Dear Leo, Thank you so much for your reply. I did locate the book that you suggested. Best wishes, Diana In a message dated 12/29/2009 1:06:18 P.M. Pacific Standard Time, leo@possi.org writes: Diana Fish wrote > Does anyone have an "organic" (ideally peat-free) growing > medium for a closed system terrarium--e.g. one that does > not use perlite? I have Begonia microsperma in a terrarium, > but was interested in general suggestions. I have an out-of-print older book on gesneriads called _The Miracle Houseplants_. The authors (whom I can't recall just now) write that one may use pure sphagnum moss, either living or the preparation called "green moss", as a substrate for most gesneriads. I would expect almost any other lithophytic, epiphytic, bog or forest-floor plant to do well in such a medium (which is very close to nature for such plants.) A big plus is that pure sphagnum is normally not host to fungus gnats. The book carries a very long subtitle. It's a great book though dated as to what plants were available then. It covers the tuberous gesneriads quite well. If you're looking for it online get the newer edition from the 1980s. There were several different publishings of the same text and photos, in different sizes and formats, from different publishing houses. The hardback should be available for under $10 including shipping and has better quality photo printing. Leo Martin Phoenix Arizona USA _______________________________________________ pbs mailing list pbs@lists.ibiblio.org http://pacificbulbsociety.org/list.php http://pacificbulbsociety.org/pbswiki/