Question
My husband bought me an oncidium orchid and taking a look at the leaves they have small black spots on them.  There are two psuedopods and they both have leaves with the spots.  One is worse having all the leaves covered in spots and one leaf particularly bad.  The last time I had an oncidium (the chocolate variety) it had larger spots that I cut out of the leaves as well as these small spots.  It took several years, but that plant finally died even with repotting, removal of rotting psuedopods and roots.  I have a phal as well which is in good health and I do not want it to get sick from the new addition.  The plants are in different rooms currently with no plans to put them together until I resolve the black spot issue.  Any help you could give me would be appreciated.

Answer
Hello Laurel,

What a nice husband!  

Oncidiums are prone to having small pin sized black spots on their leaves, usually on the upper half of the leaf with sporadic spots on the lower half.  As long as they are tiny spots, there probably is nothing wrong with it other than they may not look very nice.  Larger spots could indicate a more serious problem.  

You can help minimize the tiny spots by having the oncidium growing where there is good air movement along with temperatures between 50F to 80F, bright morning sunlight with indirect sunlight in the afternoon.  When you water, try to not get any on the leaves, watering from the bottom is one way to do this.  Set the pot in a deep tray or small bucket filled with lukewarm water for 30 to 60 minutes.  Speaking of watering, allow the potting media to become barely moist between waterings, kept too wet and the roots will soon rot.  

Hope this helped answer your questions.  

Jim Kawasaki
San Jose, Ca.