Energy, Waste, Water and Recycling  In the UK it is possible to have a beautiful and productive garden without using any mains water. How much water can we save? Average UK outdoor water use, which includes garden watering and car washing, accounts for only about six per cent of annual domestic water consumption. However, on hot summer evenings 50 per cent or more of the water supply may be used for garden watering when supplies are most stressed. Water-efficient gardening A healthy soil with plenty of organic matter will retain moisture and nutrients. Choose plants for drought tolerance and compatibility with your soil and intended position. Planting new shrubs and trees through plastic will retain moisture and control weeds, while loose mulches can be used to similar effect around established plants. Low-maintenance alternatives to planted areas include gravel, coloured glass nuggets and decking. Lawns are the thirstiest part of a garden. Letting the grass grow longer helps shade the soil and reduces the need for water. If you must water your lawn, remember that infrequent soaking is far more beneficial than regular sprinkling as it encourages the roots to search for water stored deep below the soil's surface. If the grass turns brown, it does not mean that it has died: it will eventually recover when it rains. Some varieties of grass are particularly suited to dry conditions, such as fescue grasses and smooth stalked meadow grass. Plants for a Mediterranean-style garden The following plants thrive in hot and dry conditions and are best suited for poor, free-draining soils: African lily Lavender Buddleia (butterfly bush) Peruvian lily Californian lilac Pink Californian poppy Red-hot poker Catmint Rock rose Daisy bush Rosemary Evening primrose Straw daisy Foxtail lily Thyme French honeysuckle Tulip Rain and greywater Rainwater can be collected in butts and used in watering cans (see also series No. 4). All gardens will benefit from water butts, which you can disguise with suitable plants such as clematis (many varieties of which are drought tolerant). A range of manufactured or reclaimed containers is available locally or by mail order, and water companies often sell water butts at subsidised prices. Garden centres sell suitable pumps to allow the use of hoses with trigger sprays, which are ideal for larger gardens. Greywater from baths and showers can be used safely on most non-edible plants, provided it is applied to the soil rather than foliage and is not hot. Valves are available to divert wastewater from upstairs bathrooms to a hose when needed. A number of books and websites provide detailed advice on greywater gardening. Watering – equipment and techniques Having minimised your garden’s need for water and maximised your collection of rainwater, it is important not to waste the water you do use. Generally, the following principles apply: don’t use watering-can roses (except for seedlings), as the water does not go directly to the roots where it is needed; don’t over-water plants: this can cause as much stress as under-watering; frequent light watering is not good as it encourages shallow roots rather than deep moisture-seeking ones; do water in the early morning or in the evening to avoid evaporation. If you are not affected by a hose pipe ban - check your garden hose for leaks and fit it with a trigger to control the flow. An aerating nozzle allows you to water roots without washing away the soil or having to use the less efficient spray pattern. Many water companies require households using sprinklers to have a water meter fitted. Drip irrigation has the potential to save water, particularly when used in large planting schemes. However, it may pose problems, and has limited application for small gardens. Incorrectly installed systems can waste water and care must be taken not to contaminate mains water supplies through backflow. Porous hoses (so-called "seephoses") are typically left attached to taps and irrigate by "weeping" water on to or below the ground surface. They appear attractive as alternatives to hosepipes, but can become irreversibly expanded if overpressurised in use, which will result in them wasting very large amounts of water.