The Impact of Light Intensity and Spectrum-Tuning on Cannabis Yields

Coalcat

Coalcat

Well-Known Member
Very very interesting study for led users. Basically amount of light is more important than specific spectrums. Commercial broad spectrum leds (strips/3000k boards)are better than tuned (burple). Finally leds are about 40% more efficient at doing this than hps.


https://poseidon01.ssrn.com/delivery.php?ID=872119091124113027026103000122093087049073070064025021111113076102071094101118124000120032062006006027002112107105105071026004000029026049019118078084024092091011034006054124064097004065096123067073028002112079070124096107086115103082104101070125086&EXT=pdf
 
xtsho

xtsho

Well-Known Member
I guess people like to pick and choose what they want from that study. It states that the fancy expensive LED's everyone brags about are not the best light to use.

"Rather, the more profitable strategy would be to buy commoditized, high-intensity, broad-spectrum LEDs (like flood lights), which are about one-third the cost per watt of horticulture LEDs.

The second reason these results are important is that the vast majority of growers use HPS lights. Those who use LED lights are using lights that were designed to use less electricity while providing the same light intensity as an HPS. Our results suggest that both these strategies reduce the grower’s expected profits, since both provide less light than is optimal when trying to maximize yields. The electricity saving offered by lower powered LEDs are far smaller than the yield value lost by reducing light intensity."
 
hillbill

hillbill

Well-Known Member
COBs and Boards fit the bill and are way less costly than my own discreet diode, high end white panels. Most light per watt.

The new CMH lights seem a reasonable choice also. Hortilux bulb is interesting too!
 
Chris Edward

Chris Edward

Well-Known Member
Coalcat said:
Very very interesting study for led users. Basically amount of light is more important than specific spectrums. Commercial broad spectrum leds (strips/3000k boards)are better than tuned (burple). Finally leds are about 40% more efficient at doing this than hps.


https://poseidon01.ssrn.com/delivery.php?ID=872119091124113027026103000122093087049073070064025021111113076102071094101118124000120032062006006027002112107105105071026004000029026049019118078084024092091011034006054124064097004065096123067073028002112079070124096107086115103082104101070125086&EXT=pdf
Click to expand...
This is interesting, I will give you that.
But it's one study among many others that say otherwise.
I mean Philips has built an entire sideline business geared around the importance of LED spectrum as well as an entire series of lights based on the whole "light recipe" thing.
http://www.lighting.philips.com/main/products/horticulture/light-recipe
That's a lot of money to invest into an idea that doesn't show promise.

Somewhere I video from a British TV show where they toured one of the Philips test centers, it was very enlightening (no pun intended).

In the same TV series they show a bit about a guy who changes the spectrum of light on certain herbs right before packaging because this allows the herbs to deal with the standardized cold shipping conditions and still arrive at grocery stores fresh.

In the attachment is one study I found that shows that light spectrum does in fact have an effect.

Also in the attachment is the "Cornell Hydroponic Lettuce Handbook" it has lots of information about lighting, specifically LED lighting.

There is also another study, I have the pdf somewhere, when I find it I will post it.
It shows how plants (lettuce again) grown under specific spectrum can differ in both the way they look and the nutrients they contain.
This paper helped me when I was making the lights for my "greens" shelving units and I have some of the most perfect lettuce and bok choy that come out of that set up...
Here is a YouTube link to a video that does something similar.
It clearly shows how spectrum directly influences the plants...

Another way to easily test this on your own is to periodically do brix testing on your leaves, which can be done using a cheap refractometer or something like a SCiO pocket spectrometer, it will give you an idea of the nutrient content in your plants, not that you will be eating the leaves, but the leaves are necessary to make flowers...

Ultimately the point of the grow should be a quality yield, not the weight.
We have commercial growers who will soon be ruining the industry by focusing purely on weight while producing trash product and I am sure in the very near future they will even begin (if they haven't already) using recombinant DNA and CRISPR to produce GMO weed.
When that happens it will be the folks who still give a shit and have good, quality yield who will benefit the most (look how companies selling organic food are making bank right now).

Just my 2 cents...
 

Attachments

SMT69

SMT69

Well-Known Member
Chris Edward said:
This is interesting, I will give you that.
But it's one study among many others that say otherwise.
I mean Philips has built an entire sideline business geared around the importance of LED spectrum as well as an entire series of lights based on the whole "light recipe" thing.
http://www.lighting.philips.com/main/products/horticulture/light-recipe
That's a lot of money to invest into an idea that doesn't show promise.

