The goal is moist soil as far as 8 to 12 inches
below the surface.
- For the first three years, young trees
need weekly watering from mid-April to
- Probe your soil 8 to 12 inches below the
surface before watering. If the soil feels moist
and sticky, allow it to dry for several more
days before watering. If the soil feels dry and
crumbly, water deeply once a week.
- Water deeply by setting your hose on a slow
trickle for several hours at the base of the
tree or use a soaker hose around the tree. On
average, your tree will need 15 gallons of water
- Remember that lawn watering will not replace
the need to deeply water young trees.
Additional Watering Tips
# 15 tree (15 gallon tree) needs about 15 gallons of water 1 time a week
during he dry months and twice a week when the weather is above 100
- A #5 tree (5 gallon tree) needs about 10
gallons of water 1 time a week during the dry months and twice a week
when the weather is above 100 degrees.
An excellent way to determine how well your soil drains is to dig an 18
inch hole about a foot deep (width is not a factor). Fill the hole with
water and let it drain out all day and overnight. Fill to the top the
next day. Place a stick in the center of the hole and mark the water
level on the stick. After 30 minutes and then again, each hour, measure
the water level. Poorly drained soil will drain about one-half inch per
hour. Moderately draining soil will drain ½ to 1 inch per hour. In soil
that is well drained, water will recede 1 inch or more per hour.
The dripline is at the edge of the canopy.
Roots extend beyond the dripline.
Deep water your trees to allow all the roots to absorb moisture.
- The best way to deep water trees is to use a soaker hose (or a garden hose set to a trickle) that slowly applies water to the soil over several hours. Sprinklers may be used to water deeply by watering until water begins to run off, then waiting at least an hour or two to resume watering. This should be repeated until water has penetrated at least one foot in depth.
- Special care needs to be taken when watering on a slope. Water around and beyond the dripline of mature trees where the roots are, not near the base of the trunk.
- Watering during our rainless months varies greatly depending on the tree species, daily temperatures, and location in the yard, as well as soil texture, structure and depth. Click here for a table of water needs for mature trees.
- Use a shovel or soil sampling tube to check the depth of moisture to at least a foot.
- Established drought tolerant trees may need occasional watering at one or two month intervals. California native oaks, California laurel, cork oak, Chinese pistache and goldenrain trees can be damaged and short lived with frequent summer watering.
- Moisture adapted trees such as birches, redwoods, magnolias and red maples may need regular deep watering throughout their lives to look their best and perform well. These and other species greatly benefit from an occasional deep watering to the depth of at least a foot once or twice a month.
- Trees in or near lawn areas with frequent shallow watering may develop surface roots.
- Poorly adapted Monterey pine, Leyland cypress and giant sequoia are prone to insect damage and diseases in hot dry interior areas of the state regardless of how much water they are given.