Prosthechea vitellina temperatures
 

I'm thinking about purchasing Prosthechea vitellina because I like the bright flowers. However, it's listed as a cold to cool growing. My summer temps are in the 90s for 2-3 months and my greenhouse frequently hits 100 degrees. Is that too hot for this one? I set the minimum temperature in my greenhouse to 50 for the winter months.

Yep, that's too hot. You could always bring it inside for the hottest months. That's what I do with a Cymbidium I inherited.

Thanks, I think I'll pass on this one then. I find it much easier to just stay with what I'm set up to grow. I always end up regretting any plant I buy that doesn't fit with everything else.

Pure speculation on my part, but I think the temperature tolerance of plants has more to do with nighttime than daytime.

Plants have different chemical processes that go on within them in daylight and nighttime. The rates and efficiencies at which they occur can be effected by temperature.

As Ray brought up, nighttime temperature can be much more important than daytime in determining if a plant will thrive. This one would prefer to stay well below 80F but would tolerate some 90F+ days with enough water, humidity and air movement, but only if nights were almost always below 70F and usually below 60F. It would be perfectly happy in the winter down to 40F.

There are some hybrids with this species that would be much more heat tolerant. Procatavola (Pcv.) Golden Peacock (Bc. Richard Mueller x Psh. vitellia) is probably the most often seen and worth a try for your conditions.

My night time temps for the summer months average right at 70. I have high humidity (average ~70%), water almost daily in the summer, and generally have a good breeze.

I already have a Golden Peacock, and so far it has done well.

Take a look at Kool-Logs. There's a current thread in beginner discussions. They might give you enough cooling to make a difference.

Ok, thanks. I'll check it out.