I obtained a mature Brassia orchid as a gift about two months ago. When I first recieved it everything looked fine. It had a healthy spike of flowers and about a month later sent out three others that are now beginning to bloom. It is currently in my bedroom and recieve's shaded light (due to a tree) from a south-west window. The temperature in my room reaches the high seventies. I keep it's pot on a tray of pebbles filled with water to increse the humidity. I've watered it once every week and fertilized it once every four weeks with a 18-18-18 solution. Everything looked fine the first month and a half since recieved it, but about a week ago I noticed three edges of some healthy leaves turning a brownish-yellow. I was certain this wasn't caused by the light because it's not that bright to burn it. I noticed that it was getting a blast from the air-conditioning and I recently moved it from that place. It's now a week later from that time and I've noticed four more of the tips of the leaves are beginning to turn this browish-yellow. What could I be doing wrong? How do I help this or prevent this from occuring again?
What is the condition of the potting soil? Also you want to make that the pot is not sitting in any water in the humdity tray. to make sure set the pot on top of something that sits on top of the gravel. Got a light meter? You should check with Andy's Orchids on the net and see what he recommends as minimum light. Your plant probably needs more light too.
