Trees offer several environmental and community benefits. Losing a tree to the drought or other causes can be like losing an investment, as it takes many years for trees to reach a maturity level where we can capture those benefits. The information below will guide you on how to water your trees effectively during the drought and save water.
Watering your trees is not always an exact science. We recommend you run a test to ensure that water is soaking in deep enough to reach your tree’s feeder roots. To be sure you are watering long enough, follow the steps below. You can also track how many gallons of water this will require by checking your meter. See below for details:
1. Check your meter before running your irrigation so that you can measure how many gallons you will need. Record the number on the meter. For your measurement to be accurate, make sure no other water is running in your household.
2. Turn on your irrigation for 30 minutes. Make sure you are using either a soaker hose or inline drip to water the area around your tree’s drip line. See the diagram to the right to find this area.
3. After 30 minutes, use a soil probe or dig down to test the soil. For a mature tree, the water must reach 18 inches deep. Based on how deep the water reached after 30 minutes, you can estimate the time required for you to effectively water your tree.
Example: If you test the soil and find it is dry deeper than 6 inches, then you know that your tree is only getting one-third its water requirement. Based on this, you will need to water your tree for 90 minutes total. This can be done all at once or over a few days.
4. Check your meter after running the irrigation for 30 minutes and record the new number. Subtract the first number you recorded from this new number to get the difference. Your meter measures water in cubic feet. One cubic foot is equal to 7.48 gallons of water, so multiply the difference by 7.48 to determine how many gallons of water were used in 30 minutes.
Example: If the difference that you calculate is 50 cubic feet, simply multiply 50 by 7.48 to get the number of gallons used (50 x 7.48 = 374). If you need to water for 90 minutes total, then this will require 374 x 3 = 1,122 gallons of water total, or 1.5 HCF billing units (1 HCF = 748 gallons).
Trees can show signs of stress for several reasons. If you have questions about your tree, contact an arborist.