All about irrigation
Keeping your garden looking good while conserving water is easy with the water saving technologies that are built into computerised irrigation controllers. It is now accepted that watering a garden with an irrigation system is more effective and more water efficient than using a hosepipe. An irrigation system will:
A good automatic irrigation system is an ideal for the low maintenance gardener or frequently absent owner as it is a great time saver and, if maintained properly, totally reliable.
When properly planned and managed, it will result in substantial water savings when measured against hand-held or sprinkler-and-hose irrigation. In addition, an automatic irrigation system with a rain sensor will stop any irrigation cycles from starting when rain has fallen, thus saving more water.
Zoning your plants into groups with similar water needs and using different stations of the irrigation system to water these different zones will also reduce your water bill.
Plants thrive on a programme of regularly timed and evenly measured water, so an irrigation system is a shortcut to a beautiful garden.
Manual or automatic?
A manual system is operated with ball valves which can be opened and closed manually to let water into the irrigation system directly from the mains water supply. Otherwise it can be attached to a tap by means of quick-clip connectors. A water timer or programmed mini-computer timer that automatically switches on and off can be attached between the tap and the irrigation pipe.
An automatically operated system can be programmed to water the garden on specifically chosen days and times. To get the full benefit from an irrigation system, an automatic system is recommended as it saves time and will enable watering whilst you are on holiday. It can be programmed to water during off-peak times when water pressure is high, and to give different areas of the garden specified, pre-programmed amounts of water.
Do-it-yourself or hire a contractor?
A simple irrigation system that is attached to a tap and waters a particular area of the garden only is an easy task for anyone to install. You can purchase a kit or buy the system in pieces. So, according to your budget, you can link up a single flowerbed, water a section of the garden or even put pop-ups in the lawn.
However a complex automatic irrigation system is like an octopus. It has a central control with extending zones. Each zone can be programmed to irrigate a particular section of the garden every day, or on alternate days, or once a week, for a pre-determined period of time.
Installing a fully automatic system that is connected directly to the water mains is complicated, so think long and hard before you decide to install a comprehensive irrigation system yourself. Doing-it-yourself may actually prove more expensive in the long run than bringing in a professional irrigation contractor – and it will certainly take longer.
Experienced contractors know where the pitfalls are and will install the most cost-effective and energy efficient system for your garden as they are constantly updated on the latest breakthroughs in irrigation. For example, there are rain or moisture sensors that detect when it is raining and cut off power to the system automatically in order to conserve water. For a list of professional registered irrigation contractors contact the Landscape Irrigation Association of South Africa at www.liasa.co.za or 073 177 5822.
The larger your garden, the larger the spray-radius needed on a sprinkler. There are four basic types of sprinklers, each with a different radius:
- Small-radius micro sprays work well in small townhouse gardens. Micro sprays continuously emit a steady stream of mist or tiny water droplets into your garden. Micro irrigation kits have built-in nozzle filters that avoid blockages. They are also good for seedling beds. Their radius of spray is 0,5-2m.
- Cone sprinklers or static sprays continuously spray in all directions and have a spray radius of 2m-4,6m.
- Small rotary sprinklers use water pressure to produce a rotating motion and have a spray radius of 5m-9m.
- Large rotary or impact sprinklers – where a hammer action causes a rotating motion – have a spray radius of 8m-15m. These are suitable for very large gardens.
Each of the different types of sprinklers offers a range of options. There are pop-ups for lawns, and shrub sprayers for garden beds. Shrub risers are permanently installed in beds.
Position sprinklers so that their sprays overlap by at least 75%, so the spray of one sprinkler overlaps the next one to give uniform water coverage. Any stretching of the spacing will result in an uneven distribution of water between sprinklers.
Sprinkler spray patterns
The shrub sprayers come in a range of spray patterns – 360º full circles, 180º for borders next to walls and paving, 90º for use in corners, and strip sprayers used in long narrow beds or strips of lawn.
Select the spray pattern nozzle according to where you need the water to be distributed. If the sprinkler is in the centre of the lawn, you will need a 360º spray pattern. If the sprinkler is placed against a wall, you will only need a 180º spray pattern. If the sprinkler is sited in a corner, a 90º spray pattern is the right choice. Use strip spray patterns in long narrow beds or strips of lawn.