I've read the threads about people planting their dahlias in pots in the ground and then digging and storing them that way. I just can't believe that a 4" pot is big enough for some of the tubers I've seen develop in my garden, so I've started all of mine in cut-off milk jugs with holes cut in the bottoms for drainage. My plan is to plant them jug and all in the garden and then very carefully dig and store them in the cartons over the winter next winter. They should be ready to just set out and start in the spring next year, saving the whole potting thing to get a jump on the season in my cold climate. The plastic shouldn't get brittle since they won't be in the sunlight and if I'm really careful in digging them, will this work?