I believe they have to be kept above the freezing point. They are tropical plants. I overwintered mine in a laundry room last year which got pretty cool (45-50'F.) and it died over the winter. The bulb became soft and rotted. I'm not sure why.

I just bought one on sale in a gallon pot. I wonder if I replant it into a larger pot and use it as a houseplant over winter if it would survive. Anyone?

Please describe what I must do to my Caldium roots/bulbs for the winter.

EE can be overwintered here in zone 5 different ways.
It depends on your type of EE.
esculenta - big bulb- fine to bare root in cool basement
esculenta-small bulb- good luck- mine usually die
black magic- houseplant- and it barely hangs on til spring in a bright window. usually down to it's last leaf.- get's leaf burn if touching freezing window.
odora- fine as housplant- splendid!
portodora-fine as a housplant as well- lovely!
maccrorhiza- fine as houseplant

hope it helps!
karen

I have my elephant ear in a pot and bring it in for the winter next to a sunny window and it does ok and makes a decent house plant. I have had it for 3 years now. Being in a pot it seems to have a limit as to how many leaves it can have. When a new one comes often an older one has to go. The number is less indoors. I have some very nice white and green caladium in a pot outside this year and am wondering if I can do the same thing.

EEs (alocasias and/or colocasias) are aroids. There are some threads on that forum discussing overwintering them. Suggestions are that if potted, stop watering, allow foliage to die back, store indoors in a cool dark room, like basement, garage, etc. If you want to dig them up, remove the dirt, allow them to dry out, store them in peat moss in cool, dark room over winter, and plant them out again after all danger of frost has passed.

They can be overwintered indoors in a sunny window, sun room, etc., but I am told (on the forum) that they can get kind of bedraggled by winter's end. However, they will do better when the weather warms (after frost date has passed) and days and nights are warm and temps consistent. Late spring is also good time to repot. Fertilize with high phosphorous fertilizer. Check out the aroid forum and gallery. You'll see some great indoor photos of these plants.

Susan