants with a deep layer of compost. Make as much of your own compost as possible, or buy bags of peat-free potting compost, bark or any other suitable material. Spread generously to form a minimum layer of 5-7cm (2-3in) deep, to help conserve soil moisture and reduce the growth of annual weeds.
Mulch round vegetables, fruit trees, and along rows of raspberries, strawberries and other soft fruits.
Cover borders with a permeable membrane before planting, and plant through this. The membrane will suppress weeds, reduce evaporation and help retain soil moisture. Spread gravel or an ornamental mulch over the membrane.
Bury generous wads of soaked newspaper under runner beans, marrows, pumpkins and other crops that require plenty of water at planting time. These will hold onto moisture for roots to explore.
Weeds use water to grow, so weed regularly to reduce competition with other plants.
Use screens or windbreaks to reduce the effects of drying winds.
Collect rainwater to top up ponds and water features.
Plant small, rather than big. Small young plants usually establish and root more deeply than larger, more expensive ones.
Soil fungus called mycorrhizae play a part in helping plants survive drought. Our understanding of these microscopic organisms, which develop symbiotic relationships with plants, is developing slowly, and mycorrhizae are now available for gardeners to buy and add to their soil.

This feature originally appeared in Gardeners' World magazine.

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