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Question from unknown, Blanding, UT, San Juan County -

We planted 52 new 4-6 ft. trees in March 2016. We have been watering them 3 times a week (about 10 gallons per watering). Now that it has cooled off and turning fall, how often do they need watered?

Answer from Dr. Mike Kuhns, USU Extension Forester and Professor (sent 9/12/16) -

Roots will grow as long as the soil they are in is moist and while the soil temperature is above 40 degrees F. And it is good for roots to keep growing because it will speed the trees' recovery from transplant shock. But once it cools off enough then little water will be transpired from vegetation and it won't take much to keep the soil moist. So as long as it stays cool you can back off to maybe once every couple of weeks, or don't water at all if you get significant precipitation. A good way to tell how deep you are watering if the soil is not too rocky is to use a probe like a long screwdriver or a steel rod welded to a handle to form a tee. It will penetrate moist soil and will stop when it reaches dry soil. You would like to water enough that the soil is moist down to at least a foot.