Peter grows in a g/h and the sphag is fairly tightly packed so the watering requirements are very different than what most of us would see in a more open mix, and especially in our home spaces.
I have a few plants in tightly packed sphag and they definitely hold their moisture a LOT longer than any other media set up...even in my very dry, under lights, home growing situation. I lovingly refer to the space as the desert during the winter...warm and low humidity.
I've also bought some phals from Peter in this media set up and where my other phals need watering at least a couple of times a week in a mix that has a decent percentage of sphag in the mix...his set up required only a little drizzle around the outside edges, once a week, to keep the sphag just damp. Of course, I had to switch them all over to a more open mix before going outside in the spring, or, I risked serious root rot because all my phals are exposed to the elements in their summer vacation spots but it's a great set up if your learn how to water w/it and if the watering can be completely controlled.
I would like to learn this method in certain areas as I need to start dominating my watering habits.