Mine were planted an inch or so deep in a free draining mix (70% ordinary garden compost with small gravel mixed in).
Give them a good soaking once every 7/10 days. Minimum temp around about 20 celsius.
They are very slow to come through.

They do need quite a bit of heat to get started! Even in our extremely hot climate, they often don't sprout until late May--mine just peeped out. If yours are growing anywhere north of the bottom tier of the continental States, you might want to grow them in a greenhouse. Insufficient heat or growing season length will delay bloom to the second year.

I move mine into the conservatory over the winter and reduce watering to an absolute minimum. They basically stand still until the days lengthen in spring, at which point they start to grow rapidly.
One other point - I was told (so not sure about the absolute truth) that consistently allowing to exposure of temperatures below 20 centigrade (even overnight) during the growing season may impact upon their chances of flowering. I followed this tip and got flowers and lots of offsets too.

I'm sorry, Meanie. Do you mean that you kept them from the cold, or the reverse?

I avoided temps below 20 deg c.
There may have been no truth in it, but I got blooms.

Ah! That makes sense to me now! I wasn't sure what impact it had. : }