Quick question

Will tinfoil work to put on the walls of my closet so the light can reflect off of it?

NO use mylar, the emergency blankets at wal mart in sporting goods. tin foil redirects in a sharp line and can burn a plant.

They say it creates hot spots, I would go with mylar or flat white paint. I use the reflective roofing paint, $30 a gallon at home depot. That paint reflects at 90% or you can go with cheap flat white paint at wallmart for around $10 a gallon.