please advise best way to keep non-stop begonia's over winter. thanks

Two sorts of begonia Dave. Fibrous rooted.... treated as a one season bedding plant. Tubered..... the tuber can be stored in a frost free place and planted next year in garden, pot or basket. They run out of flower or whither if there is frost, dry them off. I store in onion nets labelled as to colour and habit.

'Nonstop' is a tuberous type, Dave, so you can follow Dorjac's directions for the tubers.