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Tell us about your mixed lighting array!

How do you feel about mixing lights? I love a good combo of CMH and LED. I think the combo of deep light penetration and often tunable spectrum produces some amazing results. Have you ever mixed it up with your array? What have you discovered to be the results? Was it worth it, or would you rather stick with standard lighting designs? Why?

We love a good discussion at GNET, so jump right in and share your thoughts on mixed lighting arrays. Let’s mix it up! What have other @mastergrowers, @growopowners and @GrowOpEmployees found when they used mixed lights? Are you curious about what happens when an LED meets HID and they work together to create lighting synergy? This is the place for that conversation!

Do you have mixed feelings about mixing lights? Or are you down with your lights doing some swingin’? Let’s talk mixed lights!


Hi Nick,

To us lighting is not about feelings it is about physics and biology :wink: In the end the technology is just a means to an end. To combine several technology is never a bad idea:

  1. HPS delivers green, yellow and also NIR light at almost no costs
  2. LED can provide blue and red light much more efficient and is far more tunable

In the end you will get something like this:

The hardest part is to make sure that the light of both sources will mix up properly in your grow room…




I cant count how many variations of lighting i have used over the years! From commercial to testing, its been evolving fast finally after this many years!

That said, each has their own, and for their reasons, as for me…

Hate to say it, but i am right along with Nick on mixed lighting. Sorry Nick, you are not alone, lol!

I have spent countless years studying Par/Spectrum/efficiency, and coming down to CMH and LED (CoB), is where i have landed.

Still to date, i have found a wide enough spectrum with CMH only. Led is catching up but I need the full intensity that a CMH offers. Led (I made the switch to CoB) offers more coverage in blues and reds, which helps in late flower for icing.:cowboy_hat_face:


Hi All,

I would love to see some mesurements of the spectrum of such setups taken with a spectrometer… Furthermore I would love to get an idea about the spectral homogeneity of such approaches in the ‘real cannabis world’.



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Hard science! YES.

Back I the olden days late 1980’s a company came out with a greenhouse plastic that forced a hard red shift in the light coming into a greenhouse. Moving plants into these house when ready to induce flowering gave remarkable results. We played with the coverings for years. The problem was labor. Who can afford moving 60,000 square feet of plants from vegetative houses to flowering houses.
The best part was how compact every species we played with was more compact and had higher flower counts. The amount of growth regulators we needed to use was greatly reduced.

A good light meter and tunable lights in my dream come true.

LED’s where just a dream at that time. We had nice HID lighting choices. We could use a digital PAR probe on a QCOMM controller and add supplemental light to keep the crops on target.

The best example was the ability to grow different snapdragons varieties, than competition. We could continue growing the high production types later in the season, than our competition. Snapdragon as a cut flower makes great money at the dark times. We could turn it into a profitable winter crop.

Just by messing with light we could produce snapdragon an a 70 to 80 day rotation when other growers where at 70 to 110 days dependent on season.


Nick you are going to prob get some people angry here but ok here goes.
When i first started growing it was outdoors. We all know its the bees knees. Fast forward ten years(in the 90s) I moved indoors (feds seized the family land) I used what everyone did. HID/HPS. tried and true. To be honest i never liked them. Too dam hot. bills too high etc.
Quite afew years back i started down a rabbit hole. Researching LEDs. Now at this time they were really looked at as not viable yet. I continued on with the old ways.
Last year i switched to full LED set up. Ofcourse its always been a case of JUST HOW MUCH LIGHT IS TOO MUCH. So having a few thousand watts of LED and a Few thousand watts of HIDHPS. i didnt notice any difference. except my bills. To be honest the HPS set ups didnt have any effect.
Mixed spectrums. Man i really dont like it. I feel it can be a little stressful on the plants. There is a thing called too much light. I really dont like going from lets say HID to LED rooms. Prob no issues here just my preference.
I have yet to try a CMH wanted to buy a few this weekend, However genetics took over my wallet. My LEDs have a CRI of 95 thats pretty damn good. its over 2 jewels . very intesnse light. I might be able to release some specs and photos of this( im messaging my business partner) this light is yet unreleased. once it comes out, we feel it will make most cannabis grows pay attention.

my overall feelings. I dont mix. When your light is GOOD enough it will work without added help. i will see about getting some info released to you guys here for eval. This light has been in R&D a few years now so…


Ok i can release a few things here. buckle up.

this is the output chart. as you see its very inpressive.

