Watering Efficiently

The greatest waste of water is watering too much, too often. Here in the Portland metro area, our water consumption is at its highest during the summer months – often doubling or tripling - due to outdoor watering.

Oftentimes this is because people don’t know how much water their landscape needs. And, it’s one reason why irrigation — whether it’s a single sprinkler attached to a hose or a sophisticated underground irrigation system — is a key component to your water conservation efforts.

Below are some basic watering tips to get you started.

What time of day should I water my garden or landscape?

You should water your garden or landscape before 10 a.m. or after 6 p.m. when temperatures are cooler and the air is calmer so that evaporation is kept to a minimum.

How often should I water my garden or landscape?

We recommend watering established landscapes twice a week. Watering thoroughly, but infrequently, will help roots go deeper, resulting in more water–efficient, drought–tolerant plants. Newer plantings, vegetables, and potted plants may need more frequent watering.

How much should I water my garden or landscape?

The amount you water your garden or landscape should be based on your garden’s soil conditions and your plant’s water needs. On average, we recommend watering your lawn about an inch a week – a bit more during long, hot, dry spells and a bit less during the cooler spring and fall.  Trees, shrubs, and perennials typically don’t need water as frequently, however they may require more volume at each cycle, so it is best to check with your local garden center or landscape professional on your plant’s specific water needs. 

Be sure to adjust the amount you water throughout the summer

The key to efficient irrigation is to adjust the amount you water frequently during the irrigation season - watering more when it is hot and dry, less when it is cooler and wet. While it may be more work to adjust the amount you water your landscape throughout the summer, the extra effort will help you use water more efficiently in your landscape. And, most automatic irrigation systems have controllers that allow you to easily adjust your watering schedule. We recommend using the Consortium’s Weekly Watering Number as a guideline for how much to water your garden or landscape throughout the irrigation season.

What do I do if run off or puddling occurs while watering my garden or landscape?

Here in the Pacific Northwest, soils are typically clay or sandy loam which means that it may take longer for water to penetrate into them. If this is the case with your garden or landscape’s soil, then you may have to adjust your watering schedule so that you are only applying the amount of water that your soil can absorb each time that you water. Run off and puddling are visible cues that water is being applied at a quicker rate than it can be absorbed.

If this occurs, you may want to use a “cycle and soak” pattern for your watering. To do this, apply water in several shorter sessions each day that you water. This will allow the water to soak gradually into the soil in between the watering sessions. For example, if your watering schedule is 40 minutes per week and you plan to water two days per week, your new “cycle & soak” schedule might be to water for 10 minutes at 6 a.m. and then again for 10 minutes at 8 a.m. on both of your watering days.

Looking for more detailed information?