Tree Watering Guidelines

How should trees be watered in this region?

We should infrequently yet deeply water our trees in the most efficient manner possible.

Consider 4 factors when watering your trees:

  • Method of water application (e.g. sprinklers, drip systems)
  • Duration of application (how much water and for how long?)
  • Frequency of application (how often?)
  • Location of application (where to water?)
  • Additionally, conserve water by using top mulch to preserve moisture

These factors vary based on the age, species, and environment of the tree. We’ve outlined watering requirements based on the following five categories:

  • Established native California oaks
  • Mature trees with low water requirements
  • Mature trees with moderate water requirements
  • Mature trees with high water requirements
  • Newly planted trees – see also Caring for Young Trees

Check your trees’ watering requirements in the Canopy Tree Library.

Irrigation During Dry Summer Months (May – Oct):

                                                     Irrigation Method
Tree Type Frequency Drip
Run time
Run time
Run time
See: Caring for Mature Native Oaks
Low water needs Once a month 90 minutes 45 minutes  
Moderate water needs or young trees Twice a month 90 minutes 45 minutes  
High water needs (Thirsty trees) Weekly 90 minutes 45 minutes  
Newly planted trees Twice weekly
or weekly
30 minutes
2 emitters
per tree
45 minutes

90 minutes

May to October generally has almost no rainfall. If spring or fall is unusually wet or dry, irrigate accordingly.

Notes on Drip Application:

  • This chart assumes drippers are placed approximately 3’ apart with 1 gallon per hour (GPH) application rate.
  • Soaker hoses have variable output. Check depth of watering and adjust time as necessary to water tree to a depth of 18 – 24”.
  • Top mulch should be applied over drippers to a depth of 4 – 6”

Notes on Sprinkler and Bubbler Application:

  • Drip and soaker hoses are always preferred over spray.
  • Top mulch depth should be reduced to 1” for spray irrigation.
  • If using conventional spray nozzles, split sprinkler irrigation into two times separated by one hour: for example, two 20-minute applications equal one 40-minute application.
  • Conventional spray heads apply approximately 2.0 inches of water per hour.
  • Replace nozzles with water-efficient nozzles, which will save water and reduce runoff. One start time is adequate with this method.
  • Bubbler application rate is assumed to be 6 – 8 gallons per hour (GPH). Either build a berm to hold 10-15 gallons, or split run time so that water does not overflow the basin.