If you have light, free-draining soil you might not have to lift them. Tubers on heavy soil will tend to rot off. So if you want to lift and store them, you need to let the early frosts burn off the tops. Then lift and let them dry out and remove the soil and dead foliage. Find a deep container and store in dry sand, peaty compost or wood shavings in a dark frost-free environment. Please, don't forget to label them before storing especially if you want to take cuttings in the spring.

If you're in the southern third of the country, I'd leave them in the ground. However, a cautionary tale - I stored mine in the shed last winter and the mice ate the lot! And it turned out to be such a mild winter they'd have been fine left in the ground. tut.

I left mine in the ground last year expecting to never see them again. Well, they are in full bloom now & looking dandy. I actually divided one in the Spring. I will never dig another dahlia again. I just mulch over them with a couple inches of fallen leaves - it's like a blankie for nappy time.

The tubers I tried to store in my basement the previous year turned to dust by February.

Thanks for all your advice friends :o))

Errr! I shredded a load of branches, could I use those as a blanket over my Dahlia's?

In this instance, I think the leaves provide better protection. You don't have to shred them either, just leave them whole. They will provide layers upon layers of protection, like a quilted blankie for nappy time :). The dried autumn leaves will also hold in just the right amount of moisture, preventing the dahlia tubers from turning to dust by February - like mine did in the basement. They also enrich the soil as they decompose...and the earthworms will have a blankie too.

Thanks Bathgate :o))