Question
in every book of orchid growing the advice is grow orchid in very open potting media or mounted , while orchids seedling in flask grow in  jelly  like medium without  any openness.
how  the seedling adapt to these condition? thanks and best wishes-cohen

Answer
Hello Cohen,

Yes, just about every book about orchids along with most orchid growers will recommend using an open media to pot orchids.  The basic reason for this is that orchid roots need exposure to air to help convert water and nutrients into food for the orchid plant.  Without air as in media that compacts to form tightly around the roots, the roots will suffocate and die.  

As for seedlings, when the seeds are first sown upon the agar media, the agar is formulated to provide some nutrients and moisture to the developing seeds.  Once those seeds have grown large enough into recognizeable seedlings, they are removed and usually put into community pots that will hold upwards of 30 seedlings.  As the seedlings grow ever larger, they eventually end up in individual pots of their own.  

Hope this helped.  

Jim Kawasaki
San Jose, Ca.