Q.Brown On The Bottom
I’m growing two roma tomato plants on my 11th floor balcony in the city in a garden box (just these two plants in one planter). I have about ten tomatoes about the size of a quarter now and the plants themselves are almost 2′ tall, but I noticed today that the bottom side is a brownish color. Why is this, and are the tomatoes OK? I’m watering them everyday. I used to have a big garden in the country and have never seen this before.

Certified GKH Gardening Expert
This is bottom end rot. This article will help:
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-blossom-rot.htm