Plant Pathology Infobytes
February 4, 1999
Blossom-end Rot of Tomatoes - Planning Ahead Pays Off
Dark brown or black blotches on the bottom of tomato fruit is a sure sign of blossom-end rot. This problem shows up in many home vegetable gardens across Mississippi each season, but there are steps which can be taken in late winter which will help prevent blossom-end rot in the next crop.
Before covering control measures for blossom-end rot, let's make sure you know what it looks like, since home gardeners sometimes confuse the problem with other tomato diseases. The first indication of blossom-end rot is a slight discoloration, water-soaked in appearance, occurring at the blossom-end (bottom) of the fruit. This area enlarges rapidly, producing a brown or black sunken area. The skin over the affected area becomes dry and leathery.
Blossom-end rot is caused by a shortage of calcium in developing fruit. This may be due to a lack of calcium uptake from the soil or to extreme fluctuations in water supply. Tomato plants growing in soils low in calcium and soils which are alternately wet and dry during fruit development are more likely to show blossom-end rot. Also, this problem generally is more severe when plants are fertilized too heavily with nitrogen fertilizer.
It's never to early to begin plans for correcting past garden problems, so give the following recommendations a try. They should reduce fruit losses to blossom-end rot:
If you have questions about blossom end-rot, or any other gardening problem, give us a call at your county Extension office.
Infobytes newsletter was written by the late Dr. Frank Killebrew, Extension Specialist.