Art of watering
Watering gardens and landscapes during the summer in the Inland Northwest is a necessity. Our summers are traditionally dry with some areas receiving well under an inch of rain a month during July and August. That’s not enough to keep a bluegrass lawn happy for even one week. It gets so arid around here that even drought tolerant plants and grasses need supplemental water during the driest parts of the year.
Garden watering has come a long way from the days of the Rain Wave and hose. While it was fun to run through the sprinkler and watch it shoot high in the air, times have changed. Our landscapes have gone from fairly simple lawns surrounded by shrubs and trees with a house planted in the middle, to more sophisticated recreations of natural scenes sometimes complete with rocks, water features and plantings of many different types.
These shifts in landscape design have also brought other changes few gardeners predicted. Years of drought in the Western U.S. – including in our region – have left water reserves low. Rapidly growing populations all across the West are putting a drain on water resources. Let’s face it, other than the esthetics of a lush green yard, watering landscapes is really a non-essential use of the precious resource clean drinkable water has become.
“There is a lot of work ahead of us educating the public, government agencies, municipalities and school districts (on using water wisely),” says Todd Watson, president of Auto Rain, one of the region’s largest suppliers of sprinkler equipment.
A new garden water ethic
Even though we had near-record rains in the spring, watering landscapes and gardens for many Inland Northwest residents is going to be a major challenge this year and in the future.
By some national estimates, 40 percent of household water use goes to our yards. Many cities around the country and the world have put restrictions on how homeowners can water and what they can plant to conserve municipal water supplies. Even supposedly rainy Seattle and other Puget Sound communities have put watering restrictions in place and mandate how landscapes are managed. The threat of water shortage is not going to disappear.
In the Inland Northwest, we haven’t addressed these issues much. But our time is coming and it may be sooner than we think.
“We can guarantee ourselves at some point, five, 10 or 20 years down the road, we will have a problem. So why not be proactive?” says Watson.
How much and how long to water?
They’re two of the biggest questions homeowners have about using sprinklers. There are several factors that affect this decision.
First, your soil type will have a big influence on both how often and how long you need to water.
“If you have sandy soil, you are going to have to water longer and fertilize more often,” says Wes Kemper, assistant manager for Auto Rain. “If you have rocky or clay soil, you are not going to water as much.” Clay soil accepts water slowly and retains it longer. Sandy soil accepts water quickly and the water drains away quickly.
Second, the type of sprinkler heads you have has an enormous effect on how long you have to water. Fixed spray heads spray a solid pattern over an entire area. That means the entire area gets the same amount of water for the same amount of time. Rotor heads put out a stream of water that hits only one area as they turn, which means it takes longer to put down the same amount of water as with a fixed head sprinkler.
Third, sprinklers apply water at different rates depending on the size of the nozzle and the water pressure that drives it, so it’s very important to know how much water they put out.
Lastly, remember that water requirements can vary quite a bit within an individual landscape. Shady places will require less water than areas in full sun. Individual varieties of plants have different water requirements.
Drip – don’t sprinkle
Drip irrigation is just that: It delivers a small amount of water slowly directly to the roots of plants.
The biggest challenge when setting up a good drip system is getting the right size and number of heads to meet the specific plant’s needs.
The flow of drip emitters is measured in gallons-per-hour (gph) and the emitter is usually installed at or just below the soil surface. This reduces water lost to evaporation and can lower overall water usage by 40 to 70 percent over conventional sprinklers.
“You won’t get all the weeds,” says Kemper. “You are watering just the plant you want watered.”
Kemper recommends using a single 1 gph emitter on perennials, and one or more 2-4 gph emitters on average sized shrubs. Small trees need 4 gph emitters, while larger trees may need several 20 gph bubblers. As plants grow, it will be necessary to increase the dripper volume or add heads.
Drip systems should be run for longer times than other sprinklers to get the proper volume of water to the plants. Sometimes they have to run for hours.
Miniature spray heads and micro misters have been developed to allow you to water a slightly larger area than a normal drip head. This works well where groupings of plants would be more evenly watered by a small spray than a drip head.
There are even drip systems available specifically designed to water hanging baskets and pots on decks and patios. No longer do you have to rush out on a hot day to check your pots. Your multi-stage controller box merely turns on the drip system as needed and the job is done. And there is no longer a need to find a pot sitter when you go on vacation.
Drip systems have also become easier to maintain and repair. Filters installed near the valve remove debris that used to clog the small heads. The heads can now be easily disassembled to clean.
One issue remains: “Bugs like to crawl up in the holes,” says Kemper, and that can be a problem when they don’t come out again.