Leaf Yellowing
 

Hi all - I am beginner grower in Long Island City, NY. I have several phalaenopisis which are OK. I also have this orchid which I believe is a Dendrobium? It has tiny flowers that are fragrant. I can't figure out where it wants to be. Right now it is in my bathroom in an eastern facing window. Am I overwatering? Under? Too much sun? Too cold? Help.
I recently repotted it but the yellowing was prior to the repotting.

Welcome to the Orchid Board!

Without a tag it's hard to be specific. There are many different kinds of Dendrobiums with different growing requirements.

It looks like it might be Den. kingianum or a hybrid with that. These like plenty of air at the roots, lots of water when making new growth, and less water in winter - but not no water in winter. They need cool nights in the 55 F / 12C range to flower well.

I suspect the yellow leaf got too close to the window and has cold damage. What are your growing temperatures? How are you watering?

I either water in my shower or I soak the entire mixture every week or so in the sink and then drain. Room is in the 60's now - in the summer it gets fairly hot in the morning. I will move away from the window and put back on the floor. I had put in the window because I had read they need to be cold to flower.

Don't forget that orchids, like all other plants, drop their older leaves as they grow fresh ones. Dendrobiums drop lower leaves quite naturally as canes progress so don't be too worried.