Black spots on Dendrobium finesterrae leaf?
 

How bad is this? Any suggestions how we should treat it?

How are you guys growing this orchid?

What are the day temperatures?

What are the night temperatures?

How humid is it where it is being grown?

How bright is the light?

Is it getting some air circulation?

How often do you water?

Dendrobium finisterrae is one of those in the section Latouria. It is found growing as an epiphyte in the forests of the Finisterre Mountains of New Guinea and Papua New Guinea.

I couldn't find out the monthly averages of the rainfall and temperatures throughout an entire year, but I was able to find a weekly weather forecast of the area.

Here's the link to the weather forecast of that place.

Finisterre Range Mt Gladstone Weather Forecast (500m)

This should give you a basic idea of how to care for this orchid.

I believe the trees this species grows on has moss growing on it, I'm not sure.

I do know that it is humid in that area - (probably somewhere in the high 70's% to mid 80's% relative humidity).

---------- Post added at 04:57 PM ---------- Previous post was at 04:54 PM ----------

Btw, I think those spots are temperature related. Too cool, maybe.

---------- Post added at 05:02 PM ---------- Previous post was at 04:57 PM ----------

A heads up, that weekly forecast are their winter temperatures. They are located just south of the Earth's equator, so the seasons are flipped.

Our summers are their winters.

Their summer temperatures would probably be a bit higher, (somewhere in the mid to high 80's F during the day, perhaps even pushing 90 F). But the night temperatures for the summer would not be lower than 60 F or 70 F.

---------- Post added at 05:29 PM ---------- Previous post was at 05:02 PM ----------

Oh, and I think the pot might be a bit too big. Try downsizing the pot.

Thanks! We just ordered them online so they were in a bit smaller put, but supposedly it was sized ready for a repot (the root system was quite wild).

We've been growing them indoors under light, I'd say we average 60% humidity and they're getting about 1500-2000 footcandles of light, and our temperature probably ranges between 65 during the night and up to75 during the day (so probably not too far off).

Could it just have been it got a bit too cold in transport? Should we do anything to the leaf?

Ok...not a pot size issue, then.

Not a temperature problem where you grow them either, if what you're saying is accurate.

How long have you had it for and when did it start to develop?

How far above the orchid are the lights?

How's the air circulation?

The humidity is a little lower than what they get in the wild,..

I'd keep an eye on the leaf to see things get worse. Don't remove the leaf. It's not necessary to.

Here it was when we first got it (may 15th, so a little bit more than 2 weeks ago). Don't really see any signs of a problem then.

edit: it was a bit cold when it was delivered (might have hit the mid 50s at night in the truck). I'm just worried it's not some kind of rot or disease we might have to deal with.

Air circulation is pretty good, we run a fan in the room with it to keep it moving around. We can try misting it a bit more (or running our humidifier to bump the humidity up - it's possible it could be too lower there, or at least fluctuating a bit as we open up the apartment).

It's not rot.

If it did go down into the 50's F during transit, then yeah, it probably did get too low for a bit, and may have started to show a few days later, idk.

I recommend a warm mist humidifier, spray misting could add to the problem.

I'd just keep a watch on it to see if it gets worse. I think you can keep the leaf on. These problems usually go away quickly once the problem is solved.

Try not to use water that is too cool either, lukewarm water is better.

Thanks! We'll give that a go. Hopefully we can keep it healthy now that it won't be moving around anymore!

I also love the idea of googling a plants habitat then checking the weather. That's a great way of coming up with how to care for a plant. :)