Please Help me pick a CMH Light

I know i change my mind as often as i do my undies lol but this is the one im thinking of buying.
BESTVA Reflector Series 2000W LED Grow Light Full Spectrum Grow Lamp for Hydroponic Indoor Plants Veg and Flower (Elite-2000w)

You see that part I circled up above. Almost every light out there will have a small usually hidden in the middle section telling the real power draw. There’s no such thing as “replacement wattage” or whatever they want to call it. With lower end LEDs you’ll need 50 watts per square foot of coverage. With high end LEDs like HLG quantum boards, or Rapid led, or my personal favorite a DIY built light you’ll only need 30 to 35 watts per square foot of space.

Your 4’x4.5’ tent is 18 square feet. So with blurple lights or other cheap brands you’ll need closer to 800 actual watts or with high end lights you’ll need somewhere between 550 and 650 watts. By the time you add enough cheaper lights to hit the same amount of photons as the high end lights the cost will be about the same.

I didn’t mean for this to turn into a novel lol. But my point is if you are able to afford better lighting upfront it’ll save you headache in the long run assuming you plan to continue this hobby. When you play mother nature the hardest part to copy is the sun. It’s also the most important part in my opinion. Because even the best grower out there can’t do much without adequate lighting.


Ugh changing my mind a gain but can use some serious growers opinions on this ok…

Horticulture Lighting Group HLG 100 V2 3000K Quantum Board LED Grow Light Veg & Bloom | Version 2 High-Efficiency Upgraded LM301B LED’s

Those are great but you’d need 5 of them.

Or 2 of these from horticulture lighting group

260W QB V2 Rspec LED Kit

Or one of these
QB Kits 600W QB288 V2 R spec LED Kit

Or the other option is to use less space with less plants to lower your lighting needs. That way you can add plants as you buy more lights later.

1 Like

My local guys talked me into leaving HPS behind and going full CMH. I listen to them because they are like Juggernauts in the game. I didn’t even know about the war between 31’s and 42’s when I bought them. I was sold the 42’s and when I ask about this subject now they laugh at me and say the only people who say these things are people trying to sell dirty old 3100 stock from last year. They refer me to the actual lighting spectrum which shows the Japanese Bespoke 4200k in the Hellion Adjusta Wings system to have a higher red spectrum then a DE Lumatek 600w Hps about 0.2 higher and way way WAAAYYYYA wider wavelength and intensity… it sits at between 1.0 and 1.2 in intensity and has no breaks in its wavelength which on the Box is like 2 inches long!! And yes it also has like 500 times more blue spectrum then any and all his lights aswell as every single spectrum you can get… this globe has more red and blue and green and yellow and everything then a DE 1000w HPS ??? So what is everyone talking about I don’t get it is it that like, a million yesrs ago B.C,… CMH Globes were shit? Or just the Phillips? The spectrums shown on here and other websites in comparison posts and stuff show they CMH Lights to sit at like… 0.20 in blue and 0.10 in red… bahaha what the hell? That ain’t right!! My shit sits at 0.90 blue and 1.20 red… I dunno what Phillips has been up to or if the shit you’s run with is old technology or what but the Globes from Japan made by Bespoke… and packaged by Hellion Adjusta Wings is insanely better then everything else hey… at 1st when I was reading all this stuff early on I was like oh shit I better go Chuck in some red spectrum HPS nake it mixed spectrum… but then when I went and checked all the figures I was like… why the do I wanna supplement my spectrum with some shifty HPS globe that doesn’t even have half not even a quarter of the red as my Bespoke CMH Globes already have?

anyway that’s day 7 of flower… If that was HPS it would take like 2.5-3 weeks to look like that but hey 1st run under CMH I’ll let you know how it goes…


The change in color rendering index needs to be accounted for. Most aren’t growing with light source that high, so discussing in more basic terminology is plenty suitable. Their are leds that put all of the cmh bulbs to shame in both ypf and ppf/watt.

