Inspired by the unexpected sweet potato at the bottom of pot filled with annuals at the end of the summer (see next image), I decided to grow a sweet potato vine by inserting some toothpicks in an organic sweet potato and suspending it in a glass of water (because it wouldn't have been treated with an anti-sprouting chemical) and after a month of so, roots started to grow, followed by sprouts.

Realizing that the growth would peter out if some nutrients weren't deliver, I potted it in this small pot and growth rate increased. It's looking like I'm going to have to put it in a larger pot.

Following what I've learned on the web, sweet potato plants are started from cuttings taken when the greenhouse started plants are pruned. This seems to be a bush rather than vining type potato so it might be easier to grow. Since my flower pot that was mostly in shade yielded some potatoes I'm hoping to harvest some from this starter, next fall. The plants will be lucky to get even 6 hours of sun, but it's worth a try, just for the fun of it.