Light Quantity vs Light Quality Evidence ... Just for 4 u gg lol!

That's why I used to run like this sometimes at the begging & end of flower. Hortrilux Red Mixed w/ Daylight Blue w/ enhanced white T-5 side-lighting.
Now I'm all led. 80 & 95 CRI.

mauricem00 said:

I love being proved wrong with solid scientific evidence because that one way I learn and become a better grower

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You got that backwards. We have scientific evidence and a half assed test done by some random amateur on the internet is not going to refute that.

I'll take the big test grows done by agriculture universities over this nut's hobby project thank you very much. Unfortunately there are always people who feel the opposite and they will take some random nuts word over actual evidence. That's how we get for instance anti vaxxers and all the damage they are doing.

Besides, I have my own "evidence". I used to get for instance 1220g from a 1000W HPS (1150W draw on boost) and now 600g from 400W Cree COB. In both cases that comes out at almost the exact same amount of grams per light quantity. Around 0.76g/umol/s. So the spectrum mattered pretty much nothing between those two.

Every scientific test indicates that spectrum quality matters only marginally for yield while quantity has almost a linear relation to yield. So yeah, I call bullshit on this thread and with a whole lot of good reason.

Here is a link to the University of Utah testing of CMH. Yes I know this thread was testing LED but there is related info here. And good comparison graphs.

https://www.cycloptics.com/sites/default/files/USU_spectral_analysis.pdf

I am slow to catch up with technology and have only recently added 315 LEC to my air cooled Hortilux Super HPS flower room. All I can add is the penetration and footprint from the HPS is greater but I already can see and feel quality differences from using the better spectrum with some uv to finish the flowers during ripening. The uv may be the most significant part here but the link is about spectrum.

But my system was about 25% low on Blue light to reds with only HPS. So bumping up the room to a better spectrum and using it as a finishing lamp has increased the quality of the smell appearance and high in the last three plants of familiar strains.

But yield would suffer if I switched to the lower wattage higher tech bulb over the 600's for sure. Underdeveloped lowers at least.

So as usual there is some truth to both sides of the argument

Also in this particular industry yield can be counted in different ways. You can count overall carbon weight but you can also see which yields higher in total extraction.

If it was totally about photon count then low pressure sodium would rule the roost.

In my opinion spectrum can make about a 10%-15% difference in overall yield . That's about it.

Carry on

@MichiganMedGrower, That paper just shows spectral distributions. It doesn't relate it to anything.

The point is that this thread provides us with hard evidence that:
1) White led light produces is 37% more efficient using similar quantities of light.
2) Cutting the total amount of led light almost in half gives you exactly the same yield

Both of those findings go completely against what any scientific research on the matter has shown. So what does a scientist conclude from that result? Is it:
A) "Wow, my 'evidence' is completely contrary to what you would expect, so I must be a genius and everybody else was wrong"
B) "Oh crap I must have messed up my experiment and neglected to keep other parameters equal over the different grows. Better fix what I did wrong and try again"

Usually HPS spectrum actually outperforms white leds by a tiny margin. Red+Blue lights tend to outperform HPS spectrum a little. When plants are given the same amount of light in umol/s under all light sources. Either way, the differences are, as @Stephenj37826 says, only marginal and that's with massively different spectral distributions.

Going from 300 to 600umol light intensity will not give you the same yield as this "experiment" shows, but under similar conditions the yield would almost double.

A 10% difference is difficult to measure with a hobby grow since you can easily have that kind of variation already between grows using the same genetics and same light.

Especially if you compare a single plant to another single plant. I have seen plants yield twice as much as the plant next to it. Even though they were right next to each other and therefore under the exact same spectrum. So you have an error margin of probably at least 50% if you compare single plant crops. Which means that you will never see significant differences (where significant means "outside of the margin of error of the experiment")

I feel if you have a good quantity of the right quality (flower/veg) then you're doing better off then picking one or the other for sure.
This day n age you don't have to pick between them. You can have both.
10% increase ='d 1 extra # for my last room.
Actually got a 25% increase using low wattage side-lighting. It made a huge difference to me & was nothing to sneeze at.

Adding mono's to COBs is both a hassle and it adds to the cost of the build. No one even knows or agrees on what "good quality" light exactly is. So benefits are anecdotal at best.

