Karl. I appreciate the opinion, but this has not worked for me. In fact, my failures using "a thin layer of sand" are what led me to investigate the effect of light on germination. I used to sow cactus seed the traditional way. Use a nice inorganic soil mix, sow the seed on the surface, and just cover with grit. I used a layer of silica type grit, just enough so that I couldn't see the seed. I watered and placed the pots under fluorescent lights. The usual result: low and slow germination, or none at all. (One species that wouldn't germinate for me using this procedure was Escobaria minima. Uncovered, seed germination was close to 100%.) I could see where a layer of sand may be useful if sowing the seed outdoors, under intense light. I don't think the resultant seedlings would appreciate the high light levels, though. Not every cactus species needs light for germination. However, I will be looking at the effect of light whenever I sow cactus seed in the future. OK -- back to bulbs. (Does Peniocereus greggii count?) Eugene Zielinski Prescott Valley, AZ > [Original Message] > From: Karl Church <64kkmjr@gmail.com> > To: Pacific Bulb Society <pbs@lists.ibiblio.org> > Date: 6/11/2013 9:13:53 PM > Subject: Re: [pbs] Sandoval at Fresno - Cactus Seed Germination > > Eugene, a light covering of sand (1-2 mm) is considerably different than a > light proof covering of aluminum foil. You might find sand is quite > translucent & provides stability to the small seeds. > Karl > On Jun 11, 2013 8:22 PM, "Eugene Zielinski" <eez55@earthlink.net> wrote: > > > David, and others. > > I realize this is a bit off topic, but I want to share something I learned > > about cactus seed germination, by experiment. The smaller globular cacti, > > such as Mammillaria, Matucana, Lobivia, Trichocereus, etc. require LIGHT > > for germination. Therefore, covering the seed with "a thin layer of sand" > > will almost guarantee erratic germination... > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/