I grow a lot of winter-hardy bulbs, such as Trillium and Erythronium, as well as species tulips and narcissus. The technique that works for me is to sow the seed, moisten the mix, then keep at 60F or above for a couple of weeks. This helps the seeds to absorb moisture, which is not so easy to do at 40F, because of surface tension. A longer period of warmth, up to a couple of months, is not harmful. Then comes the cold treatment at around 40F for a few months. But I don't let them get below 25F. When they germinate, I grow them cool, 50 - 60F for a month or so. I found that temps of 70F or above cause high losses. I don't use GA-3 on any bulb seeds. For a discussion of Erythronium germination, see http://www.srgc.org.uk/forum/index.php?topic=197.0 .