I mentioned my balcony-based orchid growing habits to Johan Gauché from the EPOS, who kindly sent me some scans of an interesting article from the 2004 edition of the South African Orchid Council's publication, Orchids South Africa. The article is entitled "The Hanging Gardens of Melville" by James Sonnenberger.
Having moved from East London to Melville in Johannesburg in the mid 1990s (leaving his orchid collection behind) the author tells us of his reintroduction to orchid culture in his second floor flat through a request for a white Cattleya for a bridal bouquet at his florist business. Now he has a fairly diverse collection not only on his (semi-open) balcony, but on every available windowsill too!
It looks like the author is taking the challenges of balcony culture in his stride, harsh frosts aside, and is doing well in flower shows with his specimens. As our balcony is totally enclosed with windows and a small electric heater dispenses with any risk of frost, I suspect stifling summer heat, rather than winter cold will be our continued challenge!