Drip irrigation 101
Give water a direct route to your plants
Conserving water doesn’t mean you need to have a scorched-looking yard. In Northern Nevada, we have so many plant species that look great, smell sweet and don’t drink much that golf-course-green lawns are practically going out of style.
If you’ve already selected your water-efficient flowers, shrubs and trees, now all you need to do is plan and install your drip irrigation system.
It consists of a network of tubing and a few pieces of hardware that emit water directly to your plants. Drip systems are far more water-efficient than sprinklers, which can lose up to half the water they broadcast to evaporation and runoff. Drip irrigation can also help curb weed growth and make it easier to grow in tricky spots, such as slopes or windy areas.
The simplest way to set up drip irrigation is to purchase a retrofit kit (about $20), which converts existing sprinkler heads to drip lines, or a hose-bib kit with a timer ($50-80), which attaches to a garden hose. These are good options for renters who don’t want to alter permanently their landscaping, but you’ll sacrifice durability for convenience. The kit systems tend to wear out after a few years.
For a longer-lasting system, you’ll need a vacuum breaker or a check valve (also called an anti-siphon valve), a small plastic device that’s required by law to keep yard water from contaminating your home water supply.
If you’re going to irrigate, you definitely want to automate, so you’ll need a controller or a timer.
“It can go on at times that are convenient for the plants, but not the homeowner,” says Nate Weyant, general manager of Harris Landscape Construction.
You’ll also need an electric solenoid valve (electric or 9-volt-battery powered) to control the flow of water and some polyethylene tubing. Keep in mind that the tubing comes in different sizes, measured in fractions of an inch, that aren’t necessarily compatible with each other. You can purchase adaptors, but planning ahead and using a consistent sizing scheme will save some hassle in the long run. If you’re converting an existing sprinkler system, tubing from a plumbing supply store is more likely to fit your pipes than tubing from a hardware store.
Installing the components isn’t hard, but a little forethought will go a long way.
“The simplest way to assemble them is to lie them on the ground so they emit to plants,” says Weyant. But he recommends going a step further. “Drip tube has to be covered by whatever ground cover you’re using—rock, bark or gravel. The poly pipe is not UV resistant,” he cautions. He’s noticed that heavy doses of Nevada sunlight will cause cracking after about six years.
Weyant adds, “You need a weed barrier anyway, so when you put your fabric down, you can actually staple the pipe on top of the fabric and run it around to your plants.”
According to Alex Willis, product manager at Western Nevada Supply Co., do-it-yourselfers can acquire supplies for a basic drip system for a quarter-acre yard for $400-600.
Landscape contractor Will Johnson says his new company, 2 Crazy Gardeners, can install a system on a quarter acre for around $800-$1,000. For older yards, expect additional labor charges. Weyant points out, “With an older landscape with rooted trees, it’s tougher to dig the trenches.”
It shouldn’t take long to recoup your investment. While water in the Truckee Meadows is a relative bargain, at just $1.58 per 1,000 gallons, the average homeowner uses 137,000 gal a year, about 77,000 of that in the yard. At the current rates, switching to drip could save you a few hundred dollars a year.
Kim Mazeres, director of customer relations for Truckee Meadows Water Authority, notes that the price of electricity and gasoline directly affects the price of water. If the prices of those resources continue to rise, water rates could increase in the fall.
Knowledge is (conserved) power
Before you get started, there are a few things you should know in order to make your switch to drip irrigation easier and your plants happier.
1) Know your soil type. “Soil type completely dictates how water moves through the soil and is held by the soil,” says Leslie Allen, commercial horticulture program coordinator for the University of Nevada Cooperative Extension. This will help you determine exactly how much water you’re going to need to use. But you don’t have to be a geologist to get started. “It’s easy for homeowners to figure out,” says Allen. “Walk into our office. Or call. We offer free, researched-based advice.”
2) Know your evapotranspiration rate. That’s the rate at which plants lose water from evaporation and transpiration (the water the plant emits into the atmosphere). If you know exactly how thirsty they are, you know how much to water them. The Cooperative Extension office can help calculate your evapotranspiration rate, or you can buy a device that does it for you. Pawl Hollis, owner of Rail City Garden Center in Sparks, recently started carrying sensors that measure soil moisture, and he’s impressed with their efficiency.
“When that thing gets wet, it shuts off your irrigation system. It takes into account rain and other things,” Hollis explains.
3) Finally, know yourself. When there’s gardening to be done, are you the sort who’d rather pick up a shovel, or just pick up the phone and call a landscaper? Designing and installing your own system is a straightforward endeavor; it requires no special tools and a little easy-to-acquire technical knowledge. Whether you do it yourself or rely on a professional landscaper, regular maintenance is essential.
“Most irrigation systems need to be drained in the winter so they don’t freeze in this area,” Weyant says. “And you need to be able to shut it down to fix it.”
Your watering needs will change over the course of a season. For trees, you may need to move the emitters periodically so water gets closer to outward-growing roots. You’ll also need to calibrate your drip system’s settings fairly often.
“I would suggest checking every two weeks because the weather changes so rapidly here,” says Allen.