Led vs Cmh

1KTrees

1KTrees

Member
CobKits said:
CRI-ness envy, eh?
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There is cree-nis and now cri-nis envy.

It seems like there is so much unknown about lighting and canna that it feels like throwing darts in the dark.

The next best thing might not actually be as great as it is on paper.

We'll need a new lighting term or 2.
The GSR(grow sativa rating) is 3.76
The GIR(grow indica rating) is 2.97
@18" from canopy.
 
Greengenes707

Greengenes707

Well-Known Member
CobKits said:
can we agree that the standard yardstick of PAR is inherently flawed as it:
-gives equal weight to wavelengths from 400-700
-expressly disregards activity of UV and IR wavelengths jsut above and below this? we know uv aids in trich expression, and emerson effect is a real concept which is totally disregarded by classic PAR measurement

also what are your thoughts on McCree/YPF? is that single leaf study inherently flawed based on modern day science? obviously we know from experience that 580-730 give the best return, and blue is necessary to a point (but inhibits above a certain point). Also it appears that for best vigor and full development, we do in fact need the intermediate actinic/green/yellow bands (commonly found in phosphor led spectra, and supplemented to mono-based led fixtures as "warm white".) but how much white do we need? at what point is it diminishing returns?
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VVVV
Greengenes707 said:
I hate 400-700 as "PAR" I always prefer everything the light source has to offer...UV or IR sides of it.

PAR by definition is anything that drives photosynthesis. With that said...all the way up to 725nm has over 25% RQE. It seems pretty silly to only use 400-700nm to me...plants feel that way too, whether for slight growth, or photomorphis and in turn gaining surface area to have more photosynthesis via more reactions, not faster rate of photosynthesis(efficiency).

The question is always are the gains worth the losses. Do you get a net gain...? Experimenting is and has been going on. It will come to light eventually, but right now there is nothing definitive within the parameters we are working with.
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CobKits said:
in the end it seems that many experienced growers who switch from 80 to 90 (and to a lesser extent 3500 to 3000k) seem to be happier with the results in bloom, despite the lower PAR numbers (on a PPF/W basis). so what equivalence can we consider between say a 3000k 90 and a 3500k 80? is 90% of the PAR required to achieve the same results. electrical input wise its the same in many cases.

sorry just rambling, i know that was all over the place. im escaping the winter of hell and about to find time to get serious with the sphere. i dont want to just generate data. i want to generate useful data that we can do something with, and these questions eat me up. im about to throw away the steeply filtered li-cor in favor of a broader photodiode to measure 300-800nm and maybe we can correct back to whatever we think the most appropriate definition of "PAR" is for our purposes. im pretty sure that the pro light labs who measure ppf are just sharply truncating those wider spectrum measurements to 400-700nm - 90 cri will lose every time in this case
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VVVV
tags420 said:
How do you think 3500k got so popular. Most originally were only using 3K cause that's what the guy thy copied did. Then someone tested others openly for everyone to see. The promise of that the extra bin made up for any morphology and spectral shifts. It also maintained near absolute values of the 3K but with a slight blue bump. Ow and behold it was just as science has said for years...photons first.
It is funny is that everyone wants to stay up there. I sure as hell don't. If 3K and 3500K were the same bin we would never have drifted up in the first place. And at one time back with CXA(ya, most of you new cob puppies weren't even RIU member or led users) 4K was where the bin jump was. An hence why it was tested first. Not to mention all the vero testing that went on back then too. With their phosphors erring on the warmer side of the "official" CCT. Then people actually used them in the real world too. Not data sheet humping.(didn't say anything didn't work...just that humping the data sheets isn't the way to show use in the real world).

As for phosphors...They are nearly all the same. Check cross licenses on white leds...most of nichia patents are still in effect.
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3500K(80cri)...3000K(80cri)
IMG_5031.jpg

4000K....6K+630...3000K
IMG_5485.jpg

4000K cxA(80cri)...3000KcxB(80cri)...same bins.
IMG_6651.jpg
 
CobKits

CobKits

Well-Known Member
so i guess that answers my one question... doesnt seem like years and many grows later were any closer to a consensus... thanks for the input. i can see why youre not around much any more, how many times can you repeat yourself?
 
