Home & Design

A rotor irrigation system covers a wide expanse of turf.

The Water Source


The Water Source
When a Virginia couple originally installed an irrigation system 18 years ago, their needs were extensive. Their newly landscaped property, with its fresh perennial gardens and turf, required plenty of water. Eventually, however, the gardens became established; today, they no longer require regular watering—but the turf still does. The homeowners’ system had become outdated, using up too much water not only for the health of their plants but also for the health of the environment. Recently, they turned to Mitchellville, Maryland-based Petro Design Build to update their irrigation system. The resulting setup allows them to tend to their property’s now-disparate needs while also acknowledging the pressing need to conserve water.

As the couple discovered, there’s an irrigation system out there to suit every situation. According to Petro’s president, Kathleen Litchfield, the question is as much whether you should get a system at all, as it is what kind to get. “I’m not a big fan unless you’re using it for turf, because it isn’t necessary for established trees and shrubs and it does waste water,” she explains. “If you’re putting in new plant materials, it’s better not to rely on irrigation at all because plants need a more concentrated watering system initially.” Under those circumstances, Petro recommends using a hose to do the job.

However, if you do decide you want to irrigate, the best plan is to use a drip system in the gardens and a spray system on the turf. The drip system is a series of half-inch tubes set 12 to18 inches apart from one another. Positioned just under the surface of the soil, the tubes can be directed at specific plants from root level. “Drips are best for beds,” says Tom Woods, residential irrigation manager for Bowie, Maryland-based Complete Landscaping. “They are more efficient because they water plants at the roots so they use less water. And there’s no waste due to evaporation from sunlight or runoff.” Drips are optimal for some plants, such as roses, that respond best to being watered at the roots. And according to Kathleen Litchfield, the drip system also eliminates fungal growth on plant leaves caused by too much water collecting on them.

There are some downsides, however. Drip tubes require some maintenance; because they sit just beneath the surface of the ground they can become visible and periodically need to be re-covered. And, as Mike Ritgert, irrigation and lighting design manager for Dulles, Virginia-based Chapel Valley Landscaping, explains, it is often difficult for the homeowner to actually tell whether the system is working without going outside to test the soil. “A drips system needs more monitoring and management,” Ritgert says.

Typically, homeowners use pop-up systems for their turf, and though landscapers may discourage it, they often choose them for their beds as well because they require less maintenance than drips. Rotor pop-ups and spray pop-ups both are available; spray from a rotor head reaches 30 to 40 feet and is most often used on commercial-sized lawns, while a pop-up spray head reaches up to about 12 feet—a more common span for a residential property. According to Tom Woods, these systems are more wasteful than drip systems, using 10 to 12 gallons of water per minute, but require almost no maintenance. “Drip materials are a little less expensive, but installing them is more labor-intensive,” Woods says. For spray pop-ups, the opposite is true. Ultimately, Woods estimates that the cost for pop-ups is about 10 percent higher.

Given the varying needs within one yard, most landscapers recommend installing a combination of systems. “When I go out to a property,” says Chapel Valley’s Mike Ritgert, “I talk to the client about having the yard divided into separate zones for irrigating. With irrigation systems you can have a tendency to over-water”—which can be good for turf but overkill for plant beds. Creating zones that can be controlled separately will allow the homeowner to monitor their systems’ water output most effectively.

Whether or not a property is divided into zones, any automatic irrigation system will require a timer to turn the system on and off, called a controller. Controllers enable the system to sense moisture, so that it can detect when to turn on the water. “Controllers can adjust the system to factors like time and climate conditions,” Ritgert says. There are also sensors on the market that read soil moisture for the controller, but Ritgert suggests using them with caution. “They are only so helpful because soil conditions can be so diverse even from the front to the back yard, a sensor is not necessarily accurate.”

Another option is a rain sensor. “Rain gauges on the roof and gutters tell the system not to come on until the weather is dry,” explains Tom Woods. Computerized controllers are also available, working off weather reports on radio or satellite systems. Some use modems or cell phones to enable homeowners to operate them remotely. Alternatively, landscape companies will offer to maintain the system by computer for the homeowner. At Chapel Valley, “we offer the service as part of our maintenance program,” Ritgert says.

Controllers come with a variety of extras which, according to experts, may or may not be worth it. “Don’t use injector systems,” advises Woods, referring to a mechanism that adds chemical fertilizers to the irrigation water. “They’re not scientifically fine-tuned enough and it will be hard to control how much is getting out.”

Before deciding on any irrigation system, be sure to confirm the adequacy of your water source. “If your existing water source is not sufficient, it’s probably not worth the expense,” says Kathleen Litchfield. It’s easy enough to check the water pressure on your property if you have city water, by hooking up a pressure gauge to the hose or spigot outside the house. For a well system, homeowners will need to have the well checked. “Older communities can often have lower pressure,” says Woods. “Also, highly populated neighborhoods where lots of people are sharing the same water source can have the same problem.”

Determined homeowners may choose to install a new well if there is not enough water to support an irrigation system, but this is an expensive alternative, adding up to $7,000 to the cost of the whole enterprise.

Ecologically concerned homeowners are turning to green alternatives as well; Chapel Valley recently buried two plastic tanks on a Takoma Park property to catch runoff. Green roofs and gutters are becoming increasingly prevalent as a way to manage storm water, channeling it into the irrigation system. If the water is dirty or chemically compromised, it’s possible to run it through a water softener.

The total cost of an irrigation system includes plumbing and electricity, as well as “backflow protection,” a safety device that ensures the irrigation water—which flows through a line from the house to the system outside—will never back up into the house (this is required by law in Maryland). Depending on the choices you make—the type of system you want, the level of sophistication of the controller, the sensors and other extras you prefer—the cost of an irrigation system will range widely, from $5,000 to $15,000 for a half-acre lot.

Many homeowners prefer to hire a landscape company to maintain their irrigation system. The company will monitor the property’s needs as the seasons change and regularly check soil and plant health. This may be the best solution: Landscaping a property is a major investment, after all, and homeowners want to make it last. According to Litchfield, having an irrigation company install your system is fine, but it’s important to “hire someone who knows about plant materials” to calibrate the system to the needs of the property.

“Money is a huge factor, but what you really want is for the system to work efficiently,” says Tom Woods. “Get a company that will do maintenance year-round.”


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