Wintering over:

It depends on whether the caladiums that are wintered over were fed and watered well and grown in optimum soil conditions. Large, plump bulbs in the early summer may waste away by fall if they didn't get what they needed, just as daffodils and tulips will wane if not encouraged.

I dig and keep my old bulbs over and add new, too, so the border grows longer and more lush.

Nell

Similar to Studrose, I started caladium bulbs this spring. They took forever to come up, even at room temperature.

I planted outside for the summer, in pots. Despite being tropical, they did great for most of the summer (our summer temps are anywhere from 70's to 90's). A really neat addition to a mixed flower pot with impatiens, coleus, etc. Then, the cool nights of September (40's)seems to be taking a toll on them, they are getting droopy looking but still growing very slowly. So, I dug out my favorite ones and potted them up, and brought inside before frost.

Do they absolutely need a dormancy period? If so, does this involve actually digging out the bulb and storing it, similar to storing a begonia bulb, or can the plant just keep it's leaves but still go through it's dormancy period? Just like most houseplants actually stop growing a bit during winter and rest.

I suppose I have nothing to lose so I will just keep them lightly watered and give them a chance. If they don't sprout new leaves I have my answer. They were actually still getting some new leaves when I transplanted them and took them outside so hopefully these leaves will continue to unfold.

Glen

If you pot them up now, bring indoor, water once and withold the water after that, they'll go into dormancy within a month or so. Start watering them with 1/2 strenghts Miracle-gro around Christmas and within 50-60 days you'll have this:
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Alternatively, you may continue to water them (sparingly) and they will grow for you indoor whole winter, but in February-March you have to stop watering completely, let them go dormant for a month and start watering again. In this case by May they'll be ready for outdoor living.
Keep in mind that once soil temperature drop below 48-50F tubers will be killed instantly, so if yours growing in ground, it's about time to do something with them.