They are supposed to be Fall bloomers, but there are no guarantees. Things potentially seem to be more consistent under lights with some species but who knows?
But if you are growing with the sunny weather as your light source, it would seem to me that Mother Nature can fool with, or adjust, a plants internal clock.
You have some plants that are fall bloomers, others are spring bloomers in their native habitats. But I have run into situations with Southern Hemisphere plants where they can be more prone to bloom slightly out of season.
I think of Bulbophyllum Elizabeth Anne. She always blooms in October. But once every few years I have flowers the last week of September. Even once on into November. But 90% of the time it is October.
Or I recall too that Cattleya bowringiana always blooms for me from mid September to mid October. That was true in NYC, Fort Myers and Michigan. A shift from September to October was probably sunlight related. If the light is proper when bowringiana forms buds, it blooms in September. If you run into less light, unusual cloudy weather at bud formation, it could be pushed back a few weeks into October. However, one year in Florida I did experience several small growths that developed and bloomed in February!! That is totally out of character for bowringiana!
But my point is, orchids do not read the book, they can bloom out of season once in a while.
