Becky,
Down here in south Florida, the Caladiums go dormant in the wintertime. This is similar to how they behave in their native habitat, where there is a distinct wet season followed by a dry season. When they do go dormant, that is the time to see if the tubers have multiplied and to change out the soil mix if necessary. If they have multiplied, you may want to replant each one in a separate pot, or move the group to a larger pot if they will all fit without crowding each other. You can also inspect for rot or bad areas on the tubers so they can be treated if necessary.
Spider plants don't go dormant like that; their "tubers" are actually fattened roots.
