I don't have space Lyn.
Going to leave them out next year and put a thick layer of mulch over.
Hi Fred. You could as a precaution as the frost risk recedes cover the pots overnight with horticultural fleece. It’ll provide limited protection and remove the need to take them in every night.
My experience with leaving dahlias in the ground is that winter wet is as big an enemy as slugs and cold. Put all 3 together and your in trouble.
A lot depends on where you are and how sheltered a spot they’re in plus you need a bit of luck. I had Bishop of Llandaf in a planter survive the Beast from the East last year but I’ve checked them this year and they’ve turned to mush so go figure.
I tend to lift the ones I like and store in my attic over the winter. I then take cuttings from the tubers the following year. It’s really simple and there’s plenty of info online regarding the methodology.