A.J.Hicks, author, seed projector, ex-smoke jumper magnanimously replied: "A clever idea, but (tragically) not novel. Arditti mentions this in one of his books; I think it was Ernst who tried graphite as a substitute for charcoal, and the effects weren't nearly as good. Ergo, there's something more to charcoal. :-)"
And Ray Barkalow, purveyor of plants, supplies and wisdom added to the discussion: "The reason any charcoal "absorbs" - or in reality adsorbs - stuff is due to the presence of pockets of small crevices and high porosity. It is the presence of those tiny regions of large surface area that permit molecules to adsorb. The size of the molecule and the size of the porosity are the primary controlling factors as to what sticks and what doesn't. In truly activated charcoal, the percentage of such porosity is very high, making the accompanying surface area huge - in the neighborhood of 500 to 1000 square meters per gram - so it can adsorb large volumes. In horticultural charcoal, only small portions of the pieces are truly "activated," so adsorption is far less. Graphite, tending to be plate-like in structure, with the flat surfaces stacked against each other, has little surface area by comparison. Interestingly enough though, if I recall correctly, in activated carbon, the surfaces are very much like graphite, but again, it's a surface area per unit volume thing." Now for a question from the unenlightened: Why are we putting charcoal into media in the first place? Is it being done to "darken" at the roots, to provide a "more natural" environment? (As if there were anything inherently "natural" about orchids growing in carbon-and-mineral-supplemented Japanese jelly). Or are we adding charcoal to act as a reservoir of substances that are toxic to orchid roots in high concentration in solution but are exhausted before inflask growth is completed - so they leach off the charcoal as the local concentration diminishes by incorporation into the growing plant? Or is charcoal simply, as Aaron implies, "magic" ;^)? And, lastly, but probably most importantly, Can the OGD support a non-political discussion of orchid related matters anymore????? On a completely unrelated note: How "nanum" is Oncidium nanum? The one I bought in Baton Rouge recently has leaves of about 8.5 inches/21.6 cm in length. Also, what conditions does it favor. I grow a couple of other mule- ear oncidiums and they seem to be happy with fairly high light and very warm conditions and high humidity - the only kind we seem to have in New Orleans. Does this one like the same? I have been looking to replace a miniature mule ear that I had years ago and lost (in a freeze back when I lived where one had such things), it was named Oncidium auris-assinorum. I loved both the plant and the name and would appreciate any information anyone here could provide regarding where I might find a replacement. Orchidaceously, Marquis Hodes ____________ Virus checked by Guardian Worm Killer && AntiVirus Version: AVK 14.0.1416 from 15.07.2004 Virus news: www.guardianproducts.com
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