Tomato blosom end rot

Tomato blossom end rot has been happening
a lot this year.  It happens a LOT almost every
year in some form.  This is a physiological
characteristic of when the weather is too hot,
 too cold, too wet or too dry and the ability of
the tomato to absorb calcium is limited.  The bottom
end of the tomato plant then turns leathery and
brown-tannish. 

http://pnwhandbooks.org/plantdisease/tomato-
lycopersicon-esculentum-blossom-end-rot

Solutions:  Add ground up oyster shells, or add
any kind of lime. Preferably in October before
the winter rains but can be applied anytime.

Mulching helps to avoid the water hi low swings. 
Temp swings, no solutions.