How big of a growing room for the 11 plant system
 

Dear Ron, How big of a growing room would you need to build for the 11 plant system and how big of a light would you need for optimum growth. Also I am planning on building this room in a pole barn in a northern state what would be the best way to keep it heated and ventilated with fresh air in winter time. Thanks Bud Green

The 11 plant is for people with very small growing areas. If I had a barn I would use the 16 plant size because you would use the same size light for both. A 250 W. or better yet a 400 W.
As for your room. I would build it out of 2' x 4's at the corners and use that Celotex 4' x 8' shiny insulation board to build the walls. I would build it about 6' x 6' x 7' high.
The light will supply heat when it is on and any small heater will be enough when the light is out. If you use a propane or kerosene heater you will also be adding co2 to your room as well but don't burn your barn down.