I wouldn't dare to keep one in sphagnum either! I just bought an Phal at a major box store (half price, it was done blooming) and when I took it out of the 6" green plastic pot it was in, I found that it had a 3" root ball and was just jammed into the bigger pot with sphagnum and the whole mess was sopping wet after three days at home! Fortunately the roots were still good, so I put it into proper coarse medium with bark, a little sphagnum and some coconut fiber. I'm sure I'd have lost that one if I'd left it in that mess! It is labelled though, Phal Sogo Yukidian, it should have huge white flowers when it blooms again! I'll probably have to wait until next year, but it looks nice and healthy.