1KTrees

1KTrees

Member
CobKits said:
so i guess that answers my one question... doesnt seem like years and many grows later were any closer to a consensus... thanks for the input. i can see why youre not around much any more, how many times can you repeat yourself?
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So, was photons first the take away from that?
 
Greengenes707

Greengenes707

Well-Known Member
CobKits said:
not at all. not all photons are created equal otherwise wed all be using 450nm monos
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Here is more from the same thread from a year ago I keep pulling things from. Not the first time, and surely not the last time we will go around this merry go round.
The main goal is always the same...
Greengenes707 said:
I have said it a million times...pay attention to my WHOLE statement.

The main goal of a grower is to provide the maximum amount of photons while still staying within plant requirements.

Ready, set,...Google
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Maybe your name change from @BOBBY_G made you forget @CobKits. Give it a re-read...
https://www.rollitup.org/t/3500k-vs-4000k-vs-5000k.910643/

More to read...
https://www.rollitup.org/t/farred-photosynthesis.842295/
https://www.rollitup.org/t/summer-2014-led-growing-notes.837071/
Classic...
https://www.rollitup.org/t/cree-cxa-3000k-80cri-spectrum-analysis.832666/
Great, but new phosphors make a better case, but the principals and data is all still valid
https://www.rollitup.org/t/cxa-3000k-80-vs-93-cri-an-estimation.833171/
 
CobKits

CobKits

Well-Known Member
lol sorry i opened up the conversation. we cant resurrect every year old 300 post thread ;)

happy friday will be tuning in to growtube as usual
 
1KTrees

1KTrees

Member
Greengenes707 said:
Here is more from the same thread from a year ago I keep pulling things from. Not the first time, and surely not the last time we will go around this merry go round.
The main goal is always the same...

Maybe your name change from @BOBBY_G made you forget @CobKits. Give it a re-read...
https://www.rollitup.org/t/3500k-vs-4000k-vs-5000k.910643/

More to read...
https://www.rollitup.org/t/farred-photosynthesis.842295/
https://www.rollitup.org/t/summer-2014-led-growing-notes.837071/
Classic...
https://www.rollitup.org/t/cree-cxa-3000k-80cri-spectrum-analysis.832666/
Great, but new phosphors make a better case, but the principals and data is all still valid
https://www.rollitup.org/t/cxa-3000k-80-vs-93-cri-an-estimation.833171/
Click to expand...
Thanks I'll check it out
 
Leandrobcool

Leandrobcool

Active Member
I have the possibility to buy a diy cob cxb 3590 in 3k or 3,5k both at 80 cri, Wich one is better, considering that I want to use the same light from seed to harvest?
Is the 3k better in flowering with more frost and denser buds, as for the 3,5k has a better light for veg than 3k, but it looses a notch in flowering?
That's the beauty of it so many possibilities that u not even know where to turn to:)

When u think is over it just comes around again.
 
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Sanctifried

Sanctifried

Member
Leandrobcool said:
I have the possibility to buy a diy cob cxb 3590 in 3k or 3,5k both at 80 cri, Wich one is better, considering that I want to use the same light from seed to harvest?
Is the 3k better in flowering with more frost and denser buds, as for the 3,5k has a better light for veg than 3k, but it looses a notch in flowering?
That's the beauty of it so many possibilities that u not even know where to turn to:)

When u think is over it just comes around again.
Click to expand...
I would go with the 3500.


But to add my 2 cents into this conversation, I'm running a full spectrum LED beside a CMH right now. You know which one is producing better? The LED. You know which one is cooler? The LED. CMH is a fad and will die away. I have reason to believe the only reason for the CMH market is due to a surplus in materials needed to make CMH bulbs, so to get rid of tons and tons of nearly useless material a new market was created.

This is why i dont like CMH:

Needs to be 2-3 feet away from canopy to avoid foxtail.
Runs on a fucking ballast.
Runs on fucking bulbs that you have to replace and worry if they blow.
ZERO light penetration. The leaves and buds under the canopy are pitifully under-grown and will be no good. I dont have an extra room for drying so i can't remove the tops and let the bottom finish.
UV rays? Thanks for the eye damage. The most terpy plant I have it under the goddamned LED. ITS ALL ABOUT GENETICS.


CMHs are bullshit. Don't fall for it. LED all the way.

