I think I am the most northerly of the respondents and Phals grow well in Calgary. I just put them in the east window as the fall begins to get cool and they set spikes. Because our houses are closed in from October to April, the humidity is low so good moss works well. It retains enough moisture and I water them once every 10 days in the winter...7 days in the summer. I am looking at fine bark for my phal species because they are more particular about too much water. I too have lost a plant or two to crown rot but only in the winter. I get specimen type blooms from this regimen on my hybrids. I am working on the species...all are growing well but it is too soon to talk about blooms yet. I think the critical factor is temperature and the right amount of water.