Aad, I would like to second Colin's comments, especially those about growing seedlings at the earlier stages in something other than pumice, such as some form of well-draining peat. Unless you can keep young seedlings in an environment for several years that is quite humid all the time and they receive frequent watering during the warmer season, but that the seedlings never experience having wet roots for any extended period. I have had quite a bit of experience trying to use small pumice at the early seedling stage, and in my southern California climate, they never did that well until I switched to, in my case, long fiber peat. This was first discovered by a couple of people in South Africa who are on the Worsleya list Colin mentioned. Adolescent and mature bulbs need an extremely well-draining medium such as pumice, scoria, or fly ash. Colin is correct in suggesting a look through the archives of that list for a lot of good information that answers your other questions. --Lee Poulsen Pasadena, California, USA - USDA Zone 10a Latitude 34°N, Altitude 1150 ft/350 m On Oct 9, 2013, at 9:28 AM, Colin Davis <codavis@ucdavis.edu> wrote: > 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 >