Question: I am growing tomatoes in the backyard, using organic fertilizer every two weeks, and I am getting black spots on the bottom of the tomatoes. What is it and can I control it?
Answer:Β Your tomatoes have blossom end rot. Blossom end rot shows up as a dark, sunken, leathery spot on the bottom or blossom end of the tomato fruit. This often happens in late spring and early summer following a heavy fruit set, a sustained dry period and/or if your fertilizer lacks sufficient calcium. To avoid blossom end rot, the fruit should be thinned, adequate irrigation provided, and a fertilizer with calcium should be used. Calcium, as well as other nutrients, moves slowly in water stressed plants so itβs possible that irrigation alone can solve this problem if you are already providing adequate calcium in your fertilizer.
Peter L. Warren is the Forest Health Program Coordinator for the Arizona Department of Forestry and Fire Management. Questions, photos and videos may be emailed toΒ tucsongardensage@gmail.com.
