I have poted before on sowing seeds, and one post can be seen here: http://thebulbmaven.typepad.com/the_bulb_maven/2008/12/sowing-seeds.html I think, however, it is worth a recap, since winter is the time that most seed sowing goes on at Telos.
All seed of species native to the western USA is sown in the fall. I used to direct sow the seed into pots, but found a much better way of doing it. All seeds are put in plastic ziplock bags in damp vermiculite, then put in the refrigerator. I usually do this in late October, and definitely want it all done by the end of November, earlier is better. In this way, in just one day I can have all the seed bagged up and refrigerated instead of mixing mountains of potting soil, washing pots and filling them, then carrying them all out to the greenhouses. Seed will vary in the amount of time it takes for them to germinate, so I check the bags weekly and pull any that show any sign of germination. Some Calochortus seed germinates in two to three weeks, other species (especially from high altitude) can take as long as four months, so the actual sowing is spread out over the entire winter. By the end of winter, I discard any bags that haven't shown germination. Usually, if the seed is non-viable, it goes moldy. Above is a bag of Calochortus seeds ready to sow.
Seed of South African species are also sown at the same time of year than the natives, but these seeds need a diurnal swing of at least 10 degrees Fahrenheit. If you refrigerate them, they don't germinate, so these ones are sown directly into the pots in which they will grow. South African Amaryllids, such as Brunsvigia, are sown as soon as the seed is ripe. If I am receiving seed from South Africa, that means as soon as I get it, even though that means the seed is germinating at the 'wrong' time of year as far as our seasons are concerned. It doesn't seem to matter, they do fine, and will grow continuously without going dormant for the first year. Such seed can't be stored, they are like small peas and will even germinate on the plant.
Seed of South American Amaryllid species are also sown when ripe. They are not like the South African seeds, having a papery shell, and can usually be stored for fairly short periods. Up to three months is perfectly safe. These species I also bag in vermiculite and keep at room temperature. There are other ways of germinating these seeds, such as floating them on water, but I don't find I have better results that way. I have also tried folding seeds in damp paper towels, but you really have to keep an eye on them, if you let them go too long the radicle will penetrate the paper towels, and you have a mess on your hands. Other South American species that are winter growers, such as Leucocoryne behave like our native bulbs, and are treated the same way.
As soon as any germination is seen, the seeds are sown in pots or large trays. I live in a valley with high humidity in the winter, not the best conditions for seed survival. It is extremely important to have good air circulation for the developing seedlings, or you can lose the lot to damping off fungus. I have overhead fans in the greenhouses, but, more important, are the fans that blow air directly across the seed flats 24 hours a day. The trays are topped with pumice to keep the surface dry.
Here, at Telos, seed sowing is the major task for early winter, but even for hobbyists it can be very challenging and fun. I lost so many precious batches of seeds early in my career as a bulb grower and still occasionally have failures, usually due to severe weather.