Getting a Home Sprinkler System Through an Eastern Washington Summer

July in the upper valley is dry, bright and long. A lawn that looked fine in May can go crispy in two weeks if the sprinkler system isn't doing its job. Most summer lawn problems come from small, fixable things: a head that's buried, a nozzle that's clogged, a timer that's set for last spring. Here's how to keep a home system running and how to think about when and how long to water.

Start by running every zone and watching

Don't trust the timer's display. Walk out with it and run each zone by hand while you watch. You're checking for heads that don't pop up, ones that spray in the wrong direction, and spots where water pools or doesn't reach. Mark any trouble with a flag or a stake so you can find it again once the water is off.

Do this early in the season and again in the middle of summer. Heat is hard on plastic, and lawn mowers, kids and dogs all take their toll on risers and nozzles.

Pop-up heads: the usual suspects

Pop-up sprinklers cause most of the day-to-day problems because they live at the surface of the lawn. Grass grows over them and blocks the spray. Dirt gets in the nozzle. A mower clips the top off. Soil settles and the head ends up too low or sits crooked. Most of these have simple fixes.

• Trim the grass back around the head so nothing blocks the stream.
• Pull out the filter screen under the nozzle and rinse off the grit.
• Raise a sunken head by digging around it and adding a little soil underneath.
• Replace a cracked riser or a head that sticks halfway up.
• Adjust the arc and the distance so you're watering the lawn instead of the driveway or the fence.

If you're not sure what's wrong with a head, take it out and bring it to the store. Foothills Irrigation carries pop-up sprinklers and lawn sprinklers, and it's much easier to match a replacement when the old one is sitting on the counter.

What control wire does, and how it fails

The timer sends a low-voltage signal through control wire to a small electric valve for each zone. The wire runs underground, usually in a bundle with one wire for each zone plus a shared common wire. When a zone stops working, wire is often the cause. Shovels cut it. Rodents chew it. Old splices corrode and lose contact.

A simple way to think about the problem: if a single zone is dead and the others work, suspect that zone's wire or its valve. If every zone is dead, look at the timer, its power or the common wire. Waterproof wire connectors make splices last longer than plain twist caps. Control wire and timers are both on the store's lawn and garden list, so you can pick up wire, connectors and a replacement timer in the same trip.

Think about the timer as a tool you adjust

Many timers get set in spring and never touched again. A summer schedule should differ from a spring one, because lawns drink more when it's hot and dry. Look for a seasonal adjustment setting, which raises or lowers all run times by a percentage without making you reprogram every zone.

Replace the backup battery if your timer uses one, so a power blip doesn't wipe the schedule. If your timer is old and hard to program, a newer one is worth the swap, since a schedule you understand is a schedule you'll adjust.

Water deeply, not often

The best way to figure out run time is to measure. Set a few empty tuna cans or straight-sided containers on the lawn, run a zone for a set time, and see how much water landed. That tells you how long it takes to apply what your lawn needs. Different zones throw different amounts, so test the sunny strip and the shaded corner separately.

In general, deeper and less frequent watering pushes roots down, and shallow daily watering keeps them near the surface where they dry out fast. Early morning is usually the best window, since wind is lighter and less water evaporates before it soaks in. Watering in the heat of the afternoon wastes water. Late evening can leave the lawn wet overnight, which some lawns don't like.

Watch the lawn itself. If footprints stay pressed into the grass after you walk on it, or the color turns a dull gray-green, it's asking for water. If a zone stays soggy, cut it back.

Gardens and beds are a different job

Flower beds, vegetable plots and shrubs shouldn't share a zone with the lawn. They need water at different rates, and a lawn spray pattern wets leaves and wastes water on bare ground. Drip is a better fit for beds, because it puts water at the roots slowly. Drip tubing and fittings are in the lawn and garden section at the store, along with hoses, shovels and garden tools for the hand work.

Give the system a once-over every few weeks through the summer, and do a quick drive-by after the lawn gets mowed. A few minutes of looking is cheaper than re-seeding a burned patch in September.