Looks like Blossom Bottom Rot. Don’t let your soil dry out if you can help it. Easily recoverable on further fruit if treated.
Thanks! They are thirsty beasts. I water every day but I guess I need to up my game.
How are you watering? I used to spray my tomato plants with a shower-end hose but had much better results from just sitting the hose on the soil and watering the soil. Less water is lost to evaporation and it also reduces the chance of fungus in the leaves.
Not really contributing much with this, but I agree with your assessment. From what I understand you should also remove any dead blooms that didn’t just fall off as well.
Correct me if I’m wrong, but blossom end rot doesn’t ruin the whole fruit, but just makes it undesirable.