I'd remove them from the baggies. That could cause them to mildew and rot.

Here, of course, we leave them in the ground for the next generation or three to deal with, but I think Tony's right;
don't seal them inside anything.

...about leaving the clumps intact over the winter.

Here is a link that might be useful: when to divide cannas

Thanks everyone. I was beginning to think many of you had put this forum into hybernation until next season.

I think its safe to say that I'll probably lose some - especially the small ones.

The ones in baggies weren't sealed; they were left open but stored in a cardboard box with lid. My attempt was to keep them from touching (all grouped together) with some peat moss. At the time of digging they been hit with a pretty good frost at least twice.

The entire clumps I put in plastic bags, with a bit of cocoa mulch and did not seal the bags.

Now I'm dealing with temperature fluctuations. Basement temperature will probably be too high and garage temperature most likely too cold.

I've thought about bulding some kind of "holding box" and putting a low energy lightbulb in it in an attempt to keep the temperature above freezing through the winter.

Hi flower217, I have stored my canna in large plastic storage bins, I cover the rhizomes with peat moss and leave the lid lose for a month or so until dry, and then i cover with lid. I store them in my basement, I have had very good success with this method, and have lost nothing of any consequence. Hope this helps you. Hank....

If your tuber collection is not very large, you may consider moving them into the fridge if you have room... I have kept small tubers in a cardboard box filled with woodchips, and placed them in ziplock bags filled with woodchips or peat moss. Had very good success with that and did not loose very much.

I got my cannas from my mother. They are now nearly 40 years old. I grew up in Michigan watching her dig them up every year. After about 30 years I'd say she finally perfected a simple process with very nearly a 100% survival rate. This is what you do-
First off, we had an attached garage. (if you don't, there are options) My father ran a furnace duct into it to give it just one heat vent. This kept the 3-car garage above 40* all Winter. Perfect for the cannas. If a heated garage is not an option, I've heard of people building insulated boxes with light bulbs and such instead. Personally, I would just rescue an old refrigerator from a landfill and put a common heating pad in it. Or a bird bath heater, or I might bypass the light switch in the door so it's own light never goes off. Whatever. Just keep them above 40*.
Well she would dig them up, rinse off all the soil and dip them in a common fungicidal solution available in most nurseries.
She also bought a cheap paper shredder that sits over the waste basket at her desk. She not only has way too much fun with it, she found that shredded junk mail and news paper was better than peat moss, mulch, or soil for storing bulbs and tubers. It's also free.
She put the bulbs in layers of shredded paper inside stacks of milk crates. She liked her bulbs to be at least the size of her foot before she would consider dividing. The bigger the bulb, the bigger the plant would be. She also hung a spray bottle of mostly water with a little garden fungicide on the stack of crates. She would mist them all down every few weeks or whenever she thought about it. Just to keep it all about as moist as a pile of leaves on a forest floor. Not soggy. Humid. The latticed milk crates and shredded paper offered plenty of air circulation while her infrequent spraying kept them moist and mildew-free. Each Spring they came out looking as if they had just been dug up the day before, plump, shiny and purple. The large foot-sized bulbs always grew into plants that were 7-9 feet tall, several inches above the gutters. (Miracle Gro, hint-hint)

Wow, panspipes, great information! It's an old posting (late 2010) but the storage question never goes away. You can't argue with decades of success.

In zone 5, for me, it's either dehydration or mold. Very difficult to hit middle ground. Once in a while I luck out. Canna and dahlia are both difficult for me. We have an attached garage with an old refrigerator in it, so you'd think eventually I'd learn how to do this! Thanks for the info.

Well Claydirt, any common garden fungicide will keep your tubers fungus-free. And if you can't remember to moisten them every few weeks, try setting the calendar in your email to remind you. (yahoo mail has this function.) If you can't get to it right away, keep marking the reminder "unread" until you can. Also, if it's in a refrigerator or any other type of well sealed cabinet, maybe just a tray of wet sponges kept in the bottom to act as a humidifier. You can also buy small humidifiers that people use in large humidors to keep their cigars from drying out. It may be a little costly, but it would be a one-time expense for a nearly fully automated tuber humidor. "Tubidor". D*mn I'm good. Maybe I should just make them and sell them. lol ;)

Below is a video that shows how to make a humidor out of a refrigerator.
The man is amazingly irritating to listen to, but you can skip the first 4min-20sec of rambling. He just lined a fridge with wood and put a 'Cigar Oasis' electronic humidifier in the bottom. I don't see why this wouldn't work for tuber storage. The units are about $100 and they come preset at 70% humidity, but you can turn it up if you need to. They only need to be filled every 6-8 weeks. Doesn't get much easier than that, Folks. :) And if you don't have $100, well all the humidifier is is a box of water with a tiny fan blowing on it. I'm sure you can whip something up. And if you don't have an old fridge, try an old trunk, junky armoire, or an old locker or something. Look on craigslist. You'll find something. If you make one, show us the pictures!

Here is a link that might be useful: youtube