Updated: 20-Jun-2012

Saving Water

Saving Water In The Garden And Greenhouse

It doesn't matter how large or small your garden is, if you like growing plants they do need watering from time to time. As water becomes more scarce this is one area that becomes harder to deal with, coping with hosepipe bans in the summer (and winter?), empty rainwater butts and having to fill numerous watering cans. However there are several ways that you can drastically reduce the amount of water in the garden you use. The same is true for those of us lucky enough to have a greenhouse.

When To Water

The best time of day to water is in the late evening just after the sun has gone down and temperatures are falling. This reduces the amount of water lost due to evaporation.

How Often To Water

If you water plants and bushes too often their roots will remain shallow, weakening the plant. Wait until they show signs of wilting.

Where To Water

Rather than covering plants with a general spray of water it is best to water close to the roots around each plant, it does take more time but means the water is more likely to reach the roots. Don't use a spray on the watering can or hose, concentrate on getting a reasonable amount directly around the roots.

Making Watering Easier

To maximise the amount of water reaching the roots of plants in the garden make a small hollow or indentation in the ground around each plant. The bigger the plant the bigger the hollow. This allows the water to collect around the plant rather than spreading out across the garden. An alternative to this is to put a short piece of plastic pipe (of appropriate diameter) near the plant to just above root depth which can be filled with water allowing the water to reach the roots directly.

With plants in pots make sure the pot is standing on a tray, plate or other water tight container and fill this with water so the water is drawn up into the pot - this has the benefit that less water is lost through evaporation from the soil and the plant roots tend to grow downwards rather than staying near the surface make the plant more resilient to dry conditions. Using experience add only enough water so that the water has all been absorbed into the soil by the morning. It does mean the plant pots need a hole in the bottom to absorb the water through. Another option for larger containers is a length of plastic pipe going to about half the depth of the pot (make the hole first so the pipe doesn't fill with soil) and water the plants through this. Although this method is quite labour intensive to put in place it is probably the most efficient. The pipes do need clearing of soil occasionally.

Reducing Evaporation

To reduce evaporation from large pots and tubs line the sides with bubble wrap. This acts as an insulator and reduces the effect of the sun warming the soil hence reducing evaporation. Use a mulch on the garden around plants where possible again this reduces evaporation.

To reduce evaporation from the garden use mulches such as wood chips, gravel, bark or cocoa shell to reduce water lost by evaporation. This also reduces weed growth, this means water is not being wasted helping the weeds to grow. Doing this saves both water and weeding time.

In The Greenhouse

Cover any tanks used to store water to minimise evaporation but always leave a small gap around the edges to ensure the water doesn't become stagnant if left for a long time.

Example of an automatic watering system that waters the roots not the top of the soil

Make sure the ventilators are opened in hot weather to stop the greenhouse getting too hot which will increase the rate of evaporation, drying out plants quickly. It is worth using a water based shading paint or close mesh netting to reduce the effect of direct sunlight.

Wherever possible water plants from below by standing the containers in shallow trays which can be filled with water. Another option for larger containers is a length of plastic pipe going to about half the depth of the pot (make the hole first so the pipe doesn't fill with soil) and water the plants through this. Although this method is quite labour intensive to put in place it is probably the most efficient. The pipes do need clearing of soil occasionally. The picture opposite show an example of using plastic pipes in a greenhouse. The small yellow tap just visible are used to reduce the flow so that the pipes don't overflow for during the time the water is on.

Ponds

Whether your pond is used as a fish pond or just for decorative purposes there are probably opportunities for save pond water and cut garden water use. Ponds lose water by evaporation and leakage. The first step is to make sure all leakage has been minimised either by using a proper liner or by using plastic sheeting with the individual sheets sealed together. This is a big job but will save money in the long term. If appropriate evaporation can be minimised by growing broad leaved water plants such as water lillys. If the pond has a fountain make sure it is fed from the pond itself rather than the water mains (we have seen a couple of these which obviously waste a massive amount of water). Have fountains on a time switch so that they only run when needed - there may be a balancing act here o stop the water stagnating.