I have a few tomato plants in containers on my roof that are producing small fruit with big ugly brown stains on the bottom. The leaves towards the bottom are turning yellow. Is this a watering issue? Is there such a thing as too much sun? How can I nurse my plants back to health?
Small Tomatoes With Big Ugly Brown Stains on Bottom
Certified GKH Gardening Expert
This article will help: https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-blossom-rot.htm
You've got blossum-end rot. You can search online for days and days and find so many people with so many theories as to the cause. I've finally come to the conclusion, "If I've added egg shells for calcium, trace elements for all the other minor minerals that can be depleted, and keep it water, but it still comes, there's nothing else I can do." If it's too big to eat the tomato, take them off the vine. (You don't want the plant to waste energy fueling something you won't eat.) If it's just on the bottom, when they're ripe, cut that off before you eat them. You haven't lost your crop, you will merely have an unsightly crop.
So far I've learned that plum tomatoes are the most susceptible (bummer, since they're the meatiest), cherries and grapes seem to be okay, and large tomatoes are hit or miss. Ultimately, it's trial and error, and, despite what people say, no one really knows the cause - just the depression. Sorry, but the good news is, we never went tomatoless because of that problem, and we have had bad years with that very problem.