Hi,
Need to know if two large 200w cfl bulbs would be provide enough light in a 1.2m square grow room????These bulbs are hanging straight down without reflectors to get the most out of them.
Thanks for any replies

I don't think so.

I'm assuming you room height is 1 meter. I've assumed your bulbs are each 10,000 lumens and they are placed at the top of the room, one foot apart from each other.

You need ideally between 100,000 and 120,000 lux throughout the room. I try to avoid anything less than 75,000 lux.

I don't have direct experience with what you are doing, but I have some simulation software that I use. You can do the same thing in a spreadsheet. The formula you need is: lux at a point = (lumens of light1 / distance to light1^2) + (lumens of light2 / distance to light2^2)

At 1/2 a meter up vertically, you are only getting 20,000 lux in the corners, 30,000 lux on the sides and 68,000 lux in the very middle.