Q:Β We have a large ruby red grapefruit tree that is about 12 years old. We have always had nice crops of pink grapefruit until last year. Last yearβs crop had smaller fruits and the flesh was yellow instead of pink. This year, the fruits look like they will be even smaller. We have consistently fertilized the tree three times a year, and it is on drip irrigation. The foliage is nice and dark green. What are we doing wrong?
A:Β Smaller fruit is often a symptom of insufficient irrigation. You said the tree is on a drip system but not how much water it is receiving. The recommendation for citrus trees is a deep soak to a depth of 36 inches every 7 to 10 days in the summer, every 10 to 14 days in the fall and spring, and 14 to 21 days in the winter. If you are already irrigating in this way, please let me know so we can puzzle it out further.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Email questions to tucsongardensage@gmail.com
