I agree with Nhu. Mine bloom well, and I have found all Phaedranassas
to be very un-fussy about the potting medium. You might try planting
them deeper, they do not want the bulb exposed. Deep planting tends to
discourage offsetting and therefore the bulb can get large enough to
produce a flower bud. Mine never dry out. The climate here is very
cool and damp, so even without watering there is moisture in the medium
and I water them about once a month in winter.

Diana
Telos