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Recycling Water for Plants

Rainwater doesn’t look as appealing to us as a bottle of mineral water from the local supermarket, but it sure does to our plants. In fact, they’re not even half as fussy as we are, and will even drink your bathwater...

Our tap water comes out laced with chemicals and minerals. It’s only stuff like chlorine, calcium and fluoride, which our bodies can tolerate. But to a plant, it’s like a mild bleach solution! It’s easy to see the wonderful effect that rain can have on our outdoor plants. But why is this?

Why do plants like rainwater?

Rainwater contains hydrogen peroxide, which helps plants to thrive. Many people use a weak peroxide solution to water house plants, and farmers use diluted peroxide to increase their crop yield. Plants also like the nitrogen present in rainwater. Although almost 80% of the atmosphere is made up of nitrogen, plants can only take it in through a solution. Rainwater also contains other trace minerals and elements that are beneficial to the condition and PH level of the soil.

Some plants, like azaleas, can struggle to survive on tap water, so when the rain is coming down, get collecting!

How can I store rainwater?

You can collect rainwater in just about anything, from watering cans, and mop buckets, to Tupperware and mugs.  You can also pop houseplants outside for a little while in light rain.

However if you’re serious about the benefits of rainwater, you may want to invest in a water butt or barrel, which can hold up to 300 litres of water. You can also find tanks to store up to 2000 litres of rainwater. There’s a great article on the BBC about the best way to store rainwater, where they also mention using rainwater in toilets and washing machines!

It’s best to use collected rainwater as soon as possible to prevent it stagnating (although your soil or compost bin, would probably not complain about a bit of algae!) It’s also rumoured that letting a goldfish take up residence in your water barrels is a great way to keep the water clean, but I can’t say I’ve ever tried this... You can find chemicals, or use bleach to keep rainwater clean, but this then defeats the object of collecting it in the first place. The best thing to do is clean your containers when they’re empty, and keep the water covered and out of the sunlight.

Washing up

What is greywater?

Greywater is the used domestic water that comes from our sinks, baths, dishwashers, and washing machines. Greywater is NOT the water that leaves the toilet, or has come from washing nappies. This is blackwater, and should be kept away from plants.

Grey water contains ‘dirty’ things like oil, grease, skin cells, hair, food, and cleaning products. And while this doesn’t sound remotely appealing, it usually contains nutrients that your plants will soak up happily.

Can I water my plants with greywater?

Greywater is great for your plants! Just be sure that it doesn’t’ contain any of the following things, which could present a danger to plants:

•    Bleach
•    Cleansers
•    Dye
•    Boron
•    Shampoos containing many chemicals

If you plan to use greywater regularly, use biodegradable and environmentally friendly soaps. The Ethical Superstore is a good place to start for these. Buying products which produce healthy greywater, will also be full of natural ingredients which are great for your body! If you’re using greywater to water vegetables, be sure not to get the water on the edible parts of the plant.

Always remember not to store greywater. Use it straight away!