CMh 315 distance

How close to the canopy of my Hindu Kush plant should I have the light???

I like to hang my lights at a height that makes the back of my hand warm, but definitely not uncomfortable after 15 seconds at canopy level.

My 315w CMH is around a foot away from plant top,
got as close as C.8" but got scorching.

As Friedguy said feel it,and watch the plant, maybe start at 2' and slowly down?

Is it a 3x3 tent or a 4x4 tent?

In a 3x3 tent, 12-18" in flower and 18-24" in veg is what a 315w CMH should be at. In a 4x4 though, you need more spread so run it at 18-24". A 315w CMH really wont cut it in a 4x4 though, you'll get pretty small buds.

Getting a lux meter will help. You can figure out the intensity at whatever distance and convert the lux into PPFD. You want 500ppfd max in veg and 600-1000PPFD in flower. 30,000 lux for a 3100k CMH is 507PPFD. 45,000 lux is 765, good for flower.

Thank you.. the plant is in a 15x17x7.5 room.

FirstTimeGrwrLngTmSmkr said:

Thank you.. the plant is in a 15x17x7.5 room.

Click to expand...

Is that feet?

I would make sure the plant is in a corner and you paint the walls white or use panda film, or better yet throw up a $100 vivosun grow tent (they're the best tent in the price range). Having reflective walls will increase your yields substantially (maybe even as high as 50%) and reduce the amount of popcorn bud you get if you only have 1 or 2 lights in a room.

For a 315w cmh, the 3x3' vivosun tent for $100 on amazon is the best option. Don't go any other brand unless you wanna drop a few hundred on a gorilla. A 4x4 tent is just too big for a 315w cmh.