At the Pacific Orchid Exposition last weekend, I saw that Manote Quahphanit from Chiang Mai, Thailand, had Bulbophyllum polliculosum for sale. They were tied to pieces of shade cloth that had been folded to the size of a business card. There was no sphagnum under the pseudobulbs.
I recalled Orchid Board members had some questions about growing this, and nobody here knew much about it:
Bulbophyllum Polliculosum
Bulbophyllum polliculosum
I spoke to Manote at length about growing Bulbophyllum polliculosum.
In summer it needs conditions like most other Bulbos: warm, always moist to wet, bright shade, no direct sun.
But, in winter, it requires to be dry and cold (his words.) He said it should be in the 5C-10C / 40-50 F range at night during the winter, or it will not survive. It drops all its leaves each winter.
He said as fall approaches and nights cool, begin to water less, down to perhaps once a week. Leaves will begin to yellow and drop. From this point it needs the cold weather. He said to mist only every now and then, to keep the pseudobulbs from shriveling too much.
In spring, as it warms up, the plant will begin growing. Do not resume watering until the plant is making new growth. Then give normal summer care.