Tree Watering Guidelines
Watering your tree gradually and deeply will ensure that your tree thrives. Apply water slowly and evenly to the tree’s root zone, saturating the soil to a depth of 12-18 inches. Use the guidelines below to help determine the specific watering needs of your tree.
|Three days after planted||Fill the watering basin 3 times, using a total of 15-20 gallons||15-20 gallons||Hand watering best at this stage|
|First three weeks after planting||Fill the watering basin once a week||5-10 gallons||Depends on flow rate|
|Two – Six months following planting||Fill the watering basin every week or every other week||10-15 gallons||Depends on flow rate|
|Remainder of first year||Water every other week in absence of soaking rain||10-15 gallons||Depends on flow rate|
|Year Two||Every two to four weeks when rain is scarce||15-20 gallons||Depends on flow rate|
|Year Three-Five||Once a month||20-30 gallons||Depends on flow rate|
Check whether your tree species has low, moderate, or high water needs on Canopy’s tree library.
|Dry California Native Oaks||DO NOT IRRIGATE MATURE NATIVE OAKS
See: Caring for Mature Native Oaks
|Low water needs species||Once or twice
in the dry season
|10-15 gallons/inch of trunk diameter||Approx. 90 minutes||Approx. 45 minutes|
|Moderate water needs species||Every other month||10-15 gallons/inch of trunk diameter||Approx. 90 minutes||Approx. 45 minutes|
|High water needs species (Thirsty trees)||Monthly||10-15 gallons/inch of trunk diameter||Approx. 90 minutes||Approx. 45 minutes|
May to October generally has almost no rainfall. If spring or fall is unusually wet or dry, irrigate accordingly.
Hand-watering: A good choice for establishing young drought-tolerant trees. Create a soil basin within the drip line, fill with water from a hose or bucket, and allow to soak in. See Caring for Young Trees for further instructions on basin watering.
Drip irrigation: To use water most efficiently, install a drip irrigation system or convert your sprinkler system from spray to drip. With these methods, water is applied at a slow rate directly where it’s needed near the tree roots. Soaker hoses can be a cost-efficient alternative.
- When possible, give your trees their own dedicated irrigation valve, since trees require deeper watering than ground covers or shrubs. For a new system, tap into an existing hose bib. Consult with your irrigation contractor, or bring a layout diagram of your property to your local hardware store or irrigation supply house to get advice.
Watering methods to avoid:
Lawn irrigation: Does not water trees successfully. It generally reaches only the first few inches of soil, encouraging trees to form weak “surface roots.”
Sprinklers and spray irrigation: These methods apply water at a fast rate, resulting in water loss due to runoff and evaporation. If you have an existing sprinkler system, however, there are ways to make it more water efficient:
- Replace nozzles with water-efficient models. These apply water more slowly, which gives water more time to soak into the ground and reduces runoff.
- Break water run cycles into smaller periods in the same day—this allows more water to penetrate the soil. For example, use two 20-minute periods separated by a brief rest (to allow water to soak in), rather than one 40-minute period. Most irrigation controllers can be adapted to do two start times automatically.
- Apply only 1 inch of mulch so water can penetrate easily.
- As your tree grows, move nozzles farther out from the trunk, and consider removing additional lawn.
- Adjust watering frequency and duration. Water thoroughly, but less frequently, allowing the soil to dry out between waterings.
- Inspect your irrigation system every spring to look for leaks or clogged spray heads or drippers. Move drippers away from the tree as it matures, always apply water at or near the drip line of the tree and slightly beyond.
- This chart assumes drippers are placed approximately 3’ apart, with an application rate of 1 gallon per hour (GPH).
- Soaker hoses have variable output. Check depth of watering and adjust time as necessary to water tree to a depth of 18 – 24” for most mature trees.
- Top mulch should be applied over drippers to a depth of 3 – 5”
- Higher flow bubblers are recommended for newly planted trees to achieve even coverage. Install 1-gallon-per-minute (GPM) emitters. Maintain a solid watering basin that can hold 10 to 15 gallons. If necessary, split run time so water does not overflow the basin.
- Drip and soaker hoses are always preferred over spray irrigation because they are more water efficient (less water loss to run-off or evaporation).
- If you are using spray irrigation, use only 1″ of top mulch so that water can still penetrate.
- 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. This will reduce run-off and give the water time to soak into the soil between applications.
- 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.