Somewhere I video from a British TV show where they toured one of the Philips test centers, it was very enlightening (no pun intended).

In the same TV series they show a bit about a guy who changes the spectrum of light on certain herbs right before packaging because this allows the herbs to deal with the standardized cold shipping conditions and still arrive at grocery stores fresh.

In the attachment is one study I found that shows that light spectrum does in fact have an effect.

Also in the attachment is the "Cornell Hydroponic Lettuce Handbook" it has lots of information about lighting, specifically LED lighting.

There is also another study, I have the pdf somewhere, when I find it I will post it.
It shows how plants (lettuce again) grown under specific spectrum can differ in both the way they look and the nutrients they contain.
This paper helped me when I was making the lights for my "greens" shelving units and I have some of the most perfect lettuce and bok choy that come out of that set up...
Here is a YouTube link to a video that does something similar.
It clearly shows how spectrum directly influences the plants...

Another way to easily test this on your own is to periodically do brix testing on your leaves, which can be done using a cheap refractometer or something like a SCiO pocket spectrometer, it will give you an idea of the nutrient content in your plants, not that you will be eating the leaves, but the leaves are necessary to make flowers...

Ultimately the point of the grow should be a quality yield, not the weight.
We have commercial growers who will soon be ruining the industry by focusing purely on weight while producing trash product and I am sure in the very near future they will even begin (if they haven't already) using recombinant DNA and CRISPR to produce GMO weed.
When that happens it will be the folks who still give a shit and have good, quality yield who will benefit the most (look how companies selling organic food are making bank right now).

Just my 2 cents...
Click to expand...
I’m seeing all over IG and the many forums, that Leds are producing BETTER quality , some folks are closing their eyes and stuck here on RIU, just let them
 
Chris Edward

Chris Edward

Well-Known Member
SMT69 said:
I’m seeing all over IG and the many forums, that Leds are producing BETTER quality , some folks are closing their eyes and stuck here on RIU
Click to expand...
Some folks insist that LEDS are like Lasers!!!
I saw a video on that and it made me laugh...
Usually the the folks who are resistant are older folks who have always used HPS and they figure "if it ain't broke..."
But it is broke, those things not only use hordes of wattage, but they are also hazards when it comes to disposal.
But then again, they are just as bad as the compact fluorescent folks, which again are hazards when they are disposed of...

But no one looks at that.

They see the $1,000 upfront price tags on the high end LED lights, plus what appears to be a small savings in electrical usage and then compare that to the much cheaper upfront cost of their HPS setups and then they compare that to their current cost for a grow compared to the return on investment.
But they seem to ignore COBS, which especially in kit form are comparatively priced to the start up cost of an HPS system.
COBs, when run at 75% power will last like 10-15+ years before the lights dims enough to be noticeable, at which point it then becomes a clone light.
These same folks don't typically factor in all the HPS bulbs that will need to be changed in that 10-15 years, every 6 months at $30 a pop..
When I built my last COB light, it was about $100 more than a comparative HPS setup.

Then there is the fact that LED prices keep going down and older tech like vacuum tubes, sorry, HPS light prices will continue to go up as less and less people use them...

I under run the LED's and it should lat me about 10 years, so that's like $35 a year.
Compare that to the initial start up costs of an HPS system and the regular bulb changes and over that same period of time you are looking at the system costing you $70 a year, plus the additional wattage...

Whatever, I know LED's work and I can talk myself blurple in the face trying to convince others of that fact, but if they are set on the fact that HPS works, because it's what they have always known, then no amount of fact or reason will change their minds.
Something will just click one day and they will get it and that's all that matters...

If I were ever to ever go with a bulb type light it would be Light Emitting Plasma, that shit is awesome!!!
A bulb the size of a fat grain of rice can kick the ass of any other light out there!!!
EXCEPT during flower because LEP is a blue spectrum light....
Wa Wa Wa....
 

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Johnny Lawrence

Johnny Lawrence

Well-Known Member
xtsho said:
I guess people like to pick and choose what they want from that study. It states that the fancy expensive LED's everyone brags about are not the best light to use.

"Rather, the more profitable strategy would be to buy commoditized, high-intensity, broad-spectrum LEDs (like flood lights), which are about one-third the cost per watt of horticulture LEDs.

