The UK is in the throes of an abnormally hot summer, with a heatwave sweeping across southern parts of the country.
The Met Office has issued several weather warnings over the past few weeks and water companies have had to impose hosepipe bans in some counties.
This poses problems for gardeners – but the good news is that you can reuse certain types of water from your home in your garden.
Can I use washing-up water on my garden?
Recycled or “grey” water should be used with care, but can be useful in times of water shortages.
Plants can be watered with shower, bath, kitchen and washing machine water (from rinse cycles) – collectively referred to as “grey” water.
This type of water varies in quality and may contain contaminants such as soap and detergent.
Fortunately, soil and potting composts are effective at filtering these contaminants out, and the residues can even sometimes act as a mild fertiliser.
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To minimise bacterial growth, grey water should be saved for only 24 hours, unless filtered through a reed bed or professionally designed system.
It is best applied by watering can: grease and fibres can clog irrigation systems.
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.
In recent experiments on a few popular border perennial plants and sub-shrubs, we at the Royal Horticultural Society (RHS) found that applying grey water for several weeks over the summer did not significantly affect plant function.
However after six weeks some plants (eg Stachys byzantina) benefited from a rinse-through with tap water as they were beginning to show signs of salt stress.
Long-term, extensive use, or permanent altering of indoor plumbing, should not be attempted without expert advice.
Softened tap water and dishwasher water are less useful. Salts used in them can damage soil structure, particularly if rich in clay.
However, short-term use of softened water should not cause serious damage and may be worth considering in an emergency.
Mains water usage in homes and gardens is often highest when water availability is lowest – in hot, dry periods.
We are encouraging gardeners to adopt a few simple pledges to make gardens and outdoor spaces thrive by collecting rainwater during rainy spells, and re-using it during dry spells.
The RHS is a charity inspiring everyone to grow via research, advice, outreach, shows and gardens.