Depends. Usually crops will grow better if there are people around (so that the "chunks" (play area if you will) are loaded) and actually reacting. So with that in mind I'd say that your chances are better in town than the wasteland. Then there' something else to consider: in town your crops are fully safe, but in the wasteland they're unprotected. Meaning that they could be griefed easily. And I'm not pointing my fingers at other players; but what about mobs which trample over it, or a creeper which doesn't want to eat its vegetables and protests by going b00m? So my suggestion would be to use town if you want to be safe
