Dry-stall vs Horticultural pumice ... was algae and moss in seedling pots
Ken (Wed, 01 Feb 2012 10:30:50 PST)

Thanks Mark,

Is 'Dry-stall' significantly different from Horticultural pumice?  I thought I had hit upon a great thing because it is much cheaper but seems the same as Horticultural pumice I have bought.  I do top with DG (decomposed granite.)

re the moss ... I do keep the seed trays in shade, covered with a humidity dome until the seeds germinate ... then remove the dome and gradually move to a more sunny locale.  The moss and algae didn't seem to take off until after I moved the seedling trays into the sun, which is plentiful albeit low-in-the-sky winter sun.

Anybody?

Thanks,

Ken Blackford
San Diego, CA  USDA zone 10

--- On Wed, 2/1/12, MARK MAZER AND FREDRIKA MAZER

Your problem is that the top surface is not drying out because the
Dry-stall absorbs so much moisture.  Topdress with something  like granite
grit.  Rainwater is probably the source of the moss.