>My experience is that drought is the main cause of blossom end rot on
>tomatoes. In my experience roma varieties suffer most from this during
>drought, possibly due to the shape.
>With no water coming into the carrying nutrients, the plant steals what
>it needs from the fruit. A blister occurs in the fruit and the rot
>develops from there.
We are hearing that blossom end rot is caused by a lack of calcium
combined with improper watering practices and variety.