Question
Dear  LIG: I dug up both my cannas and callas (I usually forget and winter takes
its toll) and am storing them in my unheated greenhouse.  Now what do I do
with them?  I live in mid-Michigan: zone 4 or 5 depending on which catalogue I
buy from and have a cool basement to store bulbs in.  How do I prepare the
bulbs for their winter sojurn?

Answer
As you know, Frank, since Cannas and Callas are tender perennials, you must bring them indoors for the winter.  

Funny how we plan to do that and often miss the boat.  I guess we've both been there done that.

Let's start with Cannas.

Begin by removing the dead and dying leaves and soil.  The usual routine for storage is to bury them, shallow, in sand or vermiculite.  The Canna "crown" should be just peeking through.

Spray the surface with a spray bottle of water and store in a paper bag - NEVER in plastic (they'll rot) - in
a chilly basement or garage.  You should spray them with water regularly to keep them from drying out, the same procedure as with Dahlias.

The temperature should never reach 32 degrees F.  Or you can kiss them goodbye.

Watch for new growth and in the late spring, after all possible chance of frost has passed, carry them back outside to your garden and plant as usual.

Your Calla Lilies should also be stored in a cool, dry place for the winter.

Brush soil off the Callas and put them out in the window to dry in the sun.  A few days later, put them in storage in a cool, dark, well-ventilated spot in your basement or garage.  Some growers overwinter these in peat moss.  Some have their own custom mixture.

Potted in autumn, dormant Calla rhizomes will form roots if you keep them moist and keep them 50 degrees F.

They need less water over the winter.  But don't let them dry out.

One of the major Calla Lily specialists, FlowersBulbs.com
(www.calla-lilies.com/index.cfm), recommends treating these with a Fungicide to maximize your odds of success:

"Wash tubers gently to remove soil.  Then dip tubers in an
appropriate fungicide solution (e.g. Kocide) for 5-10 minutes.  This helps to eliminate fungal pathogens.  Dry tubers within 4-6 hours with air assisted fans if need be. Subsequently cure bulbs for 3-7 days at 70-80癋, ensuring good air movement.  This curing stage is important in forming an outer skin on the tuber, which acts as a barrier to dehydration and disease. Store tubers in a single layer on mesh trays at 45-50癋 for a minimum of two months prior subsequent plantings."

Of course, they are a big grower; a fungus epidemic would be an economic disaster for them.  So I think you can safely skip the part about treatments with fungicide - in fact, it is probably MUCH better to do that, because that stuff is strong and who knows what weird side effects you'll end up with down the road?

But the curing and air movement is a tricky exercise, one that will come in handy, with a few small custom changes, with Dahlias, Gladiolus and other tender bulbs.  It's a long term, all-winter-long care project.  And not foolproof.

Remember: If you don't succeed at first, it's still a learning experience.  Let me know how this goes.