Marianne Ophardt

Garden Tips: Conserve irrigation water by not wasting it

It is estimated that more than 50 percent of the water used by an average household is used for irrigating our lawns, landscape and garden. Luckily for us, we have enough water for irrigation this year. It looked like we might have to tighten our belts in regards to watering when the snowpack was below normal in early winter. Fortunately, late winter snows in the Cascades saved us, but climatologists predict that our good fortune is not likely to last.

It is time to start learning and practicing water conservation so we will be prepared for water shortages looming in the future. One way to conserve water is simply not to waste it. How often do you see irrigation water running down the street?

There are easy ways to avoid this:

-- Slow down. Often water is being applied faster than it can sink into the soil, especially on sloped areas. A simple solution is to apply the water more slowly in several short runs with a short break in between until a total of 1 to 1.5 inches of water is applied. This gives the water a chance to percolate into the soil instead of running off.

-- Water only when needed. Often, residents rely on timers to turn water on and off based on a set schedule, never adjusting for weather or checking soil moisture to see if the lawn or plants actually need water. This "set it and forget it" practice is easy but wasteful. Plus, it does not encourage deep root systems or healthy plants.

Dr. Troy Peters, Washington State University Extension irrigation specialist, notes that your lawn and garden do not need the same amount of water in the spring and fall as they do in the hot part of the summer. For example, he says lawns in Yakima "only use about .25 inch of water per week in April and October, 1.25 inches per week in May and September, 1.6 inches per week in June and August, and a little over 2 inches per week in July."

If you leave your controller programmed on a setting of 15 minutes each day for the entire season, you are likely using too much water in the spring and fall and too little in the middle of summer. Peters recommends resetting the timer at least once a month to adjust for the changing irrigation needs.

If your soil is a silt-loam, Peters also recommends putting all the water needed during the week in one weekly irrigation, not a little bit each day. Peters points out that "soil can only hold so much water." When you put on more water than the soil can hold, the excess water is wasted. During the summer, when more than an inch of water per week is needed, Peters suggests splitting the total and applying half of the water with two separate runs per week if the soil is a silt loam. However, on sandy soils, you will have to irrigate more often, but should try not to irrigate every day if possible.

There are other ways to conserve lawn and garden irrigation water, but trying not to waste it is a good start.

-- Marianne C. Ophardt is a horticulturist for Washington State University Benton County Extension.