May 31, 2023
Tree watering rules of thumb
Most trees will not require watering after three years, but during periods of drought, trees will need some help. Below are a few recommendations to help trees survive drought conditions.
• Water trees three times a month in addition to watering your lawn.
• Deep watering to a depth of 12” inches below the soil surface is recommended. Saturate the soil around the tree within the “dripline” (the outer edges of the tree’s branches) to disperse water down toward the roots.
• For evergreens, water 3’-5’ beyond the dripline on all sides of the tree.
• The objective is to water slowly, dispersing the flow of water to get the water deep down to the trees roots. Watering for short periods of time only encourages shallow rooting which can shorten tree longevity. Don’t dig holes in the ground in an effort to water deeply. Digging holes dries out the root system.
• Overhead spraying of tree leaves is inefficient and should be avoided. Watering at ground level to avoid evaporation is the most efficient.
• How much water your tree should receive depends upon the tree size. A general rule of thumb is to use approximately 10 gallons of water per inch of trunk diameter for each watering. Measure trunk diameter at knee height. General formula: Tree Diameter x 5 minutes = Total Watering Time. Example: When you hand water using a hose at medium pressure, it will take approximately 5 minutes to produce 10 gallons of water. If you have a 4” diameter tree, it should receive 40 gallons of
water - multiply by 5 minutes to equal total watering time of 20 minutes.
Information for this article was taken from CSU Extension and is available at http://www.colostate.edu/Dept/CoopExt/4DMG/Trees/caring.htm. For further tree information, please contact the Chouteau County Extension office at 622-3751 or stop in for a visit. We are located in the green building next to the Chouteau County Courthouse.
Montana State University U.S. Department of Agriculture and Montana Counties Cooperating. MSU Extension is an equal opportunity/affirmative action provider of educational outreach.