I had thought of a roof garden...I have a flat topped garage that is in the back. I'd have to create an easy way for me to get up there to tend to it, but I never got around to trying it. I've never seen fence or railing gardens! I might have to check into that option as well. There's nothing like fresh vegetables from your own garden or a meal that you've cooked that you started from seedling. Thanks for the ideas!