I have two Den anosmum keikis and I've found them to like to dry out between watering during colder months. I have it in coarse bark media and I watered it about once a week like Roebrta suggested. Wet + cool tends to spell disaster for many of my warm growing orchids...
I also had new growths start in winter and I killed it by over watering it. Just be careful and let it dry out each time.
During the warmer months, they can't seem to get enough water.