Required CMH Wattage Per Square Foot?

Hello everyone, I was just curious if anyone around RIU knew how many watts of CMH lighting per square foot is ideal? I am starting up a new, quite small vegging tent and am curious if a single 315w CMH fixture will be adequate. The tent size is 2ft x 4ft x 5 ft tall. Appreciate any and all input everyone, happy growing!
*EDIT* Meant to add, there will only be two plants in this tent.

From what I've seen of the 315 units the reflector has a rather small footprint so you'd probably be a little short of light out on the 4ft sides. With that short a tent you will need to train well or go with a ScroG setup to keep the canopy low and flat.

You might want a couple of LED strips or other lighting to fill in the long edges or even better a light mover to get the CMH to cover it all. I got a Light Rail about 3 years ago and love it. They aren't cheap but save tons of power over running a 2nd light.

If all you're going to do in that tent is veg and can move the plants around to share the sweet spot then the 315 should be plenty on it's own.

Yes I'm only using this tent to get the two plants ready for the light schedule flip to 12/12, and yes the heigth is very concerning too me, but because they won't be doing their full 'stretch' in this tent I am hoping that this won't be a problem. I appreciate the reply a bunch OldMedUser!!! I about forgot to mention, I am getting a CMH fixture with the attatchment that allows it to be aircooled. I am hoping that this will help if the plants get too tall, although I know cooling a CMH bulb does affect color spectrum. Right now, the height is the issue that has me sweating haha. But worst case scenario, they'll just have to go back into the big flowering tent sooner than later.

I was told by the guys in the 315 lec thread that 2x 315s will flower a 3x6 foot print. So 3x3 for each light . Should be a little bigger for veg I assume?

Best place to ask this question is the 315 lec thread. They gave me a lot of help, answering similar questions as you have.

Best of luck with it

Yeah about 35 watts per sqft is pretty common for CMH. 3x3 area with a 315. 4x4 area with 630 watts. 1000 watter can do about 5.5 x 5.5 feet

Logan Burke said:

I am starting up a new, quite small vegging tent

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for veg, a 315 will do a 2x4 fine. i'd get the 4200K bulb for a veg only setup, not the 3100K

Really appreciate the information everyone, I've been curious about LEC's for years now and I'm thrilled to get my feet wet finally! I'll be sure to grab the 4200k Rky, thanks!

What about flowering with two 315's in a 11 square foot tent? 57w/sqft to much?

Maybe i should do one 315 and a 150w HPS?

JoeBlow5823 said:

What about flowering with two 315's in a 11 square foot tent? 57w/sqft to much?

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What are the dimensions of the tent? A 315w CMH & 120w LED would be nice.

NukaKola said:

What are the dimensions of the tent? A 315w CMH & 120w LED would be nice.

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40''x40''. Kind of an odd ball size but will fit perfectly where its going. I got a gorilla tent and that was a huge mistake. This will be replacing that tent. No led for me. Might do one 315cmh and one 150hps. But I really wanna try two 315's up nice and high so i get good even light coverage.

JoeBlow5823 said:

40''x40''. Kind of an odd ball size but will fit perfectly where its going. I got a gorilla tent and that was a huge mistake. This will be replacing that tent. No led for me. Might do one 315cmh and one 150hps. But I really wanna try two 315's up nice and high so i get good even light coverage.

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Why was the Gorilla tent a huge mistake?

PadawanWarrior said:

Why was the Gorilla tent a huge mistake?

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5. yes you read that right 5. five. cinco. 555555555. 5 god damn zippers to open the front of it. Plus a bunch of velcro flaps. Its insane. Sure its light PROOF. but its so stupid opening and closing it that I just leave it open.

JoeBlow5823 said:

5. yes you read that right 5. five. cinco. 555555555. 5 god damn zippers to open the front of it. Plus a bunch of velcro flaps. Its insane. Sure its light PROOF. but its so stupid opening and closing it that I just leave it open.

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Crazy. I didn't know that.

PadawanWarrior said:

Crazy. I didn't know that.

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They are definitely the best made tents as far as quality but functionality is SHIT.

JoeBlow5823 said:

5. yes you read that right 5. five. cinco. 555555555. 5 god damn zippers to open the front of it. Plus a bunch of velcro flaps. Its insane. Sure its light PROOF. but its so stupid opening and closing it that I just leave it open.

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I guess I don't have a problem with zippers, I am definitely as lazy as they come and I manage to close my tent. I guess it's a good thing blue jeans only have one zipper... lol

Renfro said:

I guess I don't have a problem with zippers, I am definitely as lazy as they come and I manage to close my tent. I guess it's a good thing blue jeans only have one zipper... lol

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My biggest issue is the middle zipper because you have to re-zip it like a coat every time you put it on. And then all the flaps/velcro that are in your way while your trying to zip the shit up.... All while youve got an exhaust fan running like a raped ape trying to pull the doors into the tent.

JoeBlow5823 said:

My biggest issue is the middle zipper because you have to re-zip it like a coat every time you put it on. And then all the flaps/velcro that are in your way while your trying to zip the shit up.... All while youve got an exhaust fan running like a raped ape trying to pull the doors into the tent.

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Man, the struggle is real. lol

Renfro said:

Man, the struggle is real. lol

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So real.

My 7 year old Growlab has thos3 5 zippers also but the Zippers are straight and top and center have external flaps like the Big Ape Tent, design works and flaps help keep light out of tents. It replacement time is coming.