in the past I have frozen them and bottled them successfully. I tried burying them in sand and leaving in a cold coalhouse. not too good all shrivelled or mouldy by jan.

i always leave mine in the garden, and just dig them up as needed, mine survived quite happily last year in the snow, my soil is very light so perhaps that may help, although i must admit that if we get a very wet year it can rot the bottoms if i'm unlucky