Even if there are suggestions that one spectrum is "better" than another then it's usually only based on a single aspect and what is actually better can completely change in a slightly different scenario

For instance 90% red plus 10% blue is most efficient for chlorophyll photosynthesis (or at least more efficient than HPS or phosphor coated leds). Yet when you use this purple light for cannabis you quickly get problems with bleaching if you want to apply higher light intensities.

Or another example is adding FR. That might create more biomass, but it also induces a lot of stretch. In a test done by a dutch university, the (tomato) plants receiving FR were leading the others by quite a margin during veg. Yet through productive phase (flowering) they fell behind the plants which had not received extra FR and were more sturdy as a result of not stretching so much.

wietefras said:

Adding mono's to COBs is both a hassle and it adds to the cost of the build. No one even knows or agrees on what "good quality" light exactly is. So benefits are anecdotal at best.

Even if there are suggestions that one spectrum is "better" than another then it's usually only based on a single aspect and what is actually better can completely change in a slightly different scenario

For instance 90% red plus 10% blue is most efficient for chlorophyll photosynthesis (or at least more efficient than HPS or phosphor coated leds). Yet when you use this purple light for cannabis you quickly get problems with bleaching if you want to apply higher light intensities.

Or another example is adding FR. That might create more biomass, but it also induces a lot of stretch. In a test done by a dutch university, the (tomato) plants receiving FR were leading the others by quite a margin during veg. Yet through productive phase (flowering) they fell behind the plants which had not received extra FR and were more sturdy as a result of not stretching so much.

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Filling the gaps in regular 70-80 CRI white makes a true full spectrum. What that does for your garden is up to you to decide. I feel it's advantageous & choose to go that route myself. Pre-built took away all the hassle.

wietefras said:

@MichiganMedGrower, That paper just shows spectral distributions. It doesn't relate it to anything.

The point is that this thread provides us with hard evidence that:
1) White led light produces is 37% more efficient using similar quantities of light.
2) Cutting the total amount of led light almost in half gives you exactly the same yield

Both of those findings go completely against what any scientific research on the matter has shown. So what does a scientist conclude from that result? Is it:
A) "Wow, my 'evidence' is completely contrary to what you would expect, so I must be a genius and everybody else was wrong"
B) "Oh crap I must have messed up my experiment and neglected to keep other parameters equal over the different grows. Better fix what I did wrong and try again"

Usually HPS spectrum actually outperforms white leds by a tiny margin. Red+Blue lights tend to outperform HPS spectrum a little. When plants are given the same amount of light in umol/s under all light sources. Either way, the differences are, as @Stephenj37826 says, only marginal and that's with massively different spectral distributions.

Going from 300 to 600umol light intensity will not give you the same yield as this "experiment" shows, but under similar conditions the yield would almost double.

A 10% difference is difficult to measure with a hobby grow since you can easily have that kind of variation already between grows using the same genetics and same light.

Especially if you compare a single plant to another single plant. I have seen plants yield twice as much as the plant next to it. Even though they were right next to each other and therefore under the exact same spectrum. So you have an error margin of probably at least 50% if you compare single plant crops. Which means that you will never see significant differences (where significant means "outside of the margin of error of the experiment")

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The paper I linked agrees with you in the text before the graphs. The plants will utilize whatever spectrum is present most and transfer the photodynthesis but up to a point the balanced spectrum helps.
I am saying that the claims of cmh bulbs are just like the claims of this thread. Not quite true. They don't compete well with my 600 HPS but do offer other benefits.

If I tried to grow my garden with the low intensities used in this test patients and I would be short of the potent meds we need.

I am keeping my HPS and supplementing spectrum.

