Upon re-reading this part of my statement, it is to general of a statement. I was think about small perlite.
Though on a quick read of Ray’s Semi-Hydroponics Basic he writes “The medium is another key component of the culture technique; it must be inert so it won't decompose, fairly uniform in particle size so it provides lots of free air space, and must provide good capillary (wicking) action to keep it uniformly moist. “
I would say the uniform particle size helps in providing good capillary (wicking) action and capturing evaporation not free airspace.
A better statement would have been to say uniform *small* particle size helps in providing good capillary (wicking) action and capturing evaporation not free airspace. The larger the uniform particle size the less capillary (wicking) action and the more free airspace. There other particle properties that come into play in wicking: Think a pot of soil or peat with the bottom in water, then think a pot of marbles with the bottom in water.
Mark Sullivan
_______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
