|If blossom end rot is due to lack of calcium how can I add calcium to my container grown tomatoes? I fear I may be over watering.|
|You'll probably find that most references to calcium deficiency in tomatoes refer to "blossom end rot". Rather than being caused by a disease, this symptom is caused by poor water relations. For example, if a dry spell is followed by a heavy rain, blossom end rot is a likely result. Gardeners try to keep soil moisture as even as possible--a thick layer of mulch sometimes does the trick.
The actual mechanism for blossom end rot involves calcium--check out this web site for more information and details of how calcium affects water relations in tomatoes.
I hope this is helpful.