Either cut them back, take them out of their pots, wrap the rootballs in damp newspaper and store them dryish in a frost-free place, then pot and start them off again in the Spring, or - I kept some of mine going right through the winter in a frost-free greenhouse. You could also take some indoors onto a bright windowsill, where they'd be happy.

This question perplexes me. Why would anyone want/need to store geraniums over winter? Are they in some situation where they are vulnerable? All my geraniums live happily in the garden soil all year round. It would be an absolutely mammoth operation to dig them all up, pot them, buy a greenhouse, and then do it all in reverse come spring. I must be missing something - I wonder what?

I'm assuming that this guest refers to Pelargoniums, Bernard. A lot of people call them 'Geraniums'.

I winter some of mine in my south facing porch, they are very happy in there. They get little water and always bounce back in the spring with re-newed growth and fresh soil.

I overwintered mine in their very large pots in a double fleece tent huddled up together under a canopy and in a small plastic 'thingy' up against the house wall last winter. Nearly all survived and have given me a wonderful display since May. If anything they are at their best at the moment. Plus the fuschias that survived too. If you have a lot of them or rooted cuttings look at Four Seasons posting about taking over a neighbours overgrown plot to overwinter tender plants.