What is happening to my tomato's?
I have several tomato plants (early Girl started from seed) as they are starting to ripen the majority have a round 'rotten' spot on the bottom. Picture attached. when i cut into the bad area i do not find any bugs or worms etc. I have harvested 2 that are fine and maybe 10 with the problem. I have the plants in Topsy Turvey (1) and pots (4). Only one plant in a pot in a different part of the yard does not have the problem but that plant does not have any plants starting to ripen yet.
I do not see any bugs or tomato worms on any of the plants.
This looks like blossom end rot. I have included a website from colostate.