I have a huge perennial garden with over 300 dahlia bulbs that have all bloomed. I know it is best to wait until after the first good freeze to dig them out of the ground. However, I must leave the state in 10 days and if we do not have a freeze before then, what can I do? Dig them up anyway, bag them as I always do and put them in the cool basement? Dig them up, leave as much dirt on them as possible, bag and leave them outside until after the first freeze, and then have a friend move them to the basement, maybe put them in the freezer for an hour or two and them move them to the basemen???? HELP! I know leaving them in the ground will cause them to rot. I don't want that. HELP! I will appreciate any suggestions you might have. Cliff Stiles, M.D. email@example.com or 320-968-7233 THANK YOU VERY MUCH!!
According to the U of M info below, you can dig them after there is frost damage, not necessarily a good freeze.. You are further north than we are and we've had a damaging frost but no freeze. Perhaps you have also?
If you have any frost damage, go ahead and dig them as usual. If not, the reason to leave them until after a frost is that the tubers continue to grow and develop until the frost, giving you better tubers. That said, they may not grow much between your digging and the first frost. For that reason, I would go ahead and dig them right before you leave.
I also suggest that you contact the Minnesota Dahlia Society. They have a web site http://minnesotadahliasociety.org/ with a contact page where you can leave a message. Someone in that organization may have experience in digging dahlias a bit early.
Best of luck.