RENO, Nev. –As water bills climb, our lawns look a little more wilted every day.
That's why University of Nevada Cooperative Extension (UNCE) experts are urging people to test their lawn irrigation systems to make sure they are watering evenly and maximizing the effectiveness of the desert's most precious resource – water.
UNCE water quality specialist Sue Donaldson says lawn irrigation – often the biggest water user in the landscape – is “notoriously inefficient,” with as much as 50 percent of the water evaporating in the air or blowing onto impervious surfaces.
“The most common problems with lawn grasses that we see at Cooperative Extension are a failure to irrigate evenly and in the appropriate amount,” Donaldson says.
There are a number of inexpensive things you can do to keep the water on your landscape and decrease water use.
Re-evaluate how much you’re watering. Now that our daily temperatures will be dropping, some of us may need to reprogram our sprinkler timers. If you haven’t reprogrammed your sprinkler timer since the hottest time of the summer, it is probably delivering too much water for the cooler temperatures and shorter days.
Watch the weather. As the weather changes, reprogram your timer. Visit the Washoe County Evapotranspiration Web site at http://www.washoeet.dri.edu for advised watering lengths based on your type of sprinkler heads. If we’re lucky enough to get some rain, check the Web site. Your turf may require less water.
Water in cycles. Split the total watering time into three to five separate cycles. Water in short, 10 to 15-minute bursts with an hour in between each cycle to encourage deep wetting and decrease runoff. Your lawn will appreciate it!
Water in the early morning when it’s cool out. Less water will evaporate in the desert heat.
Observe your turf’s growing pattern. If you’re mowing your lawn more than once a week, something is amiss. Nevada turf grasses naturally go dormant in the summer. If you are over irrigating, or you have fertilized in the summer, you are forcing the lawn to grow when it wants to rest. In our region, it’s stressful on turf to fertilize in the summer. The time for fertilizing, if your lawn requires it, is in the spring and fall. Wait until late September for your next application. You can significantly decrease the need for fertilizing if you allow grass clippings to remain on the lawn after you mow. Aerate beforehand so the fertilizer makes it deep into the turf.
Take a little less off the top. Increasing the mowing height to two and a half to three inches will improve the health of your lawn and decrease how often you mow. If you decide to raise the mowing height, do it over a few mowing sessions. Removing more than a third of the leaf blade in one session can stress the lawn.
Many irrigation systems suffer from one or more common problems:
Poor installation and design. Your sprinkler heads may not have enough overlap to provide even water delivery. One hundred percent overlap is recommended. If water pressure is too low or too high, the system cannot operate correctly. Popup sprinkler heads are designed to work at a maximum water pressure of 30 pounds per square inch (PSI), but many systems run at 80 to 110 PSI. The high pressure causes the water to mist, and much of it evaporates before it reaches the plants.
Inappropriate plants for your site or plants within one irrigation zone with differing water requirements. You wind up applying more water than needed for some plants or not enough for others. Cluster plants with similar water needs together, so you can assign them to the same zone on your irrigation system.
Failure to inspect and maintain the system regularly. Look for system leaks, flooded valve boxes, leaking backflow valves or sprinkler heads that are clogged, broken, misdirected or sunken, and fix them.
“Sometimes simple changes can have a big effect on system performance,” Donaldson says.”For example, changing your sprinkler heads from the typical popups to the newer MP Rotator or other similar products that deliver greater uniformity and coarser sprays can reduce water use by as much as 30 percent. Simply unscrew the old heads and screw in the new heads – it’s that simple.”
It’s important to water your turf thoroughly – just don’t overdo it.
“Your goal is to soak the ground deeply without allowing the water to run off the site,” Donaldson said. “Deep watering encourages strong, healthy roots.”