| I don't have a greenhouse, but it seems I have heard that propane heat is not a good choice? I'm sure others will chime in soon.
In regards to your temperature question - phals will survive with no problem in that temp range, but they will not change much until you warm it up some. Another five degrees would be much better. Maximum growth of phals actually occurs even warmer - 80's. Commercial growers keep their phals in the 80's (even high 80's or low 90's) to maximize growth - at least that is what I read. My phals do the majority of their growing during the warm months - so it seems to hold true for the home grower. One winter I kept them on the cool side - low 60's - and they essentially turned into "plastic" plants until spring. Good luck! mike |