I'm going to try to email you with info. There are a couple of options available to you. And no, if you are in Zone 5 you have lots of time yet to grow your own slips, provided you act quickly to buy seedstock.

Are you looking for ornamental varieties or plain old eating types of sweet potatoes.

If you're looking for the edible ones I will have some slips soon if you would like to trade. They're not up yet, but the roots are forming and I expect to see them any day now. I can root some slips when they appear and towards the end of April, when the weather is warm enough to mail them I should have several.

I would debate weather or not you have enough time to start now. I start mine in the first week of March and it takes at least two months before I have rooted plants. I would also say that January is way too early to start too. But that's just my opinion - maybe I'm slower or faster than other growers :-)

BP