In mild areas, leave dahlias in the ground under a thick mulch of compost and chipped bark. If your garden has heavy clay soil or frequent frosts, it’s best to lift and store the tubers.
DIG THEM OUT Dig around the clump with a garden fork, taking care not to spike the tubers. Lever them out carefully. Shorten the stems down to about 5-10cm (2-4in) from the crown.
CLEAN THEM UP Remove as much soil as possible, using a stick to reach into the nooks and crannies. Turn the tubers upside down and leave in a dry, frost-free place for a couple of weeks so they can dry off naturally.
PACK THEM AWAY Pack tubers into crates or large pots and fill around the sides with newspaper, sawdust or compost. Overwinter in a dry, frost-free shed or garage. Check occasionally and remove any tubers showing signs of rot. Repot in early spring.