Watering 101

Did you know that overwatering is the most common problem in home and commercial landscaping? Or that outdoor watering can cause water use to double or triple during the summer? This is often 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 system — is a key component to your water conservation efforts. The first point to remember is that the greatest waste of water is watering too much, too often. Below are some basic tips to get you started.

Water When Temperatures Are Cooler and the Air is Calmer
Make sure you water before 10 a.m. or after 6 p.m. when temperatures are cooler and the afternoon winds have calmed so that evaporation is kept to a minimum.

Apply the Amount of Water Your Soil Can Absorb
The amount you water should be based on soil conditions and plant needs. Here in the Pacific Northwest, soils are typically clay or sandy loam, which may take longer for the water to penetrate. 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 watering so that you apply water for a shorter time period, let it soak in, and then repeat the process. For example, if your watering schedule is 40 minutes per week and you plan to water 2 days per week, your new “cycle and soak” schedule might be to water for 10 minutes at 6 a.m. and then again for 10 minutes at 8 a.m.

Water to Your Plants’ 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 about your plants’ specific watering needs.

Amend Your Soil with Mulch
Mulches come in two forms — organic and inorganic. Organic mulches include aged manure, kitchen compost, and bark chips or wood chips. Organic mulches increase the soil’s ability to store water by covering and cooling the soil thereby minimizing evaporation. Inorganic mulches, such as gravel and river rock, can provide interesting landscape textures; however they do absorb and re-radiate the sun’s heat, increasing the amount of water surrounding plants will need to survive. Mulches also reduce erosion and help with weed control.

Use about 3 inches of organic mulch for weed control, but do not bury the crowns of plants because they may smother and rot. If the mulch is too deep, water will have a difficult time reaching the plant roots.

Group Plants with Similar Water Needs
Different plants need different amounts of water, sun, and shade to survive. Some microclimates of your yard are probably hotter and drier, or wetter and cooler, than others.

Create Watering Zones In addition to your yard’s microclimates, look at creating watering zones within your landscape. Inside each zone, all of the plants should have the same general watering needs, allowing you to give each plant the water it requires — not too much or too little. Watering zones help you avoid wasting water while helping to reduce the time and effort needed to maintain your garden.

Set It, but Don’t Forget It
The key to efficient irrigation is to adjust watering schedules frequently during the season. If you set your automatic controller once for the hottest part of the summer and let it run all season, you’re wasting a lot of water that could damage your plants along with your wallet. Most modern controllers allow you to easily adjust your watering schedule based on the weather.

Water Thoroughly, but Infrequently
Watering thoroughly, but infrequently, will help roots go deeper, resulting in more water efficient, drought-tolerant plants. This is one reason the City recommends watering one or two times per week. It will also save you time.