Saving water in the Garden

How do we deal with watering as gardeners in order to ensure that our plants get the water that they need without using up too much of this scare resource? Future projections have suggested that during summer the number of dry days will increase, with heavier rain in between. This may mean changing how water is collected and stored to prevent adverse effects on households and agriculture.

August has traditionally been thought of as a month when there is plenty of rain in the UK. However, recently, summers have been getting drier. According to the Met Office, “As global temperatures rise, there is a risk drought will become more frequent in the UK.  Winters across the UK are projected to get wetter, while summers are expected to become drier. However, it is the distribution of this rainfall that will determine future UK drought risk.

Store water

The first thing that we can do is to store as much rainwater as possible. By installing a water butt and connecting it to your gutters, you can collect rainwater and use it on the garden. According to the RHS website: “Even in dry districts, 24,000 litres (5280 gallons or 150 water butts) could be collected from the roof each year”. Rainwater is, in any case, better for most plants than tap water because it is free from chemicals such as chlorine which damage them. However, do not use water from a water butt on newly sown seedlings, as these are susceptible to infections caused by fungal spores which may have built up in the water butt.
During heavy rain it’s worth leaving out as many buckets or bowls as you can to collect rainwater and to pour this into watering cans when you need it. Greywater (from baths and washing up bowls) can also be used on plants. The RHS recommends storing it for no longer than 24 hours in order to minimalise bacterial growth and recommends that “there should be no problem with small-scale, short-term use of grey water to tide plants over in summer drought. An exception is on edible crops, due to the risk of contamination from pathogens in the water”.

Treat your soil

A soil that is rich in organic matter such as compost or garden waste has a better structure and will retain moisture more easily. For this reason, it’s worth having a compost bin and digging the contents into the soil once they are well-rotted. Compost encourages the production of beneficial bacteria and fungi that break down organic matter to create humus, a rich nutrient-filled material. Compost can also be used as a mulch which is applied when the ground is moist in order to conserve moisture. Other types of mulch include bark chippings, straw, and grass.

What to water

Plants have different needs for water, so, when this is scarce, it’s often necessary to prioritise those that need a lot of water or need watering more frequently.
These include:

  • newly sown or newly planted areas, particularly those containing annual flowers or vegetables sown in the Spring, since they have shallower root systems than those sown or planted in the Autumn. Leafy vegetables, such as lettuce and spinach, require a lot of water, whereas crops like onions can be left without watering.
  • plants growing in pots. Place drip trays below the pots to collect drainage and use a water retaining gel or use self-watering pots or baskets.
  • trees and shrubs planted less than five years ago. These may suffer drought-stress without water. Established trees and shrubs can generally be left.

Watering established lawns is generally not recommended, and they usually recover after a period of drought. A hose and sprinkler can use about 1000 litres an hour, equivalent to the same amount of water one person would normally use in a whole week, so it’s not surprising that hose pipe bans are sometimes enforced in times of drought.

lettuce

When and how to water

If you use a watering can rather than a hosepipe, you can direct water at the roots of a plant, where it’s needed. Cut off plastic drinks bottles can be inserted into the ground so that water can be poured directly into these. It’s best to water late in the evening or early in the morning to avoid as much evaporation as possible. It’s also best to keep leaves dry to avoid diseases, and leaves that are watered in the sun can develop burn marks. Apply water gradually to avoid run off and to allow the water to fully penetrate the soil.
It isn’t always easy to judge when and how to water. According to the RHS, these are some of the signs that your plants need more water:

  • Less than expected growth of foliage, or production of fruit or flowers
  • Leaves or stems that look dull or lost their shine, sometimes darker or paler than normal
  • Change in position of leaves, they may angle downwards or start to curl
  • Wilting (take care though as this can also indicate overwatering!)
  • Pots become lighter in weight
  • Pots blowing over in the wind
  • Symptoms of powdery mildew.

The RHS also recommends watering more thoroughly, but less frequently. It also warns against over-watering, because plant roots need air as well as water to grow well.

Drought tolerant plants

With the challenges that climate change presents and the likelihood of hotter, drier summers continuing, it’s perhaps a good time to think about growing plants that don’t need quite as much water.  In doing so, it’s worth looking at plants that thrive in countries that have dry climates, such as those in the Mediterranean.  These include:

  • Lavender
  • Salvias
  • Rosemary
  • Thyme
  • Oregano
  • Phlomis
  • Santolina
  • Tarragon
  • Cistus
  • Artemisias
lavendel

A field of lavendel

SAntolina Chamaecyparissus
Santolina Chamaecyparissus (Cotton Lavender

Plant Mediterranean plants in the Spring when the soil is warming up. Many of these plants will suffer from root-rot if planted in autumn and become cold and damp over winter. After planting, mulch with gravel or straw to help retain moisture while the plant establishes.

thymus serpyllum

Thymus Serpyllum (wild thyme)

Many drought-tolerant plants have silver or grey-green leaves, and some have a coating of fine hairs on their leaves or stems that traps moisture around plant tissues and prevent plants from drying out.  These include

  • Eryngium (sea holly)
  • Lychnis coronaria (rose campion)
  • Stachys byzantine “Silver carpet” (lambs’ ears)
  • Caryopeteris clandonensis “Sterling Silver”

Other plants, such as aeoniums and sedums, have fleshy leaves which act as water storage systems.

In the vegetable garden, root crops, such as beetroot, carrots and parsnips are fairly drought tolerant, whereas salads and other leafy vegetables are more vulnerable to drought conditions.  And tomatoes, once they start to produce fruit, need less water as this tends to encourage a lot of leaf growth at the expense of the fruit.

backyard

Especially if you have sandy or gravelly soil, you could consider having a gravel garden.   These tend to be lower maintenance and have the advantage of covering dry, exposed areas of soil and offering good drainage.

Where to find inspiration

In the UK there are various places to visit where you can see water saving ideas put into practice. These include

  • Ryton Organic Gardens, near Coventry, Warwickshire
  • Centre for Alternative Technology, near Machynlleth, Powys
  • Royal Botanic Gardens, Kew

If it’s not possible to visit in person, all of these organisations have websites which provide useful information on water conservation.

alernative technology

Centre for Alternative Technology

There are a number of places to visit which have dry gardens or focus on growing drought-resistant plants.

These include

  • The Beth Chatto Gardens, near Colchester, Essex
  • Cambridge Botanic Gardens, Cambridge
  • RHS Garden Hyde Hall, near Chelmsford, Essex
  • The Savill Garden. Windsor Great Park, Windsor, Berkshire

A useful list of plants for a dry garden can be downloaded from the Cambridge Botanic Gardens website.  Beth Chatto, whose mantra was “the right plant for the right place” wrote the definitive book “The Dry Garden”, based on her experience of creating a garden in one of the driest parts of the country.

 So, although it takes some thought and planning, adapting your garden so that it can cope with drought conditions is not impossible.

 “Making our gardens more resistant to drought is not necessarily about digging them up and starting again, but thinking about appropriate soil cultivation, plant choice and garden maintenance” (RHS website)

pathdrygarden

The Dry Garden, Savill Gardens, Windsor Great Park

Caroline Bowman

ABOUT THE AUTHOR

Caroline Bowman has been hooked on gardening ever since she grew some thyme from seed and planted it in a window box when she lived in a flat in London. Fifty years later she is still hooked on gardening, but now she lives in Lincolnshire in England where they have quite a big suburban garden as well as an allotment, where they grow fruit and vegetables. Caroline loves flowering plants, in particular, herbaceous perennials and she likes finding out about the more unusual varieties that will do well in the English climate and soil.

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