Question

How do mirrors affect the way a plant grows?

Mirror, Mirror on the wall
See how I grow green and tall.
Answer me this question puzzling Nepal
Who is the most beautiful plant of all?

I guess it will depend on what you use the mirrors for. If it is collecting light, then it will help. Often folks growing flowers under lights used aluminum foil or mirrors to gather unused light.

Mylar sheeting is another material used in greenhorses to reflect light.

Different materials in mirrors affect which wavelengths they reflect. some of the ones they may absorb may be ones the plant uses. No reflector can equal the light source.

do mirrors affect the way plants grow

we don't know