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Summer Watering - Healthy Trees and Healthy Lawns

automatic sprinklersAre you using the same sprinklers for your trees and your lawn? Relying on the same type of system for both will lead to shallow tree roots and a weaker tree, less capable of withstanding heat and droughts.

Typical home sprinkler systems waste up to 50% of water due to one or more of the following:

  • Watering during the day. Evaporation from wind and heat can account for a 20-30% water loss. That’s why there is a City ordinance that prohibits watering between 9:00 am and 5:00 pm. Two to three hours before sunrise is the optimal time to start irrigating.
  • Non-managed automatic sprinkler systems. Even “automatic” systems need management! When timers are set for the hottest part of the year and are not adjusted seasonally, water is wasted. Similarly, this can happen if the system is not manually overridden when it rains. State law requires sprinklers to be off during and 48 hours after it rains. Adding a weather-based irrigation controller solves these problems. These controllers irrigate based on weather conditions, soil type, sun exposure, and plant types. Check your eligibility for a rebate at
  • Leaks and overspray. Both are violations of the City water ordinance as well as substantial wastes of water. Systems should be checked several times a year to see if a sprinkler is spraying onto the driveway, sidewalk, or area that doesn’t need watering. Let it run through a full cycle to check for significant water runoff.
  • Old style sprinkler heads. The newer rotating nozzle replacements can reduce water usage up to 30% and are eligible for rebates.


Tips for Lawn Watering

  • If the grass springs back when you step on it, the lawn doesn’t need water.
  • Let the grass grow longer to promote deeper root growth. This results in a more drought-resistant lawn, reduced evaporation, and fewer weeds.
  • Check the soil with a moisture meter. They are inexpensive and available at most garden and home improvement centers.

Tree Care

Trees are a critical part of our landscape. Because they have much deeper roots than grass, they should be watered differently. Now’s the time to get trees ready for summer, before it gets hot and trees become thirsty.

Here are tips for watering trees the right way:

  • Set up drip irrigation or a soaker hose to give trees a slow, deep drink. Extend drip and soaker hoses to the edges of the tree canopy (rather than watering near the trunk).
  • Check the soil moisture at different points under the canopy. If it’s dry, soak the soil 12 to 18 inches deep, watching for runoff. Water young trees at least twice a week and three times a week during heat waves.  Water mature trees when the soil dries out six inches below the surface (usually once per month). 
  • Layer mulch around your trees. Mulch helps moderate soil temperature, reduces evaporation, and controls weed growth. As it breaks down, mulch also adds valuable nutrients to the soil. Spread the mulch like a donut around the tree, keeping it four inches away from the trunk, layering it up to six inches deep and spreading it in a three to four-foot diameter around the tree .

By following these guidelines, most people will see a dramatic reduction in water usage and have healthier lawns and trees.

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