Irrigating Fruit Trees in the Winter Depends

Q.  How often do deciduous fruit trees, in this case a Blenheim apricot, need to be watered during the dormant season?

A. It's hard to give a blanket recommendation about how often to water because of the differences in soil, root growth and if people are using a surface mulch or not. Because of these differences, how often to irrigate might vary a couple of days either way.

            The best way is to use a moisture sensor such as those inexpensive houseplant moisture sensors. Insert the tip in the soil about 6 inches deep and irrigate when the meter is around 6. You should be at able to water no sooner than every 7 days and maybe every 10 days depending upon your conditions.

Soil moisture sensor with 24 inch stem

            But if the tree is surrounded by dry soil it may be closer to 7 days. If the tree is surrounded by other trees that are irrigated, it might be 10 days. And if you have the soil covered in 3 or 4 inches of woodchips you can extend it perhaps an extra 2 days. That's my best guess.

            But you are better off using a moisture sensor to get it more accurate than this. To determine the number of minutes to irrigate, I use a long probe like three-eighths inch rebar and push it into the soil after an irrigation. It's hard to push it deeper if the soil is dry beneath where you water. Recently at one of my classes, someone mentioned they are using a wooden dowel to do the same thing.

Soil moisture sensor meter reading "0" or dry.

            I just push it down until it's hard to push any further and that tells me how deeply I've irrigated. With fruit trees I like to irrigate 12 to 18 inches deep.