I Think My Gongora Tricolor Froze It's Bulbs Off!!
 

I recently purchased a blooming size Gongora Tricolor mounted on cork bark. A couple days after I placed it in the shade rack we had an unexpected cold snap with night time temps down in the upper forties.
That was a week ago and to today I noticed that three of four of the developing growths have turned brown and some of the leaves are yellowing and a few are crunchy at the tips. When I tested some of the developing leaves they slid right out. There was no obvious sign of any sort of pest.
Being unsure what the problem might be I thought it might be an infection of some sort, so I sprayed the plant down with some liquid copper fungicide.
Anyone have an idea if this is most likely cold damage or are Gongora tolerant of temps in the upper forties?

Thanks for any advice you can give me.

Aaron "Thought He Had This Orchid Thing Figured Out" M

Actually I would have thought that this one would tolerate the upper 40's. What was the wind chill?

I have a galeata that grows even cooler than that and I've had no problems with it. But hopefully someone here can shed some light on whether or not that temperature would affect the bulbs. I really doubt it but I could be wrong.......

I have a Gongora galeata as well and it didn't seem bothered by this past winter's low of 33F. A quick Google search did not return the elevation range of Gongora tricolor but according to the IOSPE it's from Costa Rica.

A while back I derived an equation to roughly estimate the average lowest temperature based on latitude and elevation for latitudes between 23°N and 23°S.

73.43424536 - 0.581386273(latitude) - 0.003052922(elevation) = Avg. Lowest Temperature

We know the latitude of Costa Rica is 10°N so with a little bit of basic algebra we can figure out the elevation at which Gongora tricolor would have to occur in order to experience an average lowest temperature of 47F...

73.43424536 - 0.581386273(10) - 0.003052922(elevation) = 47F
67.6203826 - 0.003052922(elevation) = 47
- 0.003052922(elevation) = 47 - 67.6203826
- 0.003052922(elevation) = -20.6203826
elevation = -20.6203826 / - 0.003052922
elevation ≈ 6,750 ft.

According to the Orchid Culture website, Costa Rica (10°N) experiences a lowest average temperature of 47F at 6250 ft., so the estimate is off by 500 ft., but close enough to give you a general idea.

If we assume that Gongora tricolor has the same maximum elevation as Gongora quinquenervis (1400m to feet = 4 593.17585 ft)

73.43424536 - 0.581386273(10) - 0.003052922(4600) ≈ 53.6F

As a comparison...here's the estimated average lowest temperature for Gongora galeata...

73.43424536 - 0.581386273(17) - 0.003052922(5900) ≈ 45.5F

My galeata had no problem with 33F...(which is one example of the difference between average lowest temp and lowest temp)...then again, it didn't have any new growth at the time. New growth is more susceptible to cold than mature growth. Spring time can be tricky because warm temps, which can encourage new growth, can immediately be followed by cold snaps which can kill new growth.

As you probably already know, cold and wet are dangerous combinations as they can lower the "immune system" of the plant. Cork often has nooks and crannies that can hold water...which is great in summer but not so great during winter. The nooks and crannies can also hide pests and protect them from eradication which is why it's not my mount of choice.

Generally, I try and wait until late spring to mount orchids but if I do mount during winter I use little to no moss...depending on the water requirements of the species. Not sure if there is any moss on your mount but whenever I use moss I try and situate the moss so that it does not come into contact with new growth...or where new growth will be likely to emerge. Ideally, the roots should grow around 1/4" to 1/2" before encountering moss. During summer I'm more lax about this rule.

I also try and make sure that the leaves/pseudobulbs of the new growth does not / will not come into contact with the mount or anything else. New growth is very susceptible to damage so constant contact/rubbing can cause micro tears / abrasions which can open the door for bacterial infection.

When I do have to water during colder temperatures, I water in the morning to give the orchids enough time to dry off before sunset when the temperature drops. Water quality is also a factor. Here in Southern California it rains during the winter...which does not seem to bother my orchids, most of which are mounted. They actually seem to perk up in the rain. Andy of Andy's Orchids once mentioned that water quality can influence the cold tolerance of an orchid.

Generally I try and do some research on the temperature range of an orchid before deciding to give it a try...but occasionally I spontaneously purchase orchids because they are such great deals that if they don't make it then it's no big loss.

Hi Aaron -
My tricolor has been out for the past week, and we've had temps in the 40's (very weird for this time of year), and my plant, knock wood, looks fine. Fungicide was probably a good idea. If it is recently mounted, I would be tempted to remove it and see what's going on underneath.
Very distressing - this is a really stellar Gongora, and spectacularly fragrant.
Good luck - Nancy

Hopefully its ok. Do you have any pics? My guess is that if the plant is ok, you should have a flush of new growth to replace the dead growths. You will probably get more new growths than were killed too, so if you plant is ok, this may have been a blessing in disguise! Of course, that's assuming your plant is ok.

Great post epiphyte78. That was interesting and informative. I didn't know calculations could be done that way in order to get an idea of average temps.

I also didn't know that water quality affected a plants ability to tolerate lower temps as well. It makes sense but not something I had considered before.

Thanks for the info, I will have to keep that in mind for my plants in the future.

I'd unmount the plant and pot it in a netbasket with plenty of Nutricote. If it does die, EGF in Deland has a lot more.