The second reason these results are important is that the vast majority of growers use HPS lights. Those who use LED lights are using lights that were designed to use less electricity while providing the same light intensity as an HPS. Our results suggest that both these strategies reduce the grower’s expected profits, since both provide less light than is optimal when trying to maximize yields. The electricity saving offered by lower powered LEDs are far smaller than the yield value lost by reducing light intensity."
Click to expand...
I replaced 2 600 watt HIDs with 900 watts of cobs and have been nailing the exact same numbers for well over a year now. Pulled a 6 out of a 4x4 and replaced it with 450 watts of PCB/cobs - same thing. I still run a 6/750 DE in my big room, but it has 12 foot ceilings.

I live in an area where electricity is incredibly expensive and heat waves are a common occurrence.
 
NoWaistedSpace

NoWaistedSpace

Well-Known Member
Chris Edward said:
Some folks insist that LEDS are like Lasers!!!
I saw a video on that and it made me laugh...
Usually the the folks who are resistant are older folks who have always used HPS and they figure "if it ain't broke..."
But it is broke, those things not only use hordes of wattage, but they are also hazards when it comes to disposal.
But then again, they are just as bad as the compact fluorescent folks, which again are hazards when they are disposed of...

But no one looks at that.

They see the $1,000 upfront price tags on the high end LED lights, plus what appears to be a small savings in electrical usage and then compare that to the much cheaper upfront cost of their HPS setups and then they compare that to their current cost for a grow compared to the return on investment.
But they seem to ignore COBS, which especially in kit form are comparatively priced to the start up cost of an HPS system.
COBs, when run at 75% power will last like 10-15+ years before the lights dims enough to be noticeable, at which point it then becomes a clone light.
These same folks don't typically factor in all the HPS bulbs that will need to be changed in that 10-15 years, every 6 months at $30 a pop..
When I built my last COB light, it was about $100 more than a comparative HPS setup.

Then there is the fact that LED prices keep going down and older tech like vacuum tubes, sorry, HPS light prices will continue to go up as less and less people use them...

I under run the LED's and it should lat me about 10 years, so that's like $35 a year.
Compare that to the initial start up costs of an HPS system and the regular bulb changes and over that same period of time you are looking at the system costing you $70 a year, plus the additional wattage...

Whatever, I know LED's work and I can talk myself blurple in the face trying to convince others of that fact, but if they are set on the fact that HPS works, because it's what they have always known, then no amount of fact or reason will change their minds.
Something will just click one day and they will get it and that's all that matters...

If I were ever to ever go with a bulb type light it would be Light Emitting Plasma, that shit is awesome!!!
A bulb the size of a fat grain of rice can kick the ass of any other light out there!!!
EXCEPT during flower because LEP is a blue spectrum light....
Wa Wa Wa....
Click to expand...
I have a whole closet full of 600 and 1000 watt Hortilux bulbs. Nothing but "clutter" for me. I will most likely never use an HPS again.
LED technology has hit the point of far superiority to HID in most circumstances. It will only get better and better.
Like comparing modern tv to the old "consoles". Led will always have their "doubters" for a while longer.
 
xtsho

xtsho

Well-Known Member
I guess a bunch of people didn't read the entire article.
Johnny Lawrence said:
I replaced 2 600 watt HIDs with 900 watts of cobs and have been nailing the exact same numbers for well over a year now. Pulled a 6 out of a 4x4 and replaced it with 450 watts of PCB/cobs - same thing. I still run a 6/750 DE in my big room, but it has 12 foot ceilings.

I live in an area where electricity is incredibly expensive and heat waves are a common occurrence.
Click to expand...
I wasn't implying that LED's don't grow great weed because they do. I was just pointing out a section of that study that states a more profitable strategy would be to use standard LED flood lights rather than the expensive LED's marketed to cannabis growers.

Where I live we have some of the cheapest power in the United States. So electricity is not a factor. Plus in the winter the heat is welcomed since I grow in an unheated garage. I will probably look into LED's to use during the hottest part of the summer but even then it seems the good LED's still put off a substantial amount of heat. If and when my current equipment fails I'll transition over to LED's. But at this point I see no reason to invest in anything while I still have functional equipment. And regardless of all the "You're living in the past" nonsense because I grow with HPS I'll continue to do so. Not that you have ever made those types of comments but many do. All I know is I'm doing great with my grows and so many others have spent tons of money on the latest LED's, fancy nutrient lines, current fire strains only to end up with crappy grows, crispy leaves covered in all kinds of spots, and posting for help in the marijuana plant problems section.

I'm not talking about you as I know you have awesome grows. I'm referring to the newer growers that went out and bought the most expensive light and then insult others that have been growing for decades because they use HIDs. It's as if some are more concerned about showing off their latest toys instead of focusing on learning how to grow.
 
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