Irrigation design is about choosing the right equipment for the space you’re looking to irrigate. Some situations might call for sprinklers, and others might be better suited for drip line. While some industry pros may be hesitant to incorporate drip line into their designs, there is consensus among irrigation experts that drip line is effective, efficient and, depending on the situation, can be the best way to irrigate plant material.
“If you chose not to use it, you’re doing your customer a disservice as far as getting that nice, even coverage on the plant material and just wasting water,” says Jean Singleton, CIC, CID, CLIA, and president of Naturescape Irrigation in Cary, Illinois. “There are better choices to be made depending on the situation.”
According to John Watson, CIT, owner of All About Irrigation in Atlanta, drip irrigation is backed by millions of dollars of technology.
“It is used in commercial and residential applications, as well as agricultural applications,” Watson says. “It’s got a lot of technical knowledge behind it.”
Some industry pros overlook or don’t fully understand the benefits of drip line. According to one industry professional, drip has a major drawback that leaves customers and less-experienced irrigation professionals feeling a bit skeptical.
“People like to see the water running,” says Jim Borneman, a consultant with Ewing Outdoor Supply in San Jose, California. “They like to see the visual, and with a dripper, all you see is a little wet spot. You don’t understand how much water is being delivered to the plant.”
The drip difference
Watson says drip line comes in a few different forms. One is comprised of drip tubing with emitters evenly spaced every foot to foot and a half, depending on manufacturer. Drip can also be installed with solid drip pipe outfitted with emitters at strategic spots along the tube.
“Emitters have a certain amount of water that will come out and you add the number of emitters you want around the plants,” Watson says.
Singleton says the benefits of drip line are especially obvious in an application like hedges. When sprays are placed in front of a line of arborvitae, the plant in front of the spray receives all the water, and the plants on either side might also grow well. But Singleton says that the plant growth typically speaks for itself, and it is clear the water isn’t getting to plants farther down the line.
“With an arborvitae hedge used for screening, the best way to get even coverage for the trees is through drip line,” Singleton says. “You can tell a difference in how plants mature when they are all getting the same amount of water.”
While the concept of drip is similar to sprinklers or microsprays, there is one major difference between drip and other methods of irrigation, and understanding that difference is key to using drip effectively.
“Drip is totally different than your typical irrigation because it is measured in gallons per hour. Regular irrigation is gallons per minute. Never should you mix them both.”
– John Watson, CIT, All About Irrigation
“Drip is totally different than your typical irrigation because it is measured in gallons per hour,” Watson says. “Regular irrigation is gallons per minute. Never should you mix them both.”
That means that drip zones will need to run for longer intervals to deliver the same amount of water as a sprinkler zone.
“It’s a low, slow application of water at a low pressure,” Borneman says. “A lot of people don’t understand the complexity of a low volume irrigation system in the landscape. It is much more complicated to do well than a traditional overhead turf irrigation system.”
A green solution
When it comes to water conservation, drip line is top-notch for its ability to deliver water exactly where it’s needed, says Watson.
“Drip became a lot more precious when there was a water shortage,” Watson says. “It’s a green avenue.”
The ability to target water delivery, and to avoid watering the spaces in between plant material, makes watering via drip more thoughtful and discriminate.
The ability to target water delivery, and to avoid watering the spaces in between plant material, makes watering via drip more thoughtful and discriminate.
“With drip, because each emitter is pressure compensating, you can get very accurate with the size of plant material that you’re watering,” Singleton says. “If I’m doing a small shrub, I won’t want as many emitters as around a maple tree. Within that same zone, I can give the maple tree a lot more water and won’t drown my azalea. It is nice to be able to modify the drip within the same zone. I can time it all the same, but because I’m using so many emitters per plant, I can really dial in what each variety of plant in that zone is getting.”
However, drip’s ability to conserve water is dependent on installation and application.
“It can be beneficial to the environment, to plants and to the cost of operation, but it can also be a waster if it’s not installed properly,” Watson says.
Drip should be installed to target water so it can percolate down into the root system, Watson says.
“There is a certain part of the industry that uses it because it is easier and quicker to apply, and because of that, they are leaving out all the parts that make it harder to apply, which is running solid pipe between plants if you’re using emitted pipe,” Watson says. “Some will buy a big roll of pipe with emitters and wrap the whole area. That application takes away the benefits and is watering the weeds in between the plants. The whole idea of drip is to water a specific area at a specific water rate as needed for the material so it can percolate into the ground in that specific area, and anything other than that is taking away the principles of drip.”
Drip maintenance
While drip is extremely effective and efficient, there is one challenge it presents to homeowners. While malfunctioning or broken sprinkler heads are a bit more obvious, realizing that there is a problem with drip line can be more of a challenge.
“The downfall is that customers don’t know it’s not doing its job until they start seeing plant failure,” Watson says. “It requires a more visual type of maintenance where customers have to turn it on and go out and walk to make sure they don’t have any failure in the pipe itself.”
According to Singleton, no irrigation system is maintenance-free, and there are always repairs that will need to be done. For sprinkler systems, that might mean replacing sprinkler heads that were destroyed by snowplows or lawn maintenance equipment.
With drip line, that maintenance most typically includes repairing tubing, as during hot, dry spells squirrels, chipmunks and gophers seeking water will chew through drip line tubing to reach the water inside.
“The maintenance is about the same with sprinkler or drip and really depends on where the placements are,” Singleton says. “If you have landscapers who are coming in and cultivating, we’ve had them make absolute Swiss cheese out of drip lines.”
Everything grows
According to Borneman, the long-term success of a drip system requires the knowledge that as plants and trees grow, their water needs change. That means that a drip system will need to be designed with the capacity to grow and change along with the plant material.
“If you plant a tree, its water demand increases exponentially as it grows, and people often don’t consider how much water that tree might need at maturity,” Borneman says. “Every time the diameter of the tree or shrub canopy changes, the leaf surface area changes exponentially.”
Failing to consider growth and increasing water needs means that as the plant gets larger, the water supply will continue to shrink.
“The tree is the most valuable asset in the landscape,” Borneman says. “You have to match the application rate of the drip to the demands of the plant materials, and that is rarely done.”
There are resources for calculating water needs of any given plant or tree, including grower’s websites and the Water Use Classification of Landscape Species database from the California Center for Urban Horticulture. Those resources can be very useful in designing a system that will be effective long term.
“You can’t arbitrarily add more emitters to support a tree,” Borneman says. “When you mindlessly add emitters, it can overwhelm the hydraulics, the pressure drops, and you have no idea how much water you’re getting.
Out-of-the-box applications
While drip line is ideal for irrigating trees and shrubs, it can also be effective for high growing perennials, as long as they are in an area that won’t be cultivated. For those looking for out-of-the-box watering solutions, drip can also prove useful.
“We’ve been using them in raised garden beds,” Singleton says. “There is tubing with 6-inch spacing between emitters which is nice for a garden bed, because you get a little tighter between the emitters.”
Singleton says drip line also works well in flowerpots and hanging baskets.
“If it is too big to put in flowerpots, we use micro drip line, which is great to curl around,” Singleton says. “Customers love having flowerpots watered automatically; there is nothing better.”
For use in hanging baskets, Singleton says she will run tubing along eves, then bring the tubing down the hanging wire and into the pot.
“We can find a way to water anything,” Singleton says. “The key is, you don’t want to see irrigation. You don’t want to see sprinkler heads and you don’t want to see drip line. It needs to be invisible to the eye.”
