Distance from canopy.

[muordeeb]

What is the minimum amount of distance that a 600w hps can hang above canopy?

muordeeb Reviewed by muordeeb on 11-19-2007. Distance from canopy. What is the minimum amount of distance that a 600w hps can hang above canopy? Rating: 5

[Dutch Pimp]

The general rule of thumb says: Put your bare hand on the top of the canopy for two or three minutes while the light is on. After this amount of time, if the heat on the back of your hand still feels comfortable, your OK. Around 12 to 18 inches is normal. Cool tubes, or air cooled hoods and light fixtures with glass in them, changes everything, generally for the better.

It helps to have a cool air flow between the top of the plants and the light, with ideal temps between 70-85 degrees.

[muordeeb]

Thanks Dutch. I just purchased a 600w hps lamp, I'm switching over from a 4oow hps. I'm trying to increase yield.

[rimbaegeus]

I've got a 600w EYE Hortilux bulb with one of the 2007 Lumatek ballasts in a Sun Gro air cooled reflector with a glass lens which I've sealed off with duct tape. I've got some 4 inch ducting on the reflector leading out of the grow room to a centrifugal fan(172 CFM), which pulls air from the reflector and sends it to a nearby duct. I have a squirrel cage fan (140 CFM) mounted about 2 feet above the reflector pushing air out of the grow room. My grow area is 4' x 4' with a height of 5.75'. I have nine plants in there and my hood sits at about 8 inches above the canopy. The temperature at the canopy is 75 F and the temp of the growroom ranges between 60 degrees at night to 70 degrees with the lights on.

You gotta go for an air cooled reflector, and invest in a good fan. It's nice to have a 1000W beast hanging above your plants, but if your environment cannot support it, it can be less efficient than something smaller. Since light decreases by the square of the distance, the name of the game is really "how close can you get it?" I know if I don't consider the ventilation costs as part of the lighting costs, I'll skimp on it, and then yields would be low.

[psteve]

a Sun Gro air cooled reflector with a glass lens which I've sealed off with duct tape.

The duct tape is not necessary since you are pulling air through the hoods, not pushing it, and it may actually reduce the effectiveness of your exhaust.