Give Your Drip Irrigation System a Tune Up - June 18, 2008
Jeff Schalau, Associate Agent, Agriculture & Natural Resources
University of Arizona Cooperative Extension, Yavapai County
Drip irrigation systems can be especially problem-prone after five or six years. This is about the age when mineral deposits can start to limit the systemís performance and when trees and medium to large shrubs may need more drip emitters. Often, the first sign of drip irrigation failure is a dying plant. Giving your drip system a tune up will likely improve your irrigation efficiency, conserve water in your landscape and produce healthier plants.
A landscape or garden is considered "irrigated" when an adequate amount of water is supplied to the root systems of plants to provide for proper growth and maintenance. Roots do not seek water. Roots develop where there is soil and periodic water. Deep less frequent watering encourages deeper roots and more robust plants. Rooting depth has limitations because roots also need oxygen and the deeper you go in the soil, the more difficult it becomes for oxygen to diffuse into the soil.
Drip irrigation has several advantages which include: less evaporation and run-off because water soaks directly into the soil; less evaporation and run-off because water soaks directly into the soil; less stress on plants because soil moisture remains relatively constant; reduce weed growth because water is only applied where plants are growing; and reduced water use because its applied directly at plants' roots where it is needed. Of course, this assumes proper system design and routine maintenance.
To begin giving your drip system a tune up, check to see if you have a filter. If so, disassemble, clean and reassemble the filter. Then remove the end cap(s) and turn on the valve allowing the water to flush out dirt and debris in the main line. Turn off the valve, replace the end cap and flush the lateral lines for another two or three minutes. Replace emitters and run the system, one valve at a time, to check for problems. This procedure should also be followed anytime repairs are made to the system.
During the growing season, periodically check and clean emitters for proper operation. Clean the filter more often if using well or ditch water and less often if using municipal water. Check for emitters that have popped off tubing because of high pressure, and install a pressure regulator if needed. Check to see that all emitters are in place. Salt/mineral deposits and be removed from emitters by soaking them in vinegar and/or using forced air to blow them out.
Missing and broken emitters will need to be replaced to keep your system running efficiently. Also, look for pinched or broken tubing and straighten or replace it. Volume delivered can be checked by placing the emitter in a container and measuring the volume after a known time interval.
It is also a good idea to assess whether or not the drip system is adequately providing water to larger plants. Large shrubs and trees are almost always planted with one or two drip emitters placed near the base of the plant. Many sources recommend that emitters be moved outward as these plants grow. I recommend that emitters be added rather than moved. When emitters are simply moved, the roots that were established in the original placement may not get adequate irrigation while you are waiting for new roots to grow toward the new emitter location. In my opinion, drip irrigation can be problematic for these larger plants unless plans are in place to expand the area irrigated over the life of the plant. Multiport drip irrigation heads can accomplish this very well.
Next, you should critically assess whether or not a particular plant still needs irrigation. Native and drought-adapted plants are often established after two years of irrigation and may perform adequately without supplemental irrigation. Cacti and succulents are especially drought tolerant. When emitters are removed, install plugs designed especially for this purpose.
The University of Arizona Cooperative Extension has publications and information on gardening and pest control. Note: Master Gardeners will not be available for walk-in clients in the Cottonwood office for a few weeks due to a lack of office staffing. You may still call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at firstname.lastname@example.org. We apologize for this inconvenience. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/.
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