Q: I have a sick orange tree. One side is doing somewhat well, but the other side is dying, and the leaves are curled up. There is no sign of insect infestation. I have to water the tree every four to five days, otherwise the leaves begin to shrivel. I think the tree is about 6 years old but could be more. Originally it was on a drip system, but I stopped that about a year ago and use a sprinkler spray.
A:Β The tree is old enough to be established in its current location. The sprinkler you are using is likely not delivering enough water and not deep enough. I recommend you adjust your irrigation schedule to deliver enough water to reach a depth of 36 inches at the drip line once every two weeks. You can still use the sprinkler but it will not be as efficient as a drip system. More is lost to evaporation when it is airborne. You can check the depth the water is reaching by using a soil probe. The simplest kind is a three-foot piece of rebar with a handle that you can push into the ground after irrigation. It will meet resistance when you hit dry soil.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed toΒ tucsongardensage@gmail.com
