begonia

It depends what kind they are.  If they are tuberous begonias, I wait until it starts to get cold, snap teh stems off them and rub the roots of them.  Then I leave them on some newspaper in a dry place for a couple of days to let them dry off.  After that I wrap them in newspapers and put them in a box in a cool, (but frost free), dark place until the spring and I plant them up and let them grow again.  I have used the same tubours for many years and sometimes have to cut a tuber in half because I don't have a pot big enough!