I have three tomato plants, which, long boring story short, sprouted in Winter. They've been living on my windowsill and they look great, much better than my first attempt at tomatoes last year. It's getting to Spring now and I was planning to put them outside. I think they'll survive outside with slow hardening off, my dad agrees but my mum doesn't. But it occurred to me, it might be nice to have tomatoes kept at perennials on my windowsill. I totally don't mind the impracticality of having such large plants inside. Unfortunately I don't know the variety but they're either a roma or grosse lisse. They're about 2-3 feet tall and starting to fruit. But anyway, my main question is, what size pot should I be looking for if I want to keep them inside? Right now one is in a pot about 25cm (10in) across and and the other two in pots about 20cm (8in). Last year I kept some in square pots about 2x2x2 feet but I watered them really badly and the roots didn't go very deep, so I have no ida how much room they need for their roots.