Hardy here, so close but yet so far?

For use in eating, the ideal is to cure at 85F and 90% humidity for 5-7 days, then store at 55-60F and 90% humidity in a well ventilated and dark location. Lower than 55F and the tubers may die and fail to re-sprout; higher than 60 and they may sprout or rot. An unheated basement might be ideal in our climate, just be sure not to let the temp drop too far.

The curing process is mostly to heal any wounds taken in harvest and to convert starches to sugar, so for an ornamental plant in a pot or very carefully dug. you can probably skip that step.

If it's in a pot and you have a 55-60F place, I might just bring the whole thing indoors.