How to Water A Tree

Start with these two short videos about how to water mature trees and water young trees . Also in Spanish .

Where do you water a tree?

Roots often extend far beyond the edge of the canopy, or drip line. Water under and just beyond the drip line.
Most absorbing tree roots are in the upper 18 to 24 inches of the soil. Water only needs to reach that deep.

Use drip irrigation or micro-spray, and set up separate irrigation zones for trees
When lawns are removed, trees still need to be watered and tree roots need to be trained to grow deeper. In the first year, gradually increase the duration and decrease the frequency of watering the trees
Save water by planting trees in the fall and winter when rains and cooler weather reduce the watering needs.

Trees can be stressed, become more susceptible to pests, decline, and die if they aren’t watered.
Trees are expensive to replant, water, and maintain, and they take many years to mature.
Removing dead trees often requires professional help, which can cost $1000 or more per tree.
Trees shade other landscaping and reduce their water needs.
When lawns are removed, trees still need to be watered and tree roots need to be trained to grow deeper. In the first year, gradually increase the duration and decrease the frequency of watering the trees.
Look at the trees—how are they doing?’ Are other trees putting on new growth and yours are not? Are your trees dropping a lot of leaves (if they are deciduous) when others are not? Has your tree failed to leaf out in the spring? Are the leaves wilting or turning brown? Or are the leaves a dull color, when others are a shiny green? Then the tree is probably not getting enough water.

Trees need water in the rainy season (winter) if rainfall is below normal or if weather is extremely hot or windy.
When Santa Ana winds are predicted, water trees deeply in the early morning. Water 1-2 days before, daily during the wind event, and the day after winds subside.
Trees need extra water in the rainy season (winter) if rainfall is below normal. Some trees are now dying if they didn’t get supplemental water in the past four winters.
After each winter storm, check the soil 12” below the ground—and if the soil is dry, then water the tree until the soil and roots are moist at that level.
Even the strictest drought restrictions allow for watering trees on residential and commercial properties, and landscape vegetation in parks, schools, and other public places. Use drip irrigation, and set up separate irrigation zones for trees.

Use greywater or rain barrels
Use soaker hoses for a few months, until irrigation zones set up
Check soil moisture 12” deep with a moisture meter or feel the soil at the end of a long screwdriver or coat-hanger wire.
Look up water requirements for different trees in the Water Use Classification of Landscape Species (WUCOLS)