Posted: 06/05/2017 at 22:03
As recommended by Italophile, a long time poster on here, I only water mature tomato plants when the leaves begin to droop.
Sometimes this means watering only once or twice a week, depending on the weather. the toms are in bucket-sized pots with at least four inches of space at the top. When I water I fill the pot to the brim and leave it to drain.
We have had virtually no blossom end rot since I've followed this watering regime.