How close can I hang my lights to the ceiling??

Iam hanging my 400 watt MH horizontally with no reflector. So how close can I hang my 400 watt MH to the top of my ceiling?

If the bulb is about 1 inches away from touching the top of the ceiling is that too close?

I will have proper ventiallation (intake fan and a exhaust fan) and cool air con air coming into the closet.

Hold your hand above it and when it starts to burn then its to close....
Why have you got no reflector ????
What a waste of light energy you should get 1

lpoolfc08 said:

Hold your hand above it and when it starts to burn then its to close....
Why have you got no reflector ????
What a waste of light energy you should get 1

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I was going to either paint the ceiling of my grow closet flat white or line it with reflective mylar, so the top of the ceiling is basicly the reflector.

Get a reflector you can find them cheap and you dont have to worry about a fire... Mylar melts easily.. I tried this once and the mylar fell from the ceiling and when I got home my grow room was 130+ degrees and the mylar had melted itself to the bulb And I thought I was going to pass out from the fumes of the mylar. killed all my plants and nearly burnt my house down. just keep that in mind if you do decide to do it.

nickbbad said:

Get a reflector you can find them cheap and you dont have to worry about a fire... Mylar melts easily.. I tried this once and the mylar fell from the ceiling and when I got home my grow room was 130+ degrees and the mylar had melted itself to the bulb And I thought I was going to pass out from the fumes of the mylar. killed all my plants and nearly burnt my house down. just keep that in mind if you do decide to do it.

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good to know, looks like I will be using flat white paint then. Or I could just get a sheet of alluminum polished metal and screw it to the top of my grow closet ceiling.

I think flat white paint would work best.

Reflectors are shaped to reflect light down onto the plants, in the few square feet below the bulb. If it just reflects off the ceiling most of the light will be lost reflecting off the walls and corners. Remember that the further you make light travel, the less energy it will have by the time it gets to the plants.
Just buy a damn reflector, it's not like they're made of exotic materials and cost the earth, it's only a sheet of ally ffs.

yeah man if you cheap out on a reflector you will pay for it many times over in reduced harvest but whatever right, if your still going to go without then get some foil or one of those aluminum pans to attach to the wall as a shield, but seriously for cheap you can get one of those bat wing reflectors, those work really good and are cheap