Question
What could cause the blooms to die as they open up. I have 5 stems of blooms, and as they begin to open up, they turn yellow or pink and drop off. This happened to my large orchid last year also.
Thanks in advance
Bruce

Answer
Bruce, there are three main causes for bud abortion: 1) dry atmosphere; 2) temperature, 3) poor root condition.  To illustrate the first point, I recently had this happen where I moved an orchid from my greenhouse to a windowsill in the house.  The greenhouse is far more humid and I lost all of the buds on each of four spikes. Temperature can cause bud drop if there is a sudden drop in temperature-- even for a short duration. The third condition is more subtle and might occur if this plant has not been repotted since last bloom.  When the potting mix breaks down, roots may rot due to lack of air penetration of the potting mix and/or water retention by the potting mix.  These reasons apply to most types of orchids. If the latter reason applies and you have a phalaenopsis orchid, you should repot it as soon as the buds or blooms are finished.  With other types of orchids repot when new growth appears.