I can germinate them and grow healthy plants the first season, then I let the soil dry out when the leaves yellow, and keep them warm and dry until winter. I'm in Portland, Oregon, and I leave the potted bulbs out in the cold greenhouse, but I don't let them get colder than 40F. In spring, I give them a good watering, since I read that triggers their spring growth. But it doesn't work. They won't break dormancy, even though the bulbs are sound. Any idea what I'm doing wrong? Too cold maybe? Thanks.