315w cmh spacing

hey yall, I’m making the switch from hps to cmh and was curious to what kind of spacing. In the first section that I’m switching over is a 4x20 space that had 5 1000w hps. I’m replacing with 8-315w cmh. I have the 315s 28” apart from center of each light. Would it be more efficient with less lights spread further apart?

Everything I have read says 3’ on center.

I only have 1 but 3’ between bulbs would be great.

I was going off a 3x3 footprint with some over lap. My main concern is head, I under estimated how much heat they put off.

Jakkar said:

I was going off a 3x3 footprint with some over lap. My main concern is head, I under estimated how much heat they put off.

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I think the open vertical reflector with the Phillips 3100k I have is about as hot as my air cooled glass enclosed 600 super hps.

I needed an extra 6” exhaust when I installed it in my flower room. Ventilation is key.

Also run circulation fans between the lamps and canopy to blow off the radiant heat.

From the hand test it felt to be about the same as my cooltube 1000s. I was hoping they would be cooler than that. I’m running a horizontal reflector with Phillips 3100k. I might knock 1 light out and run them at 32” bulb to bulb.

Okay first I will say that I don’t think 8 315s match up to 5 1ks as far as yield goes (I guess depends on your yield from hps) and I also don’t think think they cover a 4 foot width either(unless part of your room is walkway). You room is just ackward shape/size for 315s to cover it all properly.
Your watts have been cut back so much That if it was me and I could afford it and cool it I’d use 10 in that space hung side by side at 4 foot centers with the bulbs orientation running the same as long wall of room. closer to the walls than center(walls must be reflective for that to work right, Mylar is cheap).
That being said cmh is great I love it but I don’t buy the hype that you can run them so soft (far apart).

Disclaimer: I run way too much light per sq ft according to every hydro shop worker and friend I know. Its bullshit tho it’s like saying 2 600s is enough for a 4x8, but look at yields grown that way.

I average 6.65lb in that area with 5 1000s, I’m hoping i can stay near that yield with the 8 315s. I have the lights staggered to cover width and with the overlap there’s just a little dead space using a 3x3 foot print. I was just reading some other forums about people using 8 315s covering like a 8x20 room and pulling big weight and that’s what made me question what I have going in

Yeah staggering would prob work I was hoping to do 8 in a 7x11 room cooling it is what I’m worried about I can’t get a solid figure for cooling 8 of them with a mini split. I could start with 6 and see, if you see people say they are getting that kinda coverage but that’s as low as I’ll go because I did the math on that size and wattage u said about 8x20 and was 15.75 watts per sq ft. I just can’t see how that lights up that whole space. Would be nice tho, I hope I’m wrong.

I hope I can get to your guy's level someday lol.

I got all the lights up last night and was able to test them out. Seems like my coverage is pretty damn perfect. Room temps before lights were turned on was 79f and 81f half hour after lights were on. My temps were around 83-84 with the 1000s. If all goes well I will be replacing my other 5 on the other side of the room with 10 315s, it’s a 24x4 area.

That’s great, after thinking about it your only trying to light 3 more sq ft than I am it just a different shape so I hope the 8 work out for ya. The real question is what are you using for cooling in that area? I wanna run 8 in my area but don’t have the mini split in yet and not looking good til spring to get it in. I think for now I’ll do combo with hps and my de 630 so can air cool them (can’t reccomend anyone buying de630 but I already got em, they bright af don’t get me wrong but bulbs are junk).

This room overall is 10x24. The side the door is on is the side I put the cmh and the other side is 4x24 with 5 cooltube 1000s. I have a co2 burner in the middle of the room that produces quite a bit of heat. I also have 2 humidifiers that mist cooler water. I have 4 smaller 8” carbon filters and fans that are strapped to the ceiling to help pull hot air out. For a/c I’m using a 48000btu mini split. Also have 8-10 wall mounted fans.

How many btu would you think it takes to cool 8x315 in 7x11x11?

I think there’s a few factors that go in to play when choosing an a/c. Are you in a basement that’s already kind of cool or a garage that’s well insulated? What else in the room generates heat and how much? Are you pulling any in or out? But if I had to take a random guess I would think a 24000 Would be enough. Might be even too much but it’s always better to have more than you need.

If your looking for yields
DE1000s 4x4’ or 48x48” or 16sqt.

If I had to ceiling height I would be running DE1000s. Having 7’ ceilings is a buzz kill.

Jakkar said:

If I had to ceiling height I would be running DE1000s. Having 7’ ceilings is a buzz kill.

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7’ Is hard to work with, I got 8’

BigHornBuds said:

If your looking for yields
DE1000s View attachment 42019964x4’ or 48x48” or 16sqt.

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I have thought about 2 or 3 DE 1000 but not sure how would space them in 7x11x11. What’s your avg per fixture? I see people say they get 2 or more per de but is that dialed in pro’s or the common person?

BigHornBuds said:

If your looking for yields
DE1000s View attachment 42019964x4’ or 48x48” or 16sqt.

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Growing vertical with 2 stacked 315W CMH lamps on screens in my 4 x 4 increases my footprint from 16 sqft, to 33.75 sqft.
My screens are 44" x 22" so that 6.75 sqft each.
Here are the 5 plants in the tent. This pic was taken early in veg.


Here they are in early veg.


Just over two months later


Here are a couple of the individual screens in flower.


I pulled 26.5 zips off this grow.


I have changed my screens from plastic to Stainless Steel. The plastic screens would pull out toward the light where the stainless is rigid.
GR

My flowering space is 4x16 I got 4 of them.
I avg 3 a light .
If you can maintain a good environment 2 a light isn’t to hard. Do 3 + you’ll need to be on your A game .
4 is possible with the right genetics, I would love to see what I could to with 100 of them and 12’ ceilings .
@CalmedDown