Aad, While pumice has been the traditionally used medium, it is really not ideal for Worsleya in the earlier stages, especially the medium grade your seedling is in. I have found far better results using pure milled peat, even though that goes against what many have said in the past about the needs of Worselya. In pumice there are far too few fine particles for the small roots of a seedlings to come into contact with, which really slows it down (in my experience). There is a yahoo group dedicated specifically to Worsleya cultivation, I would highly recommend becomming a member there and posting your question to that community, as there are many highly skilled growers there that do not subscribe to the PBS list. By searching through old forum posts you should find answers to many of your questions, including those about fertilization. Heres the link to the group - http://groups.yahoo.com/neo/groups/…. Offers of much more reasonably priced Worselya seed appear on that list from time to time as well, a far better alternative than the very high ebay prices. Colin On Wed, Oct 9, 2013 at 5:06 AM, Nicholas plummer <nickplummer@gmail.com>wrote: > Hello Aad, > > I have not yet been fortunate enough to find Worsleya at a price I can > afford, but I do grow a lot of epiphytic and lithophytic orchids in > inorganic media like pumice and scoria. I would assume their requirements > are not entirely unlike those of Worsleya. The general rule of thumb for > fertilizing plants in inert media is "weakly, weekly." That is, you should > use a dilute solution of fertilizer on a regular schedule when the plant is > in active growth. If you use a concentrated mix, you will have problems > with salt buildup in the pumice as the fertilizer solution evaporates. If > you don't fertilize regularly, you'll have nutritional deficiencies. Try > to find a fertilizer that contains micronutrients, not just N-P-K. > > For epiphytes and lithophytes in inorganic mix, I dilute my fertilizer to > 1/4 the recommended concentration (or less) and try to remember to > fertilize at every second watering. On those days that the plants are > watered without fertilizer, flush the pot thoroughly with lots of water. > Ideally, use water with low mineral content. > > Hope this helps. > > Nick > > -- > Nicholas Plummer > nickplummer@gmail.com > Durham, North Carolina, Zone 7 > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ >