Outdoor watering can be quite costly. Adjusting your sprinkler controller to water just the amount your plants need can be challenging. Learn how to generate watering schedules for automatic irrigation systems. Visit the Saving Water website where you will find an easy to use calculator designed to provide schedules for basic landscape water requirements in the Seattle metropolitan area.
When to Water
Water early in the morning, between 4 and 10 am. Doing so allows the plant foliage to dry, making it less susceptible to foliar diseases. Early morning watering also ensures less distortion of sprinkler patterns and reduces evaporation due to lower winds and cooler temperatures.
Create water zones by putting plants together that have similar water needs. Doing so minimizes the potential of over watering and under watering neighboring plants. Where woody plants must be included in turf grass areas, consider using water-loving or water-tolerant plants, which can remain healthy under relatively high amounts of irrigation. Irrigation for established woody landscape plants should be focused at and/or beyond the drip line to promote extensive rooting, and should be applied deeply into the soil (water delivered deeper than the 2- to 3-foot range, however, will not be accessible by most of the plant roots).
In new landscapes with automatic irrigation systems, newly installed plants may not receive the thorough watering required to promote early vigorous root establishment; supplemental hand watering, therefore, may be needed to provide the watering necessary (this is especially true for small plants which may dry out quickly or large plants with deep root balls).
Rebates are available for some sprinkler system upgrades. Find out all the details of the rebate program and lots of other tips regarding outdoor watering at the Saving Water website.
Saving Water with Soaker Hoses
Soaker hoses are a great way to save water and keep plants healthy. They slowly leak water directly into the soil, instead of spraying it into the air and wasting water through evaporation. Plus, they put the water in the root zone - right where your plants need it - not on plant leaves where moisture can cause rust and other diseases. Check out the fact sheet for information on buying soaker hoses and installation tips (PDF).
In addition to estimating the amount of required irrigation water, it’s important to also consider the type of soil and the amount of slope that is found in the landscape. Soil type and slope have a significant effect on the amount of water that can be stored in the soil and how quickly the water can be absorbed. In general, sandy soils quickly absorb water but hold the least amount of water; clay soils hold the most soil moisture but absorb water at a slow rate.
If you need help in determining the soil texture of your landscape, contact your local Extension Office for information on performing a basic soil test. You can reach Washington State University King County Extension office by calling 206-205-3100. They will send you a packet of information that tells you how to take your soil sample, approximately how much it will cost and where to send the sample