I've always had good luck with equal parts of perlite, pumice, bark dust and coarse peat moss. Since I can't get the latter any more I'm using a coarser perlite, and fine orchid bark. I hope this works as well. I have observed and had reports from several folks even at higher elevations in this area that Pleione bulbocodioides 'Yunnan' does especially well in the garden, even without any overhead protection. Greig Warner Burnt Bridge Creek Nursery Vancouver, WA (Zone 8, Willamette Valley, Just across the River from Portland, OR) PS If anyone has a reliable source for course peat moss please share with all. I think it is one of the most important sources of "leaf mold", etc in a potting mixes.