Understanding optimal temperature ranges for orchids?
 

Say an orchid is described as "warm to cold" growing, what does that mean? In the summer it's warm and in the winter it's cold? Not very helpful. Is there a temperature scale for orchids that I don't know about?

It is a very inexact method. What you describe could be correct - warm summers, cold winters. But it also could mean the orchid has a wide range, growing in warm areas and cold areas.

If I really need to know, I try to look up herbarium specimens of the species with location data, then I look up the weather at that location. It's a starting point.

It is a combination of both. Outside of equatorial regions, there are seasonal changes. And, many plants grow over widespread territories, both vertically and horizontally.

Echoing Kim's last comment, many species have a variety of ranges with different conditions. A single population my live in a warm location, while others may be from a colder one.

Okay I understand. Some specimens are found in warmer areas, others in cooler. That makes sense, I didn't even think of that. So how do I know what are considered "warm" temperatures? I would say 80F is warm.

I've never heard of herbarium specimens but I have looked at a site in the past that looks at a wild plant and records the conditions of the location it lives in.

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This might help:

Internet Orchid Species Photo Encyclopedia

Most vendors have the information on their website if they don't describe it with the individual orchids.

Andy's orchids, for instance: Andy's Orchids - Orchid Species - Andy's Plant Key Tag

And Hausermann's: https://www.orchidsbyhausermann.com/care.htm

I subscribe to the Baker and Baker Orchid Culture sheets, currently offered by the Troy Meyers Conservatory. They are not expensive ($1 per sheet, less if you sign up for more than 10) and they offer a wealth of information about many different species. Even if you are talking about a hybrid, you can look at parentage background to get a general idea.

There are free sheets available as samples, so you can see what you are getting.

https://orchidculture.com/

Quite often if it is a hybrid, the warm to cold growing description will be because one parent prefers cooler temps and the other prefers warmer. It should in theory make the hybrid more adaptable.

I also use orchidspecies.com as a reference, and the Baker culture sheets (which are contained in Orchidwiz software, which has paid a license fee to the Troy Meyers conservancy for that... especially handy in the listing of minimum and maximum temperatures for habitat) In the absence of that Baker sheet, I look at elevation and latitude - for the equatorial area, I have found that plants that grow between about 1400 and 2000 meters will take night winter temperature close to freezing, and mostly are not too fussy about warm summers with some shading. There are exceptions of course... but this works for me as a rough indication of what I can get away with. For hybrids, you need to look at the percentages... an Slc that is 1/3 Sophronitis coccinea will be fine close to freezing in winter (if dry) but an Slc that is 5% Sophronitis coccinea not so much if the the rest of it consists of warm growing species.