In October (maybe November), I dug out the tubers 2 weeks after the killing frost, and I washed them off, dried them and then packed them with peat moss in a box and stored them in my basement. I checked on them once, and they looked OK.
Well, I pulled them out yesterday and I was so dismayed. This is what I found:
The first two tubers to come out of the box were shriveled and desiccated. However, as I continued to reach in the box, the rest of them looked OK:
They had even begun to send out shoots! So I used a bunch of old containers to lay them in and covered them with some moist potting soil - being sure to let the shoots show, and stuck them under the grow lights. I have 5 of them. I have no idea which is which, because I didn't keep track to them very well. I have since leaned that you can actually write the name of the dahlia right on the tuber with a Sharpie.
After just 2 days, the sprouts started to turn red:
Here they are, a week and a half later, outside and growing steadily:
All of my new dahlia tubers are still in the box from Swan Island. I will put them out when the days and nights are warmer. Then, in September, I will determine whether or not it's worth potting them ahead.