I can't ofer much but I heard that if you pant the walls of a room containing african violets green or blue they grow better. just a rumor.
Aug 14, 2011 Rating
Walls Painted To Reduce Light Intensity by: Melissa
Hi David.
Thanks for your question.
The main reason the walls of greenhouses are painted (usually white washed) is to reduce the light intensity in the greenhouse.
This is done for all kinds of plants not just orchids. Orchids are a very diverse group of plants and very few of them like really really bright direct light. Actually, orchids are classified as "Warm, Intermediate and Cool" depending on what sort of light and temperature requirements they have to survive and thrive.
In many environments the light and the inclosed greenhouse is just too bright and can get too warm so the walls are often painted. This reduces the light intensity. They are often painted white so this still allows for a lot of reflective light.
It is also accomplished these days by using shade cloth which can be purchased with different levels of shading. And some of the plastic green house materials are already opaque to help accomplish the same thing.