I don't grow many Cymbidiums but I have a few. Years ago, I read about some terrestrial orchid potting mixes and gave one a try. It was equal parts Peat Moss, Pearlite, and Potting Soil

. I added a little bit of large fir bark in the bottom. It's really moisture retentive, and pretty airy. My Bletilla and Ludisia LOVE it!
My C. ensifolium has done very well in this mix for years, but the hybrid, grocery store purchases died -- quickly. I just got a couple new seedlings and really want them to do well. Does anyone have a tried and true medium? What about the fir bark based media? Thanks in advance.