My tomatoes, especially my paste varieties Opalka and San Marzano, often rot before fully ripe. This seems to happen whether I ripen on or off the vine.
One day they’re ALMOST ripe, next day, liquid falls out when I pick them up.
What gives?
How is the foliage? Sounds like late blight.
That has happened to me when it has been raining non-stop. The only tomatoes I’ve been able to harvest this year are green zebra and a variety of cherry tomatoes. Have you been in the rain zone?
We did get a lot of rain, but it’s been dry for over a week. August total only about 3.7” so far. July was around 9”.