Ceramic Metal Halide (CMH)

[Koondense]

I'm thinking of doing it for some years but never did.
Found some nice prices for the lumatek 315 cmh fixture, but somehow I feel I would prefer a vertical position for the cmh.
The goal is a vertical 315cmh(3100K) in the center with 4 led cobs on the sides, 95w each(dimmable).
Maybe next winter

 

[FletchF.Fletch]

Hortilux 315w CMH flanked by 2 Enjoyield uv/red LEDs.

Barney's Lemon Tree just finished under that combo.

 

[FletchF.Fletch]

This is under HPS and LED.

 

[coxnox]

150(5")x75(2.5")cm with 2x315w philips cmh:

 

[snakedope]

I've been wondering if anyone is doing CMH and LED hybrid grows? I've been running LED for a while now and when I was running COB's I was doing pretty well, but I've moved to the flat panel lighting and there's just something missing. The buds are good, the yields are good, and the smell is good, but it's not great and who doesn't want great? I've not run CMH before but have done a hybrid HPS/LED run out of necessity and lack of supplies over covid which turned out very well. The 250 HPS seemed to fill out the aspects the leds missed, like smell and added temps in winter. I'd imagine a CMH would do this even better, but haven't seen any grows with this yet. I don't want to give up on LEDs, I think there is a lot of potential, but the grass is always greener, or stickier, on the other side right?

One can only wonder ...

 

[Brother Nature]

It's always worth a shot, CMH is the only thing I've not had experience with yet. Most of the growers I admire on here tend to grow with CMH and it would help with adding heat in the winter here. We're in the midst of summer here right now though so I'd have to drastically change my setup and I just don't have the time for it currently. Something like Fletch's setup above looks ideal, one 315 to replace one of my 2 bar LED's leaves me with only 5w less, more canopy penetration, more UV and a little more heating. Always prefer to learn by experience..

 

[zachrockbadenof]

last few grows have been in a 4x3.5ft tent with '2' 315's and phillip bulbs - i'm not impressed , thought we need more light then the 2 cmh's provided - this grow bought a 5x5ft tent with a mars fce8000 set at about 70pct - 33days into 12/12 , and gotta say not impressed with the bud growth - i would say the nodes are closer and not as much stretch, but impressed.... noooo

previous to growing with cmh's, we had a grow room with 4x1000 mh/hps switchable's , and had some truly amazing grows - i'm probably in the minority , but to me cmh/led can't hold a candle to mh/hps...

 

[coxnox]

last few grows have been in a 4x3.5ft tent with '2' 315's and phillip bulbs - i'm not impressed , thought we need more light then the 2 cmh's provided - this grow bought a 5x5ft tent with a mars fce8000 set at about 70pct - 33days into 12/12 , and gotta say not impressed with the bud growth - i would say the nodes are closer and not as much stretch, but impressed.... noooo

previous to growing with cmh's, we had a grow room with 4x1000 mh/hps switchable's , and had some truly amazing grows - i'm probably in the minority , but to me cmh/led can't hold a candle to mh/hps...

too big space for 2x315....i have 2.5x5 with 2x315, it's juste perfect ^^

 

[zachrockbadenof]

too big space for 2x315....i have 2.5x5 with 2x315, it's juste perfect ^^

View attachment 18799272

nice grow - everyone i talk to , as u have said is that 2 315's was enough light - maybe coming from 1000watters turned me off as bud size and resin was lacking... now onto led's, and i think the bud's are smaller, and less resin at 40days then they were under the cmh's...

if i could i'd go back to the 1000watters, but in a tent its impossible... tooooo much heat...

 

[coxnox]

it's not so nice, i will not get yield i usually have, but because it's from seeds and because i get cold nights since 1months....but usually in this tent(5x2.5) i can get from 600 to 800gr of weed, and they look better than under hps(more compact, more resin....but also more leaf).

 

[hillbil]

Still sometimes run an old 250 Retrofit 4000k as an UV supplement to white and white/red LEDs. Still have several NIB bulbs and a couple 400 watt also.

 

[Kimes]

Any real difference between 3100K and 4200K seed to harvest? Or does it matter so much..??

 

[coxnox]

3100 do both good, grow and Bloom why try thé 4k ?

 

[k-s-p]

I used the 4000K retro whites for veg and flower and really liked the end results. I never tried the 3200K. Many people said the 4000K gave better terpene and resin results, albeit with somewhat less yield and maybe more leaf. I was happy enough with the 4000K that I never tried the 3200K. I'm now using the Philips Master green in 3100 and honestly I want to try the 4200K.

I may be off in the xxxxK numbers a little but you get the idea.

 

[Kimes]

@coxnox & @k-s-p Many thanks for feedback. Just was not sure if it mattered, I have a 3XXXK bulb now and it seems peachy so far for my purposes..

 

[k-s-p]

@coxnox & @k-s-p Many thanks for feedback. Just was not sure if it mattered, I have a 3XXXK bulb now and it seems peachy so far for my purposes..

Glad to share what little I know. To be clear, I don't have any issues with the 3100K bulb I am using now, it's doing fine. I only want to try the 4200K next to see if I like it better.

 

[Corpselover Fat]

Glad to share what little I know. To be clear, I don't have any issues with the 3100K bulb I am using now, it's doing fine. I only want to try the 4200K next to see if I like it better.

I doubt there is a big difference. Slightly more compact plants. Interesting experiment anyway. Will you be using the same plants and grow style?

 

[Doc50holliday]

Glad to see there is some recent discussions going on with CMH.

I'm very intrigued about CMH 4200K spectrum and don't see a ton of information on it to be honest.

I keep hearing people say that it's a Veg light (why would you want more blue in flower?) but it appears to have way more red and deep red as well..?

To me this light spectrum on the 4200K appears to be closest to the Sun's light spectrum. Perhaps I'm misinterpreting the graph, anyone have any thoughts on this?

 

[Doc50holliday]

Grown under HPS & CMH

 

[gmanwho]

About 2yrs ago i wanted to build this, and it finally has become a reality. my 2nd flower room at a new location.

Freshly built unistrut / c-channel 11ft x 12ft light mover with 6 kingbrite cs650 watt 3 channel leds. 3 independent led channels , fullspec, uv, far red. meanwell ballasts,lm301h, then i think lg uv or red diodes, i forget atm.

then 9 315w phillips master color 4200k vert bulbs. Cmh wired for 2 independent or combined light / lantern patterns. one circuit wired like a " number 5 on a dice". the other is a 4 pointed diamond, or a square turned 90 degrees.

Last spot i ran these cmh setup in between de 1000's and never ran wattage above 750w. great results. so i wanted to try them with leds

2 points: with being able to control cmh at 45% (4lights) or 55% (5lights) or 100% (all 9 lights), then dimm the leds to match wanted light ppfd/dli. Hoping to get the point where the cmh will add extra heat to the room to prevent dehumidifier from cycling during lights on. Allowing the high efficiency AC to run a little harder therefore pulling more hummidty from the room. (less energy then running quest dehumidifier)

Or 2, adding heat to the room during the winter.

Well, all in a theory, maybe, only one way to find out


pic at cmh start up
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