My back porch is enclosed and has a see through roof. I have three raised beds for growing. I start tomatoes in like March or April and, last year, they lasted through December. There is also lettuce and some other stuff. Right now I am making a run at red cabbage, parsnips and radishes. Nothing has died yet and there is no heat back there. The current temps run from around 35 to 48. They are not growing real fast. I have got some seeds for giant tomatoes I am going to try when spring arrives. The strange thing is that my wife loves tomatoes and I am not quite so fond of them.