I don't usually lift mine, they overwinter here fine in the ground as we have very mild winters. The only time I lift is when I want to divide a clump that's gotten too big.

I dig the tubers up when the foliage has died down, let them dry for a day or 2, brush as much dirt off as possible and place tubers into polystyrene boxes (the kind produce is transported in) in single layers.

I store the boxes in my garden shed - it's dry but colder than our garage. Some people insist you must dust with a fungicide, but I've found that as long as the tubers are dry before storing, I have very few that rot.

As for replanting, I wait till I see little green shoots appearing on the tubers in early spring, then pop them in where ever I want to plant them. A bit like spuds really!

Others will probably have a slightly different way of dealing with them that's more appropriate to your climate -what zone are you in?

Check the Dahlia Forum. They have FAQ's that should contain the information you want. If not, they'll be glad to answer your question.

I don't lift mine either, they manage with our winter wet and occasional snow without damage. My neighbor does have a lot of dahlias and only lifts in Fall when she wants to divide certain clumps....

but this is a Z8...need to know what zone you are in.

Since we don't know your zone we can't tell if you need to lift the dahlias or not.

If you do then simply remove everything other than the tuber, let it dry in the air for an hour or so and then stick in a plastic bag of peat or cedar chips. Seal the bag and place this in a paper bag to keep out light. Store in the basement or other cool place.

To this some folks will dust them with an anti fungal agent to help prevent rot.

I DO NOT recommend storing these in a plastic bag - the bag does not allow the tuber to breathe and they are extremely likely to develop rot. You can store the tubers directly in very slightly moistened peat or bark/wood chips or wrap the tubers in newsprint and store in a cardboard carton in a cool, dark location. If stored in loose peat, avoid letting the tubers touch, as this can also encourage the development of rots.