Part of pushing boundaries is finding where they are, and the physical evidence of that boundary is shown above - blossom end rot, caused when the plant runs out of water and nutrients before it can complete the fruit. Low fruit levels, some plant failure, yellowing and other signs of struggle are here and there too -- especially on the seven plants I put in small pots and on top of a wall in the shadiest corner of the garden (I had about thirty plants, all of fairly delicate heritage varieties).
But even they have fruited. Tomatoes are brutes. They can take bad treatment, and come back fruiting. And next year I'll know about tomatoes in pots in my garden:
- Yes please on sun but not on wind -- it dries them too fast
- You're going to need a bigger pot, and one plant in one pot. You can't underplant with anything. Sorry.
- They will do better under glass, sorry.
- Tie in early and feed and water regularly.