If you've ever wondered how to properly water your trees, look no further here is your

ULTIMATE TREE WATERING GUIDE

How much and how often to water

Although we may be in a drought, the importance of watering your tree properly will shape our urban forest for years to come. It is important to be diligent about regular watering, especially in the first year. Here are some tips. 

Water your tree 5 gallons every 3 - 4 days, or a total of 10-15 gallons weekly. Because this is only a rule of thumb, it will need to be adjusted to your unique site.  To do this, check the soil moisture a few inches below the soil surface of the rootball.  If the soil is very dry or leaves look wilted you will need to water more frequently.  It should feel moist, but not soggy.  If there is any excess moisture, wait 1-2 days then check the soil moisture again before watering.  Too much water is just as bad as not enough!

How to water

If possible, irrigate in the evening or early morning using low flow rate for a long duration within the water basin (a raised mound of dirt around the tree trunk, forming a circle 18' in diameter around the tree) to ensure that the entire rootball is saturated.  *Note: to determine the duration needed to water 5 gallons, you can time how long it takes to fill a 1 or 5 gallon bucket at a given flow rate. 

General Information

• Turf sprinkler irrigation systems alone do not provide sufficient watering for young trees to survive; additional deep-watering is necessary to saturate the rootball in most cases. 

• Ensure that the watering basin around the trunk of the tree holds water. If water drains out of the basin, the tree's roots are not getting watered.  Keep the soil inside the watering basin free of all vegetation - this includes grass!

• It may be necessary to make adjustments in the frequency and duration of watering depending on soil type, drainage, weather, and trees species. 

• Water your tree IMMEDIATELY after planting…waiting even a few hours makes a difference with tree survival.

• Most established trees will benefit from periodic, but infrequent deep watering, particularly during the dry season. It may be necessary to make adjustments in the frequency and duration of watering depending on soil type, drainage, weather, and tree species.

• Use mulch or woodchips in the watering basin to conserve soil moisture.

Seasonal and Yearly Information

Dry Season and Summer Months: Irrigate trees planted during the dry season 2 to 3 times a week for the first few months and every 3 to 4 days thereafter until the rainy season. It may be necessary to water more frequently during particularly dry, hot weather.

Rainy Season and Winter Months: Irrigate trees planted in the late winter to early spring on a weekly basis, when rain is lacking. Begin deep watering once to twice a week with the approach of warm, dry weather – water thoroughly.

1st Year After Planting

Most young trees need 10-15 gallons of water each week for the first year. We recommend watering 5 gallons every 3 - 4 days. Note: to determine the duration needed to water 5 gallons, you can time how long it takes to fill a 1 or 5 gallon bucket at a given flow rate.:

2nd Year After Planting

Gradually reduce the frequency of watering during the second year to a weekly basis. Begin in late spring and continue through early winter as needed. 

3rd Year After Planting

By the third year, deep watering every other week should suffice, but remember to check your tree often. Watering during the rainy season may not be necessary - remove the soil berm that forms the watering basin - Do not pile soil/mulch up against the tree trunk or change the grade of the soil under the canopy. 

4th & 5th Years After Planting

Many trees will thrive with 2 or 3 deep soakings during the summer of the fourth or fifth year. Most established trees will benefit from periodic, but infrequent deep watering, particularly during the dry season. Monitor your tree carefully!

Caution

Certain mature trees have lower water needs. Avoid plantings in irrigated areas and reduce watering to once per week after the 1st year for the following species:

• CA native Oaks (Quercus spp.)
• Chinese Pistache (Pistachia chinensis)
• Arbutus ‘Marina’ 
• Marina Madrone (Arbutus 'Marina')
• Crape Myrtle (lagestromia x fauriei)

These trees will survive the summer with no further irrigation. Any watering done should be outside the drip line of the canopy.