Expert: Jim Kawasaki - 8/17/2006

Question
Hi,
I bought an Oncidium orchid and one palaenopsis orchid 4 days ago.  

Since I brought them home, the Oncidium flowers started falling and looked dried even though I watered it with fertilizer three days ago.  One of my friend told me that it was because I water the plant from the top of the root rather than put it in water and let the root suck the water.  The leaves of the Oncidium also turned yellowish on the tip and had some brown black spots.  Some leaves turned soft and not firm.  I put the Oncidium in the kitchen with enough indirect bright light.

What should I do to make sure the oncidum will bloom again and remain healthy.

Answer
Hi Eileen,

It would be highly unusual for the Oncidium flowers to dry and fall off in such a short time after you bought it due to watering.  What may have caused this is the presence of some fruits nearby on the kitchen counter.  Are there fruits nearby?  Ripening fruits emit ethylene gas which is fatal to orchid flowers.  For this reason, it is best to keep any fruits at least 10 feet away.  

With just a few orchid plants, placing the pot in water and allowing the water to wick up through the pot is fine.  This will prevent the possibility of getting water on the leaves which can cause some problems, especially if the watering is done in the afternoon or evening.  It is best to water in the morning if at all possible.  

Yellowish leaves is an indication that the leaf may have been slightly over exposed to excessive sunlight.  Brown/black spots on oncidium leaves is not that unusual.  Oncidiums seem to be more susceptible to this type of spotting than most orchids.  

For both the oncidium and phalaenopsis orchid, what you want to provide in their growing area is bright indirect sunlight but oncidiums can withstand slightly more sunlight than the phal.  Temperatures between 60 to 85 F with humidity above 50%.  It is beneficial if there is some light air movement around both, so place them where they can get some air circulation but not close to a heater or a/c vent.  Water them when the potting media becomes barely moist.  What I do to tell when to water is lift the pot and if it feels somewhat light, I water the next morning.  

Hope this has helped.  Good luck and good growing.

Jim Kawasaki
San Jose, Ca.