US (MS): Common problems with tomatoes
This Mississippi State University Extension publication discusses some of the most common problems, methods of prevention, and sources of more information.
Blossom-End Rot
BER is probably the most common problem in tomatoes (home garden, field, and greenhouse). It appears as a dry, leathery (not mushy), dark brown or black area, usually at or near the bottom of the fruit. BER can sometimes occur on the side of fruit, and occasionally only on the inside of fruit, so the BER is hidden until the tomato is sliced open. Sometimes the spot is sunken, and these tomatoes often ripen before all others.
BER is not caused by an infectious agent (pathogen) and is therefore not a disease. It is a physiological disorder caused by lack of adequate calcium in developing fruit. Most Mississippi soils have enough calcium for tomato fruits to develop properly, but it is a good idea to have the soil tested to make sure.
It’s common to see BER on the first tomatoes of the season. While low calcium in fruit is the cause, the real culprit is often drought. Without a steady supply of water, the tiny root hairs dry out, which limits the amount of calcium the plants can absorb and supply to developing fruit. So don’t let plants wilt between waterings. The best way to reduce the chance of wilting is to mulch around plants.
BER can be especially problematic to tomatoes grown in containers because they have a tendency to dry out more easily. Be sure to provide mulch around the tomatoes to protect the roots. Some varieties are more susceptible to BER than others. If the problem continues, try planting a different variety the following season.
Read more at MSU Extension
