Generally the tubers are not considered hardy in the ground over winter below zone 7. Even in milder climates, they are often dug and stored to prevent rotting from excess moisture in winter soils.

Wait until a good frost has killed back the foliage, After that has happened, cut that off just above the soil level and compost or whatever. Gently dig the tubers out of the soil and wash off all the dirt. While still damp, wrap each tuber in several sheets of newspaper. Store for winter somewhere cool, dark and dry - root cellar, unheated corner of the basement, in the garage, etc.

There are other methods of storage - burying in sawdust or peat moss, vermiculite, etc. - and all work about as well. It is important that each tuber is kept separate, so a layer of storage material completely surrounding each one. If they are all piled on each other, they can rot. And they need to stay just barely moist - that's why you should wrap them or store them while still damp (not wet) from their bath. If allowed to desiccate or dry out too much, they will not be viable next season. It is also important to keep them quite cool but above freezing. Too warm and they will begin to sprout too soon.

Thank you. That's great information!

I did not dig my dahlias up last winter and they survived. They were in a pot last year. A friend gave me the tuber. Mid winter I realized I had not protected them. I dumped the whole pot - a big one that holds about 3 cubic feet of potting soil. Then I put a big pile of mulch over that mound. I didn't expect them to survive and was surprised to see a sprout this spring. I am not recommending this method because it is risky, but sometimes stuff I bring inside rots so at my house that is risky also.

I live in zone 7, Tulsa, and mine came back. I am hoping they come back next year. I tried to buy some last weekend, but was told they are sold in the spring. Maybe I was just lucky that they (2) came back.

Sammy

I don't dig mine....and after a few years, they are absolutely bloody massive - I can truly see why they have been grown as a food crop. I never considered this to be a major disadvantage but this year, the beds have burst out of their bounds and action must be taken.....so I am going for the bucket of sand and old seed compost medium, packed away under the greenhouse staging.....I hate doing this winter storage lark though.........

....mine have never come back. I would definitely dig them if you want to save them.

Lisa

WOW thanks this one is huge this yr. maybe I'll mulch it good and see what happens. I've given bouquets to all the
neighbors and there are still loads of flowers on it.
Thanks for the info folks.