Winter Greenhouse for Cool Growers - Questions

[estación seca]

I quickly lost C. mossiae seedlings that got down to 45 F / 7C.

[Roberta]

Seedlings are certainly more fragile. The Catts that I grow outside are big, husky plants. Anything that gets big in the GH becomes a candidate for moving outside if possible. (I don't buy many seedlings... getting too old to wait for them to grow up)

The other factor - acclimating. The plants that I grow outside have been there for awhile. If I acquire any plant in fall/winter that hasn't been growing under my conditions, it goes into the GH. If it's a candidate for outdoor growing, it moves outside in spring, then gets a full cycle of seasons before it has to deal with winter. ( love plants from SBOE and Andy's... those come to me already acclimated)

[stonedragonfarms]

Roberta is spot on with acclimating; I too follow this practice, for me though it means plants procured in winter & early spring spend a couple months/weeks under lights before transitioning to the greenhouse. Once they've been thorough a summer & autumn in the greenhouse, they're usually set to remain, though there are exceptions [some of the anceps hybrids with Brassavola in their background for example]
Something else to consider, which I have not done in my greenhouse here [but did do when in my greenhouse in the midwest when I lived there], is to tent a bench and use a reptile heating mat in conjunction with humidity trays to create a warmer micro-zone in an alpine house. I did this in that space to maintain a small collection of mini-catts that needed night temps to be 10-15degrees warmer and it worked very well. The heater was on a temperature-controlled plug, which was used in conjunction with a timer--I charted the min-max temps in the greenhouse and then used that data to set the timer--it was a prop tent hack that worked very well [and relatively inexpensively] to add a warm zone to a cold greenhouse.

---------- Post added at 10:30 AM ---------- Previous post was at 10:18 AM ----------

I don't grow many Catts, but Laelia-wise, autumnalis, superbiens, gouldiana, furfuracea & hybrids of any of these are all candidates too [you could probably add albida & speciosa to this list as well--most of the 'Mexican' Laeliae are very temp tolerant, aurea & rubescens perhaps being somewhat the outliers]

[Roberta]

L. Finckeniana (anceps x albida) and L. Wrigleyi (anceps x Gur. bowringiana) ... the latter often seen IDed as Finckeniana, slightly different lip but looks similar - quite bullet-proof.