Irrigation Notebook: June 2000, Drip Irrigation

No new, radical technology, drip irrigation is an effective, beneficial system that dates back to ancient times. Drip was even used in the Hanging Gardens of Babylon, where porous containers of water were hung over gardens to slowly drip over a long period of time, according to Kathleen Baldwin, vice president, Olson Irrigation, Santee, Calif.

In modern times, drip irrigation’s use in the landscape has been driven primarily by the issue of water conservation. Many contractors and homeowners have turned to drip during a crisis situation, such as a drought, only to find out just how easy, economical and beneficial it can be, Baldwin noted. "Increasingly, drip is almost a household word, especially in areas like California and Florida, where water is an absolute necessity and in short supply," she said.

Drip irrigation is suited to practically any landscape application, according to Kurt Maloney, director of marketing and sales, landscape division, Netafim Irrigation, Fresno, Calif. "There’s hardly any area that couldn’t be drip irrigated," he said. From shrub beds and median strips to trees and smaller turf areas, drip is suited for almost every application imaginable, Maloney noted. "You can cover any shape and any area."

Mike Astram, owner, Northern Designs, Milford, Conn., however, wouldn’t recommend using drip irrigation on a large turf area. "I wouldn’t do a soccer field with it," he said. "If you have a problem, how do you fix it? Drip irrigation would have to be spaced 12 inches apart with a drip tube every 12 inches," he said, noting that a large-scale application such as this would be too much of a maintenance headache for most landscape contractors.

Drip irrigation is now almost a necessity in commercial applications, Baldwin noted. "Drip is much less intrusive than a conventional irrigation system. You don’t even know it’s there, and you can irrigate while business is going on as usual," she said. "You’re also not as apt to have damage done by people kicking in or breaking off heads."

MANY PROS AND A FEW CONS. Drip irrigation provides many benefits, the most obvious of which is saving water. "The water conservation issue is so big we hardly even mention it," Maloney pointed out. "It’s easily understood."

Drip systems make highly efficient use of water, Astram said, who noted that he’s a big proponent of drip irrigation with his customers. "With the type of water shortages that we have, we’re really trying to push this."

Since they’re installed below ground and don’t use sprinklers, drip systems are unaffected by wind or water evaporation issues. Running at low pressure, they also require less water to operate than a conventional system. "You don’t need large quantities of water with drip," Astram said.

Baldwin agreed, noting that depending on such variables as soil and weather conditions, water savings with drip can range anywhere from 10 to 60 percent compared to a conventional system.

Another benefit to drip is that, in contrast to a conventional system, the window of time for irrigating is unlimited since contractors don’t need to worry about spraying passersby or buildings, Astram pointed out.

Drip irrigation also reduces the chances of weed germination, said Baldwin, who noted that when water is haphazardly distributed out of a sprinkler, seeds are more easily germinated, causing weed growth and possibly spreading water-borne diseases. With drip irrigation, though, "you get precise control of water," she said, pointing out that less fertilizer may even be required since the water goes right to a plant’s roots. Drip irrigation’s most apparent drawback is the fact that it’s unapparent – a contractor can’t readily tell if a system is functioning properly. "You can’t tell from a quick look if a system is working or not," Baldwin said. "Because contractors can’t see
the water, they often think the landscape is not getting enough."

Astram agreed that this is a particular challenge. "With drip, you don’t have a visual confirmation," he said.

Unlike a conventional system that is simple to visually check periodically, with drip, a contractor must diligently monitor the system and soil moisture levels on a regular basis. Otherwise, "a problem is not always obvious until a plant shows signs of stress. You could have a plant wilting before you know something is wrong " Baldwin said. "But usually something will give you a clue."

Above all, she advised landscape contractors to "have a little faith," she said. "Just because you can’t see the system working doesn’t mean than it’s not."

Working with drip does have a few other drawbacks, depending on whom you ask. A drip system often has more components than a conventional system, which some landscape contractors find irksome. "Some contractors just don’t want to deal with so many bits and pieces," Baldwin said. "They think it’s too much trouble, that there’s just too much to keep track of compared to a conventional system."

Being too complicated is a common misperception drip has faced from the landscape industry. Another is the notion that drip is too much of a maintenance hassle or costs too much.

All of these perceptions are generally inaccurate or exaggerated, according to Astram. "A lot of people think drip is more expensive, more labor intensive and higher maintenance than a conventional system, but it’s not," he said.

Changing minds about drip, however, is a matter of education and getting accurate information out to the industry, he said.

DRIP TIPS. For a drip system to work properly, there are several considerations to keep in mind. Drip requires low water pressure in order to run and operates at a slower rate than a conventional system, said Baldwin. With drip, contractors must think in terms of gallons per hour as opposed to gallons per minute, she added. "It’s a longer run because the application is slower."

In addition, using clean water is essential, since emitters and other system components can get clogged. Baldwin advised checking components on a fairly regular basis to make sure everything is in working order.

When installing tubing, contractors should put it at least a few inches below grade and cover it with mulch, Astram advised. Otherwise, "anyone working in the bed can catch the tube with a rake," he warned.

Baldwin agreed with the importance of installing a drip irrigation system at the proper level. "If you bury the system, damage isn’t a real issue. There’s very little that can go wrong," she said. "If you install it above ground, however, someone can kick out the tubing or a dog running through the bed can pull it up," said Baldwin, speaking from personal experience.

Overall, drip is easy to install, according to several irrigation experts. "There’s not a huge learning curve. It takes about an hour to learn," said Baldwin, who noted that she installed her drip system at home without any complications.