I've never grown potatoes before, but lately I'm obsessed with the idea of growing sweet potatoes. I'm in zone 6. Is it too late to give this a shot? Secondly, I've heard all sorts of crazy potato-growing ideas, from barrels to tires to plastic bags. Are any of these methods suitable for sweet potatoes, and, if so, could anyone direct me to good info on how to do it? I'm looking to plant them (if not too late) outside of my raised veggie bed. Thanks!