Hildegard Crous stated: "I get excellent root development on terrestrial orchids if the plants are initially on a clear medium, (1/2 MS) and then replated onto the same medium but containing charcoal. However, with the follow up replate, (charcoal added to the medium), the plants lose colour, (pH drops and leaves turn white, ) probably because the charcoal has adsorbed some critical nutrients."
I wonder if you couldn't get the "darkening at the roots" effect that charcoal provides without the non-specific adsorption/absorption problems by using an alternate insoluble, dark pigmented carbon compound. What I would tentatively suggest for this purpose is graphite which I think (but don't know for sure) is relatively inert and doesn't adsorb the way charcoal does. How's that, substitute one artists' drawing medium for another? If you try this, and it works well, please remember to credit me with the idea (in the unlikely event it turns out to be unique). Best of luck, Marquis ____________ Virus checked by Guardian Worm Killer && AntiVirus Version: AVK 14.0.1408 from 14.07.2004 Virus news: www.guardianproducts.com
_______________________________________________ the OrchidGuide Digest (OGD) [EMAIL PROTECTED] http://lists.orchidguide.com/mailman/listinfo/orchids
