Rain actually does "go away" on warm, summer days in the Pacific Northwest. During this dry time, when vegetables and flowers bask in sunlight, water use and costs can increase substantially.
Homeowners can learn to save water and money, however, with help from WaterWise Oregon Gardening, a statewide program of Oregon State University Extension. Online information on how to design and plant water-efficient gardens is available at: http://extension.oregonstate.edu/watershed/waterwise-gardening.
The following tips, compiled by Linda McMahan, horticulturist with the OSU Extension Service, can help conserve water and save on summer water bills as well.
* When you're considering new plants, take a look at common WaterWise plants such as black-eyed Susan, sunflowers, blanket flower, California poppy and coneflower. Once established, these plants require minimal irrigation. Group WaterWise plants together for maximum water savings.
* If you like colorful bedding annuals such as zinnias, marigolds, impatiens and petunias, consider putting them in pots or hanging baskets where you can provide water directly, rather than watering the entire garden.
* Hand-water if possible. Research shows that hand-watering can be the most efficient way to irrigate because you often can see when the soil is moist and provide water only when the plants need it. "Turn off the automatic sprinkler this summer and enjoy the outdoors in a new way," McMahan suggested.
* Weeds won't be watered if you fill a milk-type jug and put it upside down beside a plant, burying the spout in the soil. Or bury a coffee can, used gallon pot or milk jug right beside the plant after poking drainage holes in the bottom or sides. Fill the container with water and let it drain out slowly.
* Soaker hoses are an alternative. Hook them to an automatic timer of some kind so you don't forget to turn off the water. This works for both vegetable and ornamental gardens. Drip irrigation is another possibility and works particularly well for shrubs.
* Let your lawn go dormant for the summer. It will "green up" when winter rains begin.
"If you don't want to let your lawn go totally dormant, water less often but deeper," McMahan said. "Daily watering with an automatic watering system promotes shallow roots, while less frequent deeper watering, such as once a week, once every two weeks or even monthly, promotes deeper roots."
* If you water gardens with overhead sprinklers, make sure to measure the amount and supply no more than one inch at a time (measure with a wide-mouth plastic or metal container with a one-inch mark on the side.) Note that overhead watering is not recommended for vegetable gardens because it increases the risk of disease.
* Provide water only when needed. You can look for clues to water stress, such as slight wilting or a dull, transparent look of the leaves. This strategy works well for trees and shrubs.
* When you plant new shrubs and trees, provide a long soak from a hose to saturate the soil deeply in the immediate area. You should repeat this process several times, especially during dry periods, to give your new shrubs and trees the resources to grow strong and deep root systems that will require less water in the future.