Growers Network was created as a resource for adults in the cannabis industry.

Please verify your age to enter.

Supplementing LED light with CMH/HPS

I thought i’d start a new thread to discuss this.

I’m in the process of turning one of my rooms over and next round i want to throw up some new LED’s. I also want to supplement with CMH/HPS. i assume this will be in a checkerboard fashion but i’m open for opinion on good ways to go about this.

the room is 18’ x 23’ currently with 15 HPS in a 3x5 grid.

If i go standard checkerboard with 1 LED over a 4x4 followed by a CMH/HPS followed by an LED, etc… is that enough? the goal is to suppliment my LED light with the penetration and spectrum of a traditional(ish) type bulb. now common sense tells me that while the plants directly under the lights will get some of the lights from adjacent fixtures it won’t be the sum of the 2. especially under the CMH/HPS. the LED light will travel directly down and not so much “over” near as much as the CMH/HPS light will. not sure if that’s a statement or a question.

any input on the correct way to do this appreciated.

thanks in advance.


Hi Tom,

your idea is pretty reasonable since you can combine the advantages of both worlds:

  • UV and Infrared light from CMH/HPS
  • Efficiency and controllability from LED

But to do it properly a lighting plan would be nessecary and also walls have to be considered since reflected lights could be used to opimize the mixing.

  • given your 18’ x 23’ we talk about a 37m² room (sorry for the m² but I am not used to ’ yet :wink: )
  • I assume that we talk about 15 x 1,000W HPS = average of 550 - 700 µmol/m²/s within your room

So what would we do:

We would combine

  • Cycloptics CMH Thats the best choice if you want efficiency and homogeneity…

with our

  • HASHCROPTER. Due to its adjustable arms and 4 light sources it will be quiete easy to combine both technologies. Furthermore it is dimmable and spectral tunable!

Third step would be to optimize your walls in oder to increase efficiency and also optimize homogeneity too.

What do you think about our approach. If your are interested we could offer you such a solution based on a simulation of the outcome.

feel free to get back to me.






in a perfect world i’d run right out and buy a new system.

in my world, i’ll be using existing lights along with a demo batch of LED’s from a local manufacturer.

right now i’m curious as to the nuts and bolts and general how-to bulletpoints of my extremely myopic scenario.

are the cycloptics something you sell or just a general go-to for the industry? i’ve not looked into these before.


No we do not sell Cycloptics! But we recomend them because those guys are the only CMH supplier (we know) with a well designed reflector approach…

By the way have you checked out our HASHCROPTER? What do you think?


THB i’m too ignorant to say much more than “it looks cool” lol. i’ve only had time to pull up the page and glaze over it briefly.


I can help. DM me.

You’ll definitely want a game plan for supplementation. A few things to consider:

  1. The idea that “LEDs don’t penetrate” is a common misconception. A well designed, full spectrum LED deployed properly can provide excellent penetration on par with HID lighting. But of course all LEDs are not created equal.

  2. LEDs aren’t as of yet very good at producing UV light, especially in the long term. HPS has very little UV, and CMH produces less UV than you might think. At this point, fluorescent seems to be the most practical UV source, so if that’s important to you then you might want to contact someone who specializes in that, such as Solacure.

  3. LEDs also produce very little radiant heat. If you’re in a cooler climate you might want to use HID lighting for its ability to heat the plant canopy directly. If you’re in a hot environment you would probably want to avoid this.

If you have luminaire files for the HID and LED lights you intend to use we could generate a lighting plan customized to your facility. If you don’t have these files we could probably use the product specs to get you a pretty close idea.


DM sent.

so is the only benefit of checkerboarding increased spectrum?


Broadening your spectrum can be one benefit. Others include reduced startup cost and additional heat for cooler climates. They key is knowing your specific environment and what you’re trying to achieve.


we just want better product and cheaper electric bills. environment is controllable. we grow decent enough weed, just want to do it better and cheaper. the boss man is afraid of going straight LED. he “knows a guy that knows a guy that runs a checkerboard and he grows pretty good stuff”. i’m pushing the LED’s and having to meet him halfway with supplementing at this point in time until the LED’s have proven themselves to work.


Hey I thought I might chip in my two cents here since I often deploy these LED/CMH light combinations into lighting arrays that I design. For CMH, I love the RA Reflector from Sunlight Supply. Like the Cycloptics that @cschubert recommended (great choice, BTW), the RA has a vertically-hung bulb, and they are fairly inexpensive. I found one on Growers House in case you wanted to check it out. I often integrate them into my study formats as well because they run cooler than HPS but consistently produce deep-penetrating light; I thus get consistent results. Check out my Harvest Gold Study to see some of the results I got off one light in a 3x3. I almost always pull at least one pound per each 315 watt light.

I like to mix these lights with a variety of LED’s. I like the broad spectrum LED’s produce and the tunability of many fixtures. I have tested many brands. I like the combo of CMH/LED because I get light penetration, broad spectrum, and lower energy bills from light/HVAC power consumption. On another LED note, I have recently started The GrowFlux Bloom Study and will have results coming soon. Stay tuned!

I’m always available to chat about LED’s and CMH lights; just reach out! :grinning:


Hi @Growernick,

I am sorry but I would not recommend the RA reflectors from Sunlight Supply since the efficiency and also the radiation patterns are not good enought. Those reflectors are just designed to be as cheap as possible. So to save USD200 of investment upfront is not worth it :wink:

Regarding the combination of CMH and LED we would recommend to supplement with a tunable blue and red channel in a 1:3 ratio.




Is there a more effective reflector you can recommend? Why do you feel these ones are so cheap?
What concerns you about the radiation patterns specifically?
My research has been toward LEDs lately so im ignorant to the majority of HID systems.


Hey @cschubert,

The RA may be may be cheap, I concede this fact, but I pull well over a pound of finished, dried, trimmed, and cured flower every time with each of these lights and an additional 1/4 pound of trim to turn into concentrate. Not too shabby for 315 watts, especially when you consider existing industry metrics for success. I like the light they produce and the vertically-hung bulb. The light patterns seem to be quite adequate for consistent crops. Granted, I integrate the CMH with LED’s to get a nice, broad spectrum so the plant response can be influenced by the LED light; but even when I use RA Reflectors as a standalone light source, I pull weight.

I’d be interested in the HashCropter thought, compared against other LED’s I’ve used.


HI @bryan.eden, Hi @Growernick,

Don’t get me wrong. I am pretty sure that Sunlight supply reflector will work! But as I said I wouldn’t buy one of those as long as there are solutions like Cycloptics reflectors out there… The difference between both is that the cycloptic one has been optically designed in order to minimize losses (parabolic design = “one bounce and out”) furthermore they do not only focuse on a horizontal optimization but also on a vertical optimization of illunmiation in combination with the optimization of the walls of the phyto chambers… Summarized, the cycloptic guys know what they do!!!

So what i tried to say is that a cycloptic reflector allways will outperform a RA in terms of efficiency and effectivity if used properly.

RA is cheap because manufacturing is much cheaper compared to cycloptics reflectors. And also the cost of development of a cycloptic reflector is much higher… But anyway I am not here to recommend products of our competitors :wink:

@Growernick: If you want to test a HashCropter I will send one over to you!




It is not a feeling its expierience because we have designed quite a few reflectors by ourself :wink: But maybe I am a pedant since our main business is still equiping research institutes and those guys are pedantic too. :wink:


Yes an optimized spectrum is the main benefit! But only if it is done properly otherwise you will end up with areas with different spectral compositions and that can be dangerous since your product quantity and quality will vary much.