8 x 54 = really happy plants
4 x 54 = happy plants

They make plenty of heat, as watts are watts for the most part. They just feel cooler to the touch as their heat is spread over more surface area than a single HID. Ventilation will be needed and must be adequate. Somewhere between 200-400 cfm in 2x4x6 area if intake air is 70-75•F.

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Don't incarcerate self sufficient sick people. I grow cannabis for ulcerative colitis and to relax. http://www.rollitup.org/grow-journal...ganic-s-c.html

Great advise!!!+rep

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http://www.rollitup.org/indoor-growi...icy-fruit.html

The real problem is that at 5-8 weeks, your plants will probably be too tall for this lamp to reach the lower part of the canopy. Consider using t5 strip lights as supplements.

I have a little over seventeen thousand lumens in my closet grow. Two, four foot, two tube fluorescents and four cfl's. My golfing partner is using a t5ho with twenty thousand lumens. His grow is a week ahead of mine. My plants just turned a week old and I'm hoping the t5ho light I ordered comes in today because his plants at two weeks old are amazing. He is using a four tube four foot fixture. I researched the lights and a t5ho puts out more lumens than a metal halide 400w. I have eighteen plants in a space that is only fourteen inches wide. My light schedule is 12/12 right from the start. I'm trying to cut down on the veg state and basically have one main cola on each plant. I plan on keeping the four cfl's for extra light during flowering, however the t5 alone seems to be working fine for him. Hope that helps.

8 T5's is perfect, its what I use and flowering with the orange ones is even better .