I also have plenty of bulbs grown from seeds obtained from Oron, bulbs grow slowly but they do. None ever bloomed though even after 5 years. The problem is that T. cypria likes to produce sinkers instead of increasing bulb size. So they end up multiplying rather than reaching blooming size. But apart from that they grow without problems, even outside in Austria. The leaves can definitely tolerate light frost. I cultivate nearly all commercually availabale tulip species and all are outside. There is little difference to bulbs grown in a greenhouse with min. temp. of 15°C and plenty of artificial light.
So far I haven't found a method to boost bulb size and prevent sinker formation though I've been experimenting with various substrates, pot sizes and environmental conditions. It's completely random. Also sometimes plants refuse to emerge at all and just form new (and smaller) bulbs deeper in the soil. Why - we just don't know.
My advice is to keep the bulbs in paperbags until they start to form green tips in winter, pot them in a well-draining soil and give them little water until the leaf emerges. Give ample water, light and fertilizer during growth and stop as soon as leaves turn yellow. Remove the bulbs from pot, clean and store warm, dark and dry in a paperbag until next winter.
