Mine are sprouting too. They are stored in peat moss in a garage at about 50 deg. Here in the Denver area we have a short season so I start mine in pots when they develop sprouts. I have to start them in February anyway to get them big enough by the first June to put out, so it's not that much too early.

I just put them in a south window until they get going real well, then I put them under lights. When the spring weather gets mild I start acclimating them during nice weather. I plant them out mid-May if they get too big for inside, put tomato cages around them and cover them with row cover. We short season people have to work hard to keep our cannas.

It would be interesting to hear from experts whether one could cut off the sprouts to slow them down.