very good questions missann
I also see sphagnum moss as a miracle worker for sick/ailing or special orchids
one you do not need to plant the Sphagnum moss onto anything you can keep the moss damp at all times not to wet just damp and it will also grow from small chopped up pieces
provided it gets bright light and also kept cool so no direct sun light, as I collect sphagnum moss and the moss is always damp from melting snow and rain.
I harvest sphagnum moss once a year from one place then move onto the next patch of sphagnum moss and once I harvest that I do not do that again for 12 months I find in the right conditions sphagnum moss will grow to about 12 inches or more in a year.
the sphagnum moss we have here grows from a single strand but will continue to shoot even when chopped up.
I have seen sphagnum moss to a length of almost 3 feet long.
I can also grow sphagnum moss in a clear plastic bag for 12 months just with placing the bag in a shaded position and keeping the moss damp in can be kept loose once its tight it will not grow as good or may even stop growing
I hope this helps you
I have just moved this into ( Orchid Potting Mediums ) as Sphagnum moss is used as a Medium as well.