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Tree Care Guide

Tips on Tree Watering from the Colorado Tree Coalition

Sometimes your trees could use a drink. Prolonged dry periods and high winds can dry trees and soil. Watering your trees will help ensure their optimum health.

Illustration of tree and roots
The boxed area is the drip line, or critical root zone.

Tree roots are not like carrots

Tree root systems can spread two to four times wider than the height of the tree. Most of the tree's absorbing roots are in the top 12 inches of soil.

Water should be applied within the drip line (the critical root zone shown at left).

Water deeply and slowly

Apply water so it moistens the soil in the critical root zone to a depth of 12 inches. Water with a deep root fork, soaker hose, five-gallon bucket or soft spray wand. Apply water to many locations under the drip line. If you use a deep root fork or needle, insert the device no deeper than eight inches into the soil.

How much water to apply

April through September: In normal precipitation years, trees located in irrigated turf areas do not need additional water.

When watering restrictions prohibit turf watering, or when trees are not in turf areas, water small trees four times per month, medium trees three times per month and large trees two times per month.

October through April: During prolonged dry periods, water once or twice a month, using 10 gallons of water for each inch of the tree’s diameter. Water only when the temperature is above 40 degrees and there is no snow on the ground.

Mulch helps retain soil moisture

Mulch helps conserve soil moisture. Apply organic mulch within the drip line, at a depth of three to four inches. It is best to eliminate turf prior to adding mulch. Leave a six-inch space between the mulch and the tree trunk. Mulch materials may include wood chips, bark, leaves and evergreen needles.

Moisture is needed to avoid disease

Maintaining consistent soil moisture allows for better water absorption. Stressed trees are more vulnerable to disease, insect infestations and branch dieback.

The Colorado Tree Coalition has more advice about tree health from professional foresters, arborists and water conservation specialists.

Summer tree watering schedule (April – September)

April – September Tree Watering Schedule
(Minimum Water Requirements)
  Small trees Medium Trees Large Trees
  Weekly
(10 gallons/inch)
Three times a month
(10 gallons/inch)
Two times a month
(15 gallons/inch
)
Trunk size in
diameter (inches)
1" 2" 3" 4" 6" 8" 10" 12" 14"
Watering Device  
Deep root needle

 

5
min
10
min
15
min
20
min
30
min
40
min
75
min
90
min

105
min 

soft spray wand

 

3
min
5
min
8
min
10
min
15
min
20
min
38
min
45
min

53
min 

soaker hose

 

5
min
10
min
15
min
20
min
30
min
40
min
75
min
90
min

105
min 

 

Winter tree watering (October – March)

October – March Tree Watering Schedule*
(Minimum Water Requirements)
  Small trees Medium Trees Large Trees
  Weekly
(10 gallons/inch)
Three times a month
(10 gallons/inch)
Two times a month
(15 gallons/inch
)
Trunk size in
diameter (inches)
1" 2" 3" 4" 6" 8" 10" 12" 14"
Watering Device  
Deep root needle

 

5
min
10
min
15
min
20
min
30
min
40
min
50
min
60
min

70
min 

soft spray wand

 

3
min
5
min
8
min
10
min
15
min
20
min
25
min
30
min

35
min 

soaker hose

 

5
min
10
min
15
min
20
min
30
min
40
min
50
min
60
min

70
min 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

* Water only when the temperature is above 40 degrees and there is no snow on the ground.