Re: How does light reflected in mirrors affect growing plants?

Hi Marissa!

Sorry we've taken so long to get back to your question, but our system still 
isn't perfect yet. I think our other scientists also had trouble finding any 
information on this topic. Since my Bachelor's degree is in physics, I'll take 
a stab at it. My guess is that, there should be no difference at all between 
direct and reflected light on plant growth. Of course, it depends on how good 
the mirror (or other reflecting medium is). Nothing will reflect 100% of light, 
but a well-polished and clean mirror should do pretty well. A poor or dirty one 
will absorb or scatter some of the light and less will reach the plant. But 
since it is visible light that the plants need for growing, anything that 
reflects say 90-95% of the light should be about as good as direct light. 

Of course, there are other wavelengths of light (infrared and ultraviolet/uv) 
that your eyes can't see, and they aren't relected quite as well as visible in 
a standard mirror. But they don't have much influence on plant growth, aside 
from the fact that more infrared causes the temperature to rise, and some 
plants need more warmth than others too.

I hope this helps, and thanks for your patience!