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There’s more than one way to get soaked if you’re a plant.

Marie-CHere’s a comparison of four irrigation systems to help you find ones that suit your garden.

By Mary Lynn Bruny

Are you sick of the endless time-­consuming chore of hand-watering your garden beds? Adding an automated irrigation system certainly makes gardening more enjoyable. There are several options to consider, whether you install a system yourself or hire a landscaper to do it.

Professionally installed irrigation systems have one master programmable control box, usually placed on the inside or outside garage wall, and the system runs off of a designated water supply from the home. Homeowner-installed systems run off the home’s hose bib with a battery-operated programmable timer.

Both professional and homeowner-installed systems can be set up to have different “zones” or garden areas where you can program the watering days, start times and watering duration.

Shrub riser irrigation systems are best for large areas with low plants that have similar water requirements. Photo by www.plantnurserytampa.com
A drip system supplies more water to a particular area, so you can grow thirstier plants in places where you have drip emitters running to trees and shrubs.
Photo by www.plantnurserytampa.com

Each type of system listed below has its own requirement for water pressure (PSI—pounds per square inch) and water flow rates (GPH—gallons per hour). It’s not advisable to mix two systems within a zone with different PSIs and GPHs; you risk damaging equipment with too much pressure or under/overwatering plants. However, it’s fine to use different systems for different zones.

If you’re debating between hiring professionals or installing a system yourself, consider these points: Professional landscapers can buy higher-quality, longer-lasting materials at wholesale establishments than home­owners can buy at retail stores. More significantly, if you install your own system, everything is attached to your hose bib, which remains on at all times waiting for the timer to release water. This makes some homeowners nervous, especially when they go out of town. Will the timer battery fail and the plants die before you get home? Will something break on your hose bib and cause a flood? If you decide to install your own system, another option is to hire a professional to create a design for you to execute. You buy the plan, but supply the labor.

No matter what system you choose or who installs it, the work doesn’t stop after initial setup. “All irrigation systems need some maintenance,” says Becky Hammond, landscape architect at Boulder’s Native Edge Associates and an irrigation expert. “Irrigation systems are a blessing and a curse. They always need a little tinkering at some point. It’s not something you put in and just walk away from for 10 years.”

In the fall, for instance, before freezing temperatures occur, professionally installed systems must be “blown out” (the water drained) to avoid burst pipes and potential water damage within the home. This job typically costs about $75 for a six-zone system. Each spring, every system needs to be checked for adjustments and any needed repairs.

There isn’t a perfect irrigation system, only the one that works best for your garden. “Every system has its pluses and minuses,” Hammond says. “But they are all better than moving around a sprinkler for hours, or having your plants die while you’re on vacation.”

Here’s a look at four common systems:
Shrub riser irrigation systems are best for large areas with low plants that have similar water requirements. Photo by subin Pumsom.
Shrub riser irrigation systems are best for large areas with low plants that have similar water requirements.
Photo by subin Pumsom.

❶    Shrub Riser System
If homeowners are having a turfgrass irrigation system installed, they can use the same system for their garden beds, only here the sprinkler heads are attached atop 18- to 24-inch-high, ¾-inch riser pipes. The water from these elevated pipes can spray wide expanses up to 15 feet away.

Pros: As this system is compatible with the turf-watering system, it can run on the same zone. It’s the least expensive system to have professionally installed and is very low maintenance and durable. Homeowners know the system is working correctly as they can see the water spraying out.

Cons: This system must be professionally installed and blown out before winter. Because it sprays on top of plants, it can promote the growth of funguses or other plant diseases. Weeds and volunteers are apt to grow in bare areas. As plants grow larger, they may block the spray, causing unwatered patches called rain shadows. It’s a one-size-fits-all watering method, because you can’t adjust water requirements for different plants. This system is the least water-efficient; much water is lost through evaporation. Some homeowners find the riser pipes unattractive, and the risers are easily damaged by pets and wildlife.

Best For: Large areas with low plants that have similar water requirements, like an area with low shrubs and ground covers—as well as large properties where the homeowner wants a simple, lower-cost system.

Expert’s Comment: “People like this system at the beginning of a new planting project because they can see where the water is coming out, and if they want to add more plants, they don’t have to make any changes to the system,” Hammond says. “When people start to dislike this system is when the various plants get so tall they block the spray. Plus, every weed seed that lands there gets watered and grows. So there’s a lot of extra weeding that needs to be done.”

❷    Drip or Emitter System
Here, drip emitters are inserted into a ¾-inch lateral line. Attached to the emitters are ¼-inch-wide individual lines that go to the base of each plant. Drips come in several sizes (from 1 to 5 gallons per hour), allowing the installer to customize water flow to each plant. Typically bushes and trees have more emitters per plant. For ground cover or annual areas where broad coverage is needed, there’s a compatible soaker hose—a ¼-inch Agrifim line—with several emitters built into it. Use Agrifim when you have a drip system with emitters to shrubs and trees, and you want a place to plant annuals on the same zone.

Pros: Homeowners or professionals can install this system. It’s the most water-efficient system because there’s virtually no evaporation loss, and many cities offer rebates for installing it. This system allows the installer to customize the amount of water to each individual plant. It’s the most efficient system for deep-watering individual plants. The plant-specific, on-the-ground watering method discourages funguses or other plant diseases, and does not promote weed growth. Additional emitters can be installed as plants are added. It’s an invisible system if covered with mulch, and it’s mostly animal-proof.