Both sides of the argument have validity but I agree you can't prove shit with 3 tomato plants and a thread.

this is beginning to sound like a group of lawyers arguing.you can find "scientific studies" to prove any point you want to make.in the real world. greenhouse and garden center operators rely on experience. a few years ago NPR held a seminar bringing together business school professors and silicon valley executives. when they interview these people after the seminar both .groups claimed that the other did not know what they were talking about. I think the experience of successful business men carries more weight that the theories of a group of college professors. most of what I know about growing I learned from nurseries, garden centers and professional gardeners. at these businesses I do not see LEDs or HPS lights in their indoor gardens. what I do see is T8s, T5s and MH lights.I believe these successful business men know more about growing plant than some college professor. but then I grow in soil and not on chalk boards

I have a CXB 3590 light from Timber (an older prototype) in 4000K and I wanted to add some red to the spectrum so @RainDan and Co. built me some 18" bars with 6 red diodes in each. It adds a total of 24 watts for both bars. Since I always grow plants from regular seeds, I can't ever tell what kind of phenotypes I might get. So I can't tell if adding the reds will make a big difference or not. Each phenotype does its own thing in its own way and how they respond to the spectrum may be different, too. But, the plants are growing well and I figure it can't hurt anything.

mauricem00 said:

this is beginning to sound like a group of lawyers arguing.you can find "scientific studies" to prove any point you want to make.in the real world. greenhouse and garden center operators rely on experience. a few years ago NPR held a seminar bringing together business school professors and silicon valley executives. when they interview these people after the seminar both .groups claimed that the other did not know what they were talking about. I think the experience of successful business men carries more weight that the theories of a group of college professors. most of what I know about growing I learned from nurseries, garden centers and professional gardeners. at these businesses I do not see LEDs or HPS lights in their indoor gardens. what I do see is T8s, T5s and MH lights.I believe these successful business men know more about growing plant than some college professor. but then I grow in soil and not on chalk boards

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The data from the indoor lighting research at the University of Michigan and the Univertisy of Utah is the data used by professionals in the indoor gardening industry. The research exists to help our farmers.

And both greenhouses I have been to here had HPS supplemental lighting.

and I have only seen flourescents tubes in the nursery.

What businesses are you talking about that don't use researched data before buying expensive equipment?

MichiganMedGrower said:

The data from the indoor lighting research at the University of Michigan and the Univertisy of Utah is the data used by professionals in the indoor gardening industry. The research exists to help our farmers.

And both greenhouses I have been to here had HPS supplemental lighting.

and I have only seen flourescents tubes in the nursery.

What businesses are you talking about that don't use researched data before buying expensive equipment?

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home depot, lowes, walmart and the local nurseries. I think these large companies do research options before buying. HPS lights are used for supplemental lighting during winter to create a longer day but not as stand alone grow lights.NASA has been doing research on grow lights for years as well.as have many universities.

for every study you can show me saying spectrum does not matter I can show you one or more that say it does https://www.uaf.edu/files/ces/publications-db/catalog/anr/HGA-00432.pdf you can even find studies that show all you need to grow plants is deep red (660nm) and royal blue (450nm) leds https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3949401/ I hope i'm not offending you but two people can have different opinions and discuss their views rationally. I am not looking for a fight.what I use works very well for me as PU MMJ closet grower but it is not the only way to grow cannabis.

mauricem00 said:

for every study you can show me saying spectrum does not matter I can show you one or more that say it does https://www.uaf.edu/files/ces/publications-db/catalog/anr/HGA-00432.pdf you can even find studies that show all you need to grow plants is deep red (660nm) and royal blue (450nm) leds https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3949401/ I hope i'm not offending you but two people can have different opinions and discuss their views rationally. I am not looking for a fight.what I use works very well for me as PU MMJ closet grower but it is not the only way to grow cannabis.

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The best way to know is to do it for yourself. I did spectrum testing for about 18 months and have come to my own. conclusions. Quantity and quality go together hand-in-hand to get the best results possible.

wietefras said:

You got that backwards. We have scientific evidence and a half assed test done by some random amateur on the internet is not going to refute that.

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Ooooh looks whose spat his dummy out and is having a temper tantrum... Clearly you are too thick to know the distinction between an amateur and a professional, looking at your ridiculous comment here I guess in your book a professional means a big corporation or university... Pmsl

wietefras said:

I'll take the big test grows done by agriculture universities over this nut's hobby project thank you very much. Unfortunately there are always people who feel the opposite and they will take some random nuts word over actual evidence. That's how we get for instance anti vaxxers and all the damage they are doing.

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Seriously what the heck are you talking about??? Because in and amongst all your jibberish drivel I completely fail to see your point???

wietefras said:

Besides, I have my own "evidence". I used to get for instance 1220g from a 1000W HPS (1150W draw on boost) and now 600g from 400W Cree COB. In both cases that comes out at almost the exact same amount of grams per light quantity. Around 0.76g/umol/s. So the spectrum mattered pretty much nothing between those two.

