Distance between HID and Plant

Hi,
 
What distance is needed between a 150W MH and the plants, to fully cover the plants 1 square meter (1m²).
 
Thanks
 
 
Chili-Fan

With a 150 watt mh you can get pretty close. I generally put my hand under the lights over the top of the plant when figuring out where the light needs to be and adjust accordingly. If you can feel the heat on the top of your hand an it's uncomfortable raise it. There's a plethora of info on lighting. Nothing is really set in stone.