Growing veggies with grey water
Grey water is waste water collected from the shower, bath, hand basin and washing machine. It can be collected in buckets, or directed from the bath or washing machine onto the garden (laundry to landscape) to be collected in a tank and pumped into the garden.
How suitable is grey water for veggies?
Grey water contains soap, shampoo or detergents from the washing machine that are generally alkaline, which affects the soil’s pH. Vegetables are very sensitive to soil pH, with the optimum pH range between 5.5 – 6.5. High levels of alkalinity can affect the plant’s ability to take up nutrients from the soil, and there may also be a deficiency of minerals that could lead to chlorosis (yellow leaves). If you want to use grey water on veggies, change your detergents to eco-friendly ones that are bio-degradable, have low or no sodium, sodium laureth sulphate (foaming agent), chloride or boron.
Are grey water irrigated veggies safe to eat?
Grey water can contain pathogens (bacteria). To be safe, use grey water on vegetables that will be peeled or cooked. Always wash vegetables thoroughly in fresh water before cooking. Some gardeners don’t use grey water on leafy vegetables like lettuce or radishes, which are eaten raw. If irrigating tomatoes with grey water, just water the base and don’t wet the leaves or fruit, which is common practice anyway.
Most suitable veggies for grey water:
Squashes, melons, brinjals, tomatoes, green beans, runner beans, beetroots, carrots, onions, sweetcorn, broccoli, peas and parsnips.
Lettuce, radishes, herbs, Swiss chard, cabbages, sweet peppers and chillies. 5 grey water-wise tips
• Dilution is the solution, using municipal or rain water. Either dilute the grey water or water your garden occasionally with fresh water to help flush away any build ups.
• Use mulch as a natural filter. Animal manure and compost that includes coffee grounds can help combat alkalinity as well.
• Build healthy soil and the microorganisms will break down many of the pathogens that could be in grey water.
• Don’t store grey water for longer than 24 hours, as harmful pathogens can develop.
• Don’t use washing machine water from a wash of clothes or nappies that were soiled by faeces, and don’t use grey water if anyone in the home is suffering from an infectious disease.