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Yeah of course you have your own evidence well until you produce the pics I am saying you didn't do jack and I am calling Bs on your comment, especially in light of your omission with regards to quality... clearly you are talking out of your rear end as per usual

wietefras said:

Every scientific test indicates that spectrum quality matters only marginally for yield while quantity has almost a linear relation to yield. So yeah, I call bullshit on this thread and with a whole lot of good reason.

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HAHAHHAH you really are a lying twat.... If your post was remotely true then why are the big players you so love, like Phillips researching and creating light recipes, besides who said it was all about yield, what about quality of produce???

Once again you have shown, how you are too thick to even comprehend what you are reading. If you were an Actual grower rather than a serial non-reader you would have observed the completely obvious, your post exposes your lies lol.

For the record even the professionals acknowledge spectrum plays a key role in Yield and quality, If spectrum is not important in terms of quantity and quality of yield produced then why do you suppose the big players are taking it seriously???

Read and weep you complete and utter moron!!!

http://www.usa.lighting.philips.com/products/horticulture/light-recipe.html

http://www.usa.lighting.philips.com/products/horticulture/vegetables-and-fruits.html

http://www.ledsmagazine.com/articles/2015/07/leds-in-horticulture-philips-growwise-center-and-purdue-studies-space.html

https://www.heliospectra.com/blog/light-recipes-seamless-transition-led-grow-lights

http://www.hortweek.com/led-lighting-systems/products-kit/article/1390337

https://horticulture.ahdb.org.uk/sites/default/files/u3089/Lighting_The-review.pdf

http://illumitex.com/research-light-speed-806

http://illumitex.com/austininno-basil-marijuana-acne-led-tech-company-lighting-future-743

mauricem00 said:

home depot, lowes, walmart and the local nurseries. I think these large companies do research options before buying. HPS lights are used for supplemental lighting during winter to create a longer day but not as stand alone grow lights.NASA has been doing research on grow lights for years as well.as have many universities.

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I can't tell if you are arguing or agreeing?

And you are using retail warehouses as an example of grow lighting? They use light that makes the merchandise look good to us. I managed car dealers in my career. We used daylight flourescents in our showroom. The house plants around the showroom thrived and the cars looked nice. Does that experience help me grow meds?

I am the one who linked the university data. There is tons more that mostly proves lumens trump spectrum. But they have proven the blue light theories too. Just only works up to a point. About 50/50. And minor effects from the rest of the spectrum.

What kind of research do you think NASA conducted? Their research does not contradict the universities.

My point is with our flowers. Yield per square foot is still intensity dependent and the quality of the product is improved with spectrum but only to a point.

And the tomato plant project in op of this thread doesn't prove anything about anything but those little tomato plants and the opinion of the writer.

Of course, neither side of the "argument" is correct. There are benefits both ways.

MichiganMedGrower said:

The paper I linked agrees with you in the text before the graphs. .

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Yet more evidence that the numbnut called Wietefras cannot understand what he is reading LOL !!!

tstick said:

I have a CXB 3590 light from Timber (an older prototype) in 4000K and I wanted to add some red to the spectrum so @RainDan and Co. built me some 18" bars with 6 red diodes in each. It adds a total of 24 watts for both bars. Since I always grow plants from regular seeds, I can't ever tell what kind of phenotypes I might get. So I can't tell if adding the reds will make a big difference or not. Each phenotype does its own thing in its own way and how they respond to the spectrum may be different, too. But, the plants are growing well and I figure it can't hurt anything.

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You raise a good point with regards to different phenotype can/will respond differently, clearly the ones who are not getting it are the ones who have not took the time to test stuff out, yet they want to preach their false gospel of Scientism rather than dealing in "Actual" observable scientific Facts!

mauricem00 said:

home depot, lowes, walmart and the local nurseries. I think these large companies do research options before buying. HPS lights are used for supplemental lighting during winter to create a longer day but not as stand alone grow lights.NASA has been doing research on grow lights for years as well.as have many universities.

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Not be be condescending but i didn't know NASA was in the cannabis grow bizz.