[sooxiwei]

I do not have good experience using combo of charcoal with shpagnum moss as I loss some VIP plants to it including my Campanulata...

if you were to compare charcoal to the traditionally used perlite:
-Perlite float easily when you water, causing a mess over time if you mix it with medium like sphagnum moss while charcoal won't
-Size wise, charcoal is more flexible as they come in all sizes while perlite proves too fine for bottom filling(flow of a lot after watering if the bottom of the pot does not touch the ground)
-Perlite absorb water while charcoal don't, but stack up charcoal tends to provide space that keep water from totally flush off, where by those part that expose to air near the surface will dry off faster while those in the middle will still remain wet
-I've seen charcoal in humid condition, white mold/fungus is spotted on those that are on the surface(samething will happens to smashed bricks, with extra cheese smell) when mix with sphagnum moss, not sure if it harms or not, but so far my albomarginata "Cameroon Highland" cutting still yet to settle in it after 2 months