I kid you not--these came from my front-yard garden, and some pots on our stairs all summer! Can you believe it? City spuds? :) I almost forgot about them, they looked like an uglier version of the decorative sweet potato vines people grow for looks. They were wound in around my tomatoes and curving all over my stairs. (The big ones came from the plant that got a lot of sun and was in the ground). But the little ones from the pots did well enough that I will actually bother next summer.
I started them from slips in May. To find somewhere to buy them I had my mom ask around in Lancaster at nurseries and people she knew who might know. Then we drove down a rural road in Lancaster where she heard that an Amish farmer sold them until we saw a sign outside of a farm advertising them. It was a culturally surreal experience. We pulled up to their house around lunchtime and didn't see anyone around. One of the kids came outside to ask if she could help us and then told us to knock on the door of the smaller house right next to theirs where her grandparents lived. So then her grandmother graciously interrupted her dinnertime (usually the big meal of the day for Lancaster farmers) to pull us some slips growing behind her house for a very modest price. I actually bought more than I should have because they were so cheap--which led to the temptation to put in too many per pot. Next year, one to two, MAX!
I have two pots left to harvest yet, I just need to beat the frost. Overall, considering my expectations of tiny potato marbles only, a smashing success.