By John Pohly, Horticulture Agent, Colorado State University Cooperative Extension
If you are interested in saving time, money or water, you are interested in drip irrigation. The beauty of drip irrigation is that it drips. It doesn't spray or gush, sending a lot of water where it isn't needed. Instead it slowly drips where the water does the most good, thus saving both water and money. And, you save time, because the system works for you.
Drip irrigation systems have come a long way since some ingenious gardener laid pipes, punctured them with small holes and turned water on at low pressure. Some credit drip irrigation to avocado growers, trying to get water to trees on steep California hillsides. Others say the idea originated in Israel. Wherever it came from, drip irrigation has had a big -- and positive impact -- on water-conservation gardening and the growing of crops.
Modern drip irrigation systems can be anything from small plastic emitter devices from which drips emerge to micro-spray systems for flower beds. They also can include flexible porous pipe, that usually is made from recycled car tires and looks similar to a black garden hose. Water seeps out small openings in the pipe between the particles of recycled tire.
Drip systems usually need a pressure regulation device. If installed without such a device, too much pressure can build up in the system and instead of a slow drip, you may get a stream, although not necessarily a flood. In a worst-case-scenario, the entire system could blow out.
If you're planning to install the system on a hillside, you may need pressure-compensating emitters. They will compensate for water pressure differences at the top of the hill (where you would otherwise have less pressure) and the bottom of the hill (where you would have more).
You can purchase drip systems as a kit or buy individual fittings. When purchasing individual parts, the manufacturer usually provides instructions about layout design. Follow those instructions for maximum performance from the system.
The Planning Stage
It's preferable to lay out the system to water plants of similar size and type on the same line. Although it is more difficult, you can use the same line and install more emitters to water large plants and fewer emitters to water small plants.
Consider designing and installing a drip irrigation system for one area and see how it works. If you like the system, you can expand it into other areas. In the meantime, you'll be able to learn from the first endeavor.
Drip irrigation works well in the vegetable and flower garden. If plants are set in rows, you can place a length of porous pipe along the row; water will go to the plant, rather than to the weeds growing between rows. At the end of the season, you can roll up the drip system and store it over the winter. Drip irrigation materials come with a long life expectancy, so you can plan for years of use.
Despite the great advantages of drip irrigation, it has its drawbacks. It doesn't wash dust from foliage. It requires pressure regulation. And, if the system is installed beneath mulch -- an excellent water-conservation technique -- you can't see it working. You know something is wrong only when plants start to wilt.
Photo: Judy Sedbrook
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010