to end all this nonsense and confusion, i've actually used mirrors indoors/outdoors and what i have found is that it will create hot spots in lights with high heat.mirrors r ideal for flourescent growers. but the key, is to angle the mirrors so that the light is directed at the plant. the mirror just simply acts as if there was the same light hitting it from a different angle. in experimenting i found that low quality mirrors will decrease lumens directed back at the plant but it won't decrease that much though.when i used it outdoors i had extraordinary results. the plant of course needed twice as much water cause i had four mirrors angled south at the sun. the plant sometimes had no shadow because the mirror made the elusion of the sun surrounding it,the plant grew the best i've ever seen a plant grow. it hada thicker stem,branches,bigger leaves, foliage grew like crazy,it stayed shorter,had a very deep green colour.the plant had 8- 4inch branches at only 5 weeks after germination and the plant was only 10inches tall. Now with all that said i would not recommend anyone doing this outdoors unless u can visit your site twice a week to keep it watered. there is actually alot more u would have to consider, so leave me a message if u want help with this because your plant could see a horrible death if not taken care of like it needs to
and i don't want to here replies challenging what i said if u have never done this