I am thinking how my outside conditions translate to yours. Calanthe Kozu can be grown outside here with a mulch. Ditto for the Bletillas. in Fall I simply throw a pile of leaves on top of them. Which would mean that simply any cold spot must be fine, as long as the pot doesn't really freeze through.
When nature warms up, bring the pots into warmer sunnier surrounding.
This is not written in stone.....