LED has the zero infa red which tricks the plant into photosynthesizing more than usual. Plants under the LED needed more feeding than under the CMH, seriously, don't buy brand name LEDs yet, most of them suck balls, go with a guy who knows what hes doing and have him help you do the DIY. You'll get better results and save fucking bank.
 
frica

frica

Well-Known Member
Sanctifried said:
I would go with the 3500.


But to add my 2 cents into this conversation, I'm running a full spectrum LED beside a CMH right now. You know which one is producing better? The LED. You know which one is cooler? The LED. CMH is a fad and will die away. I have reason to believe the only reason for the CMH market is due to a surplus in materials needed to make CMH bulbs, so to get rid of tons and tons of nearly useless material a new market was created.

This is why i dont like CMH:

Needs to be 2-3 feet away from canopy to avoid foxtail.
Runs on a fucking ballast.
Runs on fucking bulbs that you have to replace and worry if they blow.
ZERO light penetration. The leaves and buds under the canopy are pitifully under-grown and will be no good. I dont have an extra room for drying so i can't remove the tops and let the bottom finish.
UV rays? Thanks for the eye damage. The most terpy plant I have it under the goddamned LED. ITS ALL ABOUT GENETICS.


CMHs are bullshit. Don't fall for it. LED all the way.

LED has the zero infa red which tricks the plant into photosynthesizing more than usual. Plants under the LED needed more feeding than under the CMH, seriously, don't buy brand name LEDs yet, most of them suck balls, go with a guy who knows what hes doing and have him help you do the DIY. You'll get better results and save fucking bank.
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Well...

Sanctifried said:
Needs to be 2-3 feet away from canopy to avoid foxtail.
Click to expand...
That's an issue with CMH.

Sanctifried said:
Runs on a fucking ballast.
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LEDs use drivers, same shit.

Sanctifried said:
Runs on fucking bulbs that you have to replace and worry if they blow
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The bulbs actually last pretty long, not as long as LEDs.
But as long as you don't have 80-90% efficient LEDs they will be replaced in a few years anyway, so a moot point currently.

Sanctifried said:
ZERO light penetration
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Nothing to do with the light, more to do with using it in a too large space or having it too far off the canopy.
LED will have the same issues if you (for example) use a 50W light to cover 2 square foot.

Sanctifried said:
UV rays? Thanks for the eye damage. The most terpy plant I have it under the goddamned LED. ITS ALL ABOUT GENETICS.
Click to expand...
UV does increase THC production.

Though I see people growing shitty autoflowers all the time so I guess it's still a moot point because genetics are more important than UV.
And maybe modern super high THC strains don't even produce more THC from UV because they're already producing so much naturally.


LEDs do have some infra red, probably enough for the emerson effect.

Sanctifried said:
Plants under the LED needed more feeding than under the CMH
Click to expand...
If you massively increase light intensity the plants will need more feeding.
I think you used the CMH in a too large space for the wattage.
 
Sanctifried

Sanctifried

Member
frica said:
Well...


That's an issue with CMH.


LEDs use drivers, same shit.


The bulbs actually last pretty long, not as long as LEDs.
But as long as you don't have 80-90% efficient LEDs they will be replaced in a few years anyway, so a moot point currently.


Nothing to do with the light, more to do with using it in a too large space or having it too far off the canopy.
LED will have the same issues if you (for example) use a 50W light to cover 2 square foot.


UV does increase THC production.

Though I see people growing shitty autoflowers all the time so I guess it's still a moot point because genetics are more important than UV.
And maybe modern super high THC strains don't even produce more THC from UV because they're already producing so much naturally.


LEDs do have some infra red, probably enough for the emerson effect.


If you massively increase light intensity the plants will need more feeding.
I think you used the CMH in a too large space for the wattage.
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Good points. I can concede on a few of my points. Honestly I am going to go 80% LED as the primary lighting, CMH as the remaining. Cool temps means less electricity cost and the penetration of LED is great. I will test potency of nugs from each light and post the results later. Harvesting tmrw, actually.

My post may have been a bit salty against CMHs because it dissapointed me, thats my fault for having high expectations. Yet I'm still going to use them as a supplement for efficient UV and good par.

Still, though, can't argue that CMHs are a fad. In a year or two LEDs are going to outperform everything. I'm not going to fill a 10x10 or a 20x30 grow with CMHs, I'll take an LED that'll last 10 years, even when outdated itll be the best veg light i have.
 
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