Cons: This system is very labor-intensive to install, and adding new emitters requires good hand strength because the installer has to punch holes in the heavy plastic line. Emitters sometimes clog or get knocked off, and weeding tools can punch holes in the plastic lines; homeowners need to inspect the system each spring. Homeowners cannot easily see if the system is working, as there’s no visible water spray. If a homeowner likes to add plants or move them around, drip lines must be added or moved as well.

Best For: Areas where few changes and additions will be made.

Expert’s Comment: “The water pattern from a 1-gallon drip running for an hour looks like a little wet spot on the surface,” Hammond says, “but underground, it’s the size of a balloon. It’s wider, bigger and very deep. Trees and shrubs like it, because they receive water very slowly at their roots, and it doesn’t evaporate. Commercial properties generally use drip systems because they don’t want to weed a lot.”

❸    Microjet or Microspray System

Microjet risers can spray water anywhere from 2 to 24 inches. They’re best for areas with similar shallow-rooted plants, such as ground covers or annuals, and those with different watering needs like vegetable gardens.  Photo by Becky Hammond.
Microjet risers can spray water anywhere from 2 to 24 inches. They’re best for areas with similar shallow-rooted plants, such as ground covers or annuals, and those with different watering needs like vegetable gardens.
Photo by Becky Hammond.

Here, 8- to 10-inch-tall risers run off a ¼-inch pipe from a lateral line. The risers have nozzles that can adjust the spray from 2 to 24 inches. Some risers have on/off knobs. Although microjets have the same PSI as a drip system and are often used in conjunction with it, microjets release water much more quickly. If homeowners use both systems together, they should increase the recommended emitter sizes to offset this difference.

Pros: Homeowners or professionals can install this system. Nozzles can be adjusted to cover smaller or larger areas, and one riser can water a few plants. Additional risers can be added as needed. Homeowners can turn off nozzles when they don’t want water in an area. The system is more water-efficient than the shrub riser system.

Cons: The risers are easily twisted, pulled out or damaged by pets and wildlife. The nozzles often clog and need to be replaced. Some homeowners find the risers unattractive. This system is not as water-efficient as a drip system, nor does it deep-water individual plants as well. As it sprays on top of plants, it can promote the growth of funguses or other plant diseases. Like a drip system, adding new risers is not an easy task; hand strength is needed.

Best For: Areas with similar shallow-rooted plants, such as ground covers or annuals. Areas with different watering needs throughout the season, such as a vegetable garden. For example, when growing cold-season vegetables, the homeowner can turn off risers in areas where warm-season vegetables will grow later.

Expert’s Comment: “I’ve taken out a lot of dead shrubs that had microjets watering them. They were only getting a little bit of water on the surface, but it wasn’t doing them any good,” Hammond says. “Squirrels and raccoons figure out there’s water in the risers and start messing with them. I swear raccoons do it just to entertain themselves.”

❹    Netafim System
This system uses brown ½-inch-diameter soaker-hose tubing. It’s laid on the ground in a grid pattern about 2 feet apart in beds, and can be more densely placed around large shrubs and bushes. The hoses sit atop the soil and the water slowly oozes out, evenly distributing water across the surface.

Pros: Homeowners or professionals can install this system. It’s flexible and easy to install and adjust. It’s extremely durable and needs little ongoing maintenance. Its color is very unobtrusive. Homeowners can see if it’s working. The system is fairly water-efficient; only the drip system is better. The on-the-ground watering does not promote funguses or other plant diseases. Homeowners can add or move plants wherever they want, as the water is fairly evenly distributed.

Cons: The hoses often get in the way of planting. Weeds and volunteers are apt to grow in bare areas. Plants must have similar water needs.

Best For: Somewhat densely planted areas where the homeowner wants to add and move plants.

Expert’s Comment: “Some professional landscape firms are moving away from drip systems to Netafim systems, as they are so much easier to install,” Hammond says.

Netafim systems are becoming more popular. They’re easier to install and adjust than drip systems, but not quite as water efficient. Photo by www.netafimusa.com.
Netafim systems are becoming more popular. They’re easier to install and adjust than drip systems, but not quite as water efficient. Photo by www.netafimusa.com.

DIY TIPS

Landscape architect Becky Hammond offers the following tips for homeowners who want to install their own irrigation system:

  • Don’t buy materials or build anything until you’ve done quite a bit of research. Check out helpful online sources such as www.gardengirltv.com and www.dripirrigation.com.
  • Don’t get overwhelmed trying to do an entire drip-system installation in one season. Instead, add a new area each spring. See “Go Ahead, Be a Drip” in the summer 2011 online issue of Boulder County Home & Garden Magazine at www.homeandgardenmag.com for DIY drip-system installa­tion instructions. Unless you’re watering annuals, don’t water every day. Plants need to dry out between waterings.
  • Don’t overload a system or risk making it ineffective from lack of pressure.
  • You get what you pay for. Buy high-quality products that will last. Avoid using thin-walled pipe that kinks easily, which will stop water flow.
  • If plants have droopy yellow leaves that don’t fall off, they’re getting too much water. If plants have crunchy dried-up leaves that fall off, they’re not getting enough water.
  • If you want to add a zone for potted annuals that you water daily, buy a two- or three-program controller that gives you more flexibility. “Today’s digital controllers come in two-program or three-program models,” Hammond notes. “Each program dictates what days the zones on that program run, and how many times in a single day. Sod is watered three to four times a week; xeric shrubs twice a week; and annual pots every day. So they each need their own program for the most efficient water use.”

—M.L.B.