Stop putting one tomato plant per pot, it is killing your harvest on a small balcony
I see so many people on here post a single sad tomato in a 12 inch pot and then wonder why they get 3 fruits all summer. Last year on my south facing balcony in Boise I planted two cherry tomatoes in one 15 gallon fabric pot with a basil start tucked in the middle, and I pulled 90 tomatoes off that thing by Labor Day. A single lonely plant in a big pot just bakes its own roots in the afternoon sun, while two plants shade the soil and each other. Give them a cage, water deep, and stop babying them. What is the smallest pot you have actually gotten a real harvest out of?