Care to take a guess of the cct there? Doesn’t hurt its capable of producing almost 40% more par per watt, and almost all light emitted is within the par region.

Also important to consider that the distribution graphs only show intensity of each wavelength in comparison to others in from that particular light. A light that has total flux of 1200 umols/s doesn’t emit more red light than a light that’s 2100 umols/s just because it shows a little higher intensity there on spd.

What is that chart for?

LED? And how many watts?

Spectral distribution graph on Nichia optisolis 5000k. They are available in pcb configuration as many watts as you want.

1 Like

that’s a Bespoke 315 globe in a Hellion Adjust A Wings. It produces alot of different UV and causes high Terps and very high THC. Infrared light etc. For just 315 watts it’s crazy have you seen when they up the watts to 630? Insane.

Uv and infrared light are both outside of par region. And the most supportive study for uv states it could potentially move thc content from something like 24% thc to 25% thc. Imo that small of an increase isn’t worth using lighting that’s is so much less efficient.

1 Like

I’m going to go research that one you sent right now I’m not versed in LED I came from HPS Land and I was very happy with HPS. I have been converted to CMH for now and I think they’ll be ok… They did 6 weeks veg in 2 weeks… they’ve done 7 weeks flower in 4 weeks… I had my usual concerns and worries threwout early on at the usual times haha… the verdict is not in yet… but we will see… And obviously LED is something I am about to take a journey on I have wanted to for some time but the Juggernauts in the industry have always steered me well away from LED but with the introduction of Gavita throwing they’re hat in the LED ring… Among others… technology today… maybe it’s an option? In the begining it was about efficiency… but then CMH came along and threw them right out on the street… so… it LED can match either efficiency accompanied by quality… Or efficiency accompanied by yeild and almost quality… Then they are an option! As I said I’m not versed in LED I tried to be versed in LED like 100 times over the last however many years becsuse of the efficiency benefits over HPS but I was always turned away by the “experts” they would laugh at me and tell me “you know man you really need stop reading this internet nonsense”… so haha never did end up taking the LED journey… although for the 1st time EVER I saw in they’re shop an LED LIGHT!! Wow!!! Haha it was a Gavita LED light… but I’m defiently open to information education knowledge learning within this LED Journey… If it really works… it takes a fair bit of confidence to drop 30k on lights.

1 Like

Teach me how many watts at the wall I need to cover 4.8m x 4.8m… in LED that will cover the space and produce minimum a pound per 4x4ft given the best of the best everything including Nutrients, oxygen, training, technique. And the rest. What’s the power at the wall to cover that in LED and what will produce 50cm Colas the width of coke cans at the sites. Please.

For instance it takes 3200w at the wall in CMH to cover a size 2 times a 2.4x2.4m. I can’t remember the actual size on paper.

There is nothing wrong with hps or cmh. Cmh definitely more efficient than all of the standard hps rigs, and about the same as de gavita pro 1000. I agree the spectral distribution on cmh makes it winner there.

As far as gavita and led, they are a bunch of posers. For years all the did was talk shit about led, when they finally acknowledged they were getting smoked they went out and copied the fluence fixtures. Then they sold out to the mothership so $uck them. I wouldn’t grow with their lights if they were given to me lol.

Led tech passed any of the hid options about 3-4 years ago. The good stuff was just too expensive for most to buy into. Prices are coming down and efficiency increases are still being made, but at a much slower rate. You will see UVB become available in leds over next year or two, then even the most die hard hid growers will be testing the waters. When I got into led game a single uvb led was about $250. Now they are about $50 and ready to use modules are becoming available.

Depends on which fixture you’re going with. The latest and greatest are at 3 umol/joule. That’s 33% more light per watt, so a 33% reduction in power would put you at roughly the same ppfd average.

The good led fixtures right now in hands of experienced grower are producing more like 2 units per 4x4.


UVB… those are those violets u mentioned eh? Bougie lights :joy: