using non seed potatoes ?

I was transplanting some peppermint and when I dug in the ground I found some potatoes from potato plants that had been growing there. I am not sure if these plants came originally from seed potatoes or not, they may well have not but I can't remember. I had not been very serious about growing potatoes but I saw some youtube videos and I am thinking of trying it in containers. What's the worst thing that could happen using these potatoes to grow from ?

Can I start them indoors in zone 6 in early winter or maybe I should wait until march ? The room where they would grow is a cold part of the house. It's always well above freezing but it can be 50 degrees in there easily for several days  

my seeds potatoes are whatever i didn't eat over teh winter ;-)

i have grown potatoes from sprouting old potatoes that were no bigger than a hazlenut - i even got a few off and old box far back in cold storage that i totally forgot about until the NEXT spring.. 15 months - there were mostly skeletal with a few small "tubers that tried" - which, when in soil, grew..

so don't worry about non-seed potatoes!!

as for starting them - are you planning on doing them in pots? if so .. split them plant half now and half in the spring... i did a few this fall to "be there" in the spring just to see.. i get volunteer spuds all teh time.

hope this helps - great find - volunteer/surprise plantings are the best fun!!