Quote Originally Posted by Garden Knowm
you should not put anything black into your grow room.. the last thing you want is something absorbing light.

As far as refelecting light up, it is fine... the plants outside receive more light to their underside than any indoor garden could possibly reflect to the underside of leaves. : )
Well we disagree then is all? I know many people who use the black pond liner and have no problems. I also don't think the leaf will reflect any usable light to the underside of the leaf either. I would be afraid of the internal temperature of the leaf getting to hot. The underside of the leaf contains the stomata. The stomata open and close to regulate the flow of moisture, preventing dehydration. If the temperature gets to high for them to open then there is no Photosynthesis and that means no growth. In older plants that could lead to hermies too.

That my opinion anyway.
Peace