Oncidium Parquet ‘Uptown Girl’ pleating and doing badly overall

[estación seca]

Brightness of light varies dramatically with latitude.

I was in Frankfurt (50 degrees North) once at midsummer. At the botanical garden they had multiple high intensity sodium lights focused through the greenhouse glass onto some of their Ariocarpus and Ferocactus cacti. The lights were inches from the glass on the outside and the plants were inches from the glass on the inside. The curators told me without this the plants would stretch and etiolate. In the lower desert in Arizona these species don't etiolate even with only a half day's sun.

This is one of the reasons I'm in awe of early European and English orchid growers from the 1800s. They were able to grow and flower high-light orchids under what I consider low light conditions, without artificial lighting.