this is the actuall model. its in production in a few commercial grows. Its blowimg the doors off other LEDs and other lighting systems. Just the shear power output is the reason i dont mix spectrums. i m waiting on the othet specs will post them soon. PLEASE REMEMBER THIS ISNT RELEASED PUBLICALLY YET.


some other angle shots. the bars are removeable and dimable. can use all 8 or just two. this thing rocks


Mixed spectrums are very necessary if you want to maximize the potential of your plants. As for concern about it having adverse effects, we already know through science and through nature, we live in a world of mixed spectrums. What solar effect is it that changes the spectrum of natural daylight? Equinox! Pick one… the spectrums change. Hence in nature determines flowering or fruiting times for all photo driven plants by equatorial shift!

Learning how far you can reasonably stretch those spectrums is where you can really tune your plants profile!:cowboy_hat_face:


I always tried to add the least amount of supplemental light as I could. We would run a constant calculation on would we have a benefit or not on light.

We would target to the amount we want a day compared to natural and just fill in the difference.


I have been hesitant to make the investment in LED’s since most of the results I have seen reported seem to be anecdotal. I use the word anecdotal since most of the “research” I have seen reported has been tests where there has been no reporting on how all the variables have been controlled. That said there was a recent report published in this month’s Cannabis Business Times, “How to Design and Run a Controlled Experiment”, . The purpose of the experiment was to determine if a theory presented back in 2008 regarding the max light utilization that a cannabis plant could use was correct. It was reported in the journal of “Physiology and Molecular Biology of Plants” could use up to 2,000 PPFD of light. The authors concluded that not only could a cannabis plant use the added light, but it was economically feasible with LED light.

It would seem that if their research is correct, LED’s are on a path to completely replace HPS. There would be no way to reach the intensity of the light levels they reported with a HPS without barbecuing the plants. Interestingly they reported that energy consumption was higher than HPS (lots and lots of LED’s to reach the levels they needed) but the added production, 30-40% increase in yield covered the added capital and operating costs.


I understand. I would ask for enough lights to test on cycle yourself. Do your own controlled study.

I am tired of HID lighting and the recurring expenses.

I think if I was to buy any lighting today or any big users of electricity, I want to amp monitor my panel in real time. For 400 amp service, two phase there is a product called Sense.


Sorry i got off on the light issue. while i was going to the doctor i thought about something.

So the spectrums put out by each and every light and manufacturer is different. I feel this could lead to issues causing deformities. I did notice strange anomilies running mixed lighting.

IMHO stick to one spectrums from one manufacturer.

In a perfect world, i would love to have control over all the bands. It would be great to see usb ports on lights. with a app that stores user saved spectrums. based on strain, enviromemt etc. i think this would be great.

Keep it simple, dont over complicate it.


Some of our research collaborators have some unpublished work showing growth deficiencies caused by LED lighting with poor spectral uniformity. I am asking them if we can get a preview so I can post it here. Key takeaway is that spectral uniformity is really important. If you can see multiple colors of light around shadows cast by foliage at the canopy level, the spectral uniformity is most certainly not ideal.

This is the future of horticultural lighting. Except USB ports are not ideal for large deployments of hundreds or thousands of fixtures. For that we developed a high reliability industrial IoT mesh technology called AetherMesh. This makes spectrum control and scheduling accessible from any browser, smartphone, or our API, and further enables sensor based lighting control.


Have a couple growers with Electric Sky LEDs with some MH bulbs intermixed. They’ll experiment with turning them on at end of flower for UVA/UVB coverage.

I’ll just say that sometimes there is a tradeoff between THC (“marketability”) and Terpenes (“Quality”) when using the MH lights.


so build on that. making a data base of spectrums tailored to strains. shareable on a forum type platform

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my current spectral read.

and my ppfd test

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Have the end user light metering caught up with the lightning?

What are my options for monitoring output of the lights in real time


We have something in the works that will give real time canopy level PPFD and spectrum with about 12nm resolution. Production calibration and testing on this product has been taking a while, so these will be ready to order in early 2019.


Does anyone have any thoughts on a format we can use to share spectrum settings/schedules? At the very least the proposed horticulture lighting label has a breakdown of PPF in various bands, however we would need something more like 5-10 bands across 400-700nm to come close to replicating spectrum settings across various platforms.

The other difficulty worth noting about sharing spectrum settings (aka ‘Light Recipes’) is that they are cultivar specific and microclimate dependent.