Question
Hello. I live in Norfolk, Va. and have a mini Cattleya, a red Lady's Slipper, and what I think is a Oncidium on my balcony. It was sold as Cymbidium, but the blooms look like Oncidium. My Oncidium is about 2 feet tall and bloomed very well. It had about 5 flower spikes on it! It only had one when I bought it. They were about 1 1/2" to 2" blooms and were spotted. It has long light green leaves that are kinda sword shaped. It doesn't really have those pseudobulbs like the cat. They are flatter. After it finished blooming, I repotted it. It was spilling over the side of the pot. Well, the roots didn't look too great, so I trimmed the dead ones and changed the mix to a fir bark, perlite, and charcoal mix. I also divided it in half and put each in a 4in. plastic aircone pot that is in a clay pot. There are new roots forming slowly on both. One has a new shoot coming up! But there are small brown spots on the tips of the leaves and on the base of a couple bulbs are an oval shaped dark brown spot. Am I doing things right? Is this a fungus or just salt build-up? Please help me!
Theresa

Answer
Hi Theresa,

From your description, it does sound more like an oncidium rather than cymbidium orchid.

Little brown spots near the tip of oncidium leaves is not unusual, so not much to worry about on that front. Oval dark brown spots near the base of the pseudobulbs may or may not be something to worry about. If they are soft and mushy, that is not good but if they stay firm then they may be okay but should be checked once in a while. Also, if they appear to be getting larger, then it may indicate a fungus infection that will need to be taken care of soon before it spreads and kills the oncidium. If the spots do grow larger, unpot it and remove the infected bulb with a sterile knife or razor blade (I use industrial grade single-edged razor blades to do this operation). Look at the cut to see if you see any brown areas to indicate it is spreading to the next bulb, if it is, remove that bulb also. Keep removing bulbs until you can no longer see any browning. I know doing this can be painful but it is necessary in order to save the plant.

Salt build-up normally shows up as browning of the leaf tips and slowly progresses down the leaf.

Hope this has helped.  Good luck and good growing.

Jim Kawasaki
San Jose, Ca.