This is my first season trying to grow tomatoes. I bought three different types (cherry, heirloom, and super sweet), and planted them in a large pot on my porch. They seem to be getting a lot of sunshine, and the soil is mildly moist. They're starting to develop yellow leaves with brown spots and some of the smaller branches are dying.
Do they need Epsom salt or are they getting too much water? Do I need to move them to their own pots?