Saving Water in the Garden

Most of the time the majority of us ignore the water around us - a seemingly limitless supply is available cheaply just by turning on a tap. However, that tap water is something we should not just take for granted, and certainly shouldn't waste. Whilst water is recycled indefinitely via rainfall, rivers and seas, the water we get from our taps is a processed commodity. It has been filtered, treated with chemicals and pumped around the country - all of which require energy and resource use. By reducing our demands on tap water, we can chip a tiny bit off our carbon footprint, whilst helping to create a more sustainable lifestyle and save money.

Water is a vital element in the garden - without it your plants will simply die. So it makes sense to make the best use of it that you can, and if possible reduce your reliance on tap water. At this time of year many people will also be considering weeks away on summer holidays, so we also need to consider how to ensure our plants don't run dry whilst we're off enjoying ourselves.

Water Butts

First, we can look at using water sources other than clean tap water in the garden. Plants are less fussy than us, and so don't really need the treated potable water from the mains. They're quite happy to drink up less processed sources of water, such as rain. Water butts are readily available in garden centres, DIY stores and from internet retailers, and allow you to capture rain water from gutters that would otherwise just disappear down the drain or into soakaways. Plumbing them into your down pipes is an easy DIY job that usually takes less than an hour, and then you can harvest several hundred litres of water from a relatively few hours of rain. Water butts can also be connected together to increase your overall capacity or to allow other butts to be placed closer to plants. More or less any roof can provide rain water run off that can go into a water butt - we've got them from a main house roof, a front porch roof and even a little allotment shed roof (which actually has three water butts connected to it!).

If you get a water butt with a tap at the base remember to raise the butt up so that you can get a watering can under it. You can buy purpose made stands to do this, or construct your own stand from reused breeze blocks, pavers or bricks. If you do it yourself please ensure that the base is stable and that children can't pull the butt over onto themselves as a full water butt is very heavy. Securing the butt to a wall can help if that is an issue for you.

Collecting as much rain water as you can during the times of plenty is a good idea, because you will soon find that the level in the water butt starts to drop alarmingly after a week or so of hot, dry weather in midsummer. Luckily, you can augment your harvested rain water with another source of water...

Grey Water

Grey water is the name given to tap water that has already been used once. This can include bath water, water from showers or wash basins, washing up water and water used to boil veggies. In fact the only real exception in most homes is the water that has been used to flush the loo. This is known as black water and it can carry harmful bugs and bacteria, so has to be treated properly before the water can be reused.

Grey water collecting can range from a free and simple use that anyone can do, to complex systems to capture and reuse every last drop. For example, everyone can use a washing bowl to do the dishes in, and then empty the dirty water round their roses.

On the more complex side, some people divert the waste pipes from baths and sinks into large water butts and then use this to water the garden. Some even install pumps (run by solar panels!) to push some of the grey water up into upstairs toilet tanks so that it can be used to flush the lavatories around the home. This obviously takes a bit more effort but it does allow you to cut down radically on your water usage, especially if there are several people living in one house.

The one major difference between grey water and rain water when used in the garden is the length of time that you can leave it to stand in the water butts. Rain water has relatively few impurities in it; mostly just bits and pieces washed down from the roof and gutters. Grey water on the other hand can contain detergents, skin flakes, dirt and food particles. If these are left in a water butt for more than a few days they can start to smell, so it pays to use grey water as quickly as possible. This also means that if you collect grey water in a water butt you should really keep this separate to any rain water fed water butts.

Grey water isn't so good for acid loving plants, as it is effectively just tap water with bits in. Be careful not to spray grey water containing scented soap residues over leafy vegetables either - lettuce tasting of Lush products isn't a taste sensation to repeat! It's fine for fruit bushes, trees, tall veggies and ornamental plants though.

One Step Further...

Whilst many people with water butts are happy just to fill a watering can from them, you can also be more adventurous if you don't mind spending a few more pennies. Water butts can have pumps fitted to allow hoses to supply water to irrigation dripper systems that water the soil around plants directly.
The addition of a small water computer means that watering your plot can almost be left to run on autopilot! This is handy if you have a hectic lifestyle, if your plot is large or if you want to make sure that the crops get watered whilst you are on holiday.

When and how you water can also make a big difference to water usage. The very worst thing to do is to leave a sprinkler on during the middle of the day - much of the water will evaporate before it gets near a plant, you'll also be watering bare soil and weeds, water that lands on delicate leaves can act as a magnifying lens, causing the sun to burn them and, finally, the water will only soak into the top few centimetres of the soil, so plants will grow their roots up near the surface to take advantage of this and thus be more susceptible to drying out when water is not available.

A better bet is to water individual plants directly towards their roots, preferably either early in the morning before the sun gets too hot, or in the evening when the sun is setting. You can do this with a watering can, a hose with a gun on the end or the directed irrigation drippers mentioned above. Try to give the soil around the roots a jolly good soaking, so that the water penetrates deeply into the soil. This will encourage most plants to send their roots deeper down into the ground searching for the water, which can make them more resilient to droughts. Some people use inverted pop bottles with the bottoms cut off or old broken flower pots sunk into the soil to help direct water downwards - just fill them up and let the water soak away into the ground.

Mulches

Another trick to help conserve water is to make use of soil covering mulches. Of course they can also have other benefits such as helping to suppress weeds, providing organic material and habitats for worms and bugs, and reducing wind based soil erosion. Mulching materials can be purchased from garden centres and DIY stores, but you can also reuse organic material yourself for free.

For example, shredded hedge and tree prunings laid about an inch thick make a great mulch that soon weathers into an attractive layer resembling the expensive bark/wood chippings that you can buy. Opened out cardboard boxes, newspaper laid several pages thick and shredded paper can also be used as free organic mulches. If your compost bins are getting full, you can make space in them by using some of the partially rotted material as a mulch (although this isn't quite so attractive - fine for a practical allotment plot though!). It will carry on decomposing on the ground and will eventually get incorporated into the soil.

If you find you're pulling up lots of weeds around the plot you can also just lay these over the soil surface - they'll dessicate in the sun which will help to kill them but they will also act as a mulch. You get multiple benefits by doing this: removing the weeds reduces competition for water and nutrients in the soil, the mulching effect reduces water loss and further weed seed germination, and finally the dead weeds with eventually rot down improving the soil quality. Winner!

When laying a mulch down, you need to ensure that it doesn't actually touch the stems of plants - leave a small bare patch around the stem to help prevent it from rotting and try to aim for a depth between 0.5" to 2".

So hopefully those ideas will help you save some water around the house and garden and perhaps help your plants to survive any dry spells we might get this summer.

Assuming we get a summer this year of course...

Jim'll

Allotment photo (c) Salena Walker 2010 

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