Investing in new lights LED or HID?

[SupraSPL]

What you (and Cree) mean by "efficiency" is not what I mean by efficiency. To Cree efficiency means watts to lumens, ex. "lumens per watt for a white power LED". To me (and photo-botanists) efficiency is really "quantum efficiency" (or relative quantum efficiency). Quantum Efficiency (QE) tells us how efficiently each photon within each wavelength within PAR range can drive photosynthesis. The greater the ability of the photon to drive photosynthesis the greater the QE of that photon's wavelength.

We need to measure the light plants use (PPFD), not the wattage vs the irradiance of light measurement for humans (lumens).

HTH

I agree and think it is important to stress that lumens are only useful when comparing lamp systems with comparable spectral distribution. Many LED manufacturers focus on lumens because it is very useful for the majority of their industry. Luckily we can use lumens to compare one LED to another, thanks to the very similar SPD of various LEDs. When it really comes down to it however, I am relieved when manufacturers measure radiometric output in watts. This makes it very easy to compare radiometric efficiency from one LED to another. It seems like manufacturers are fond of listing radiometric output for blues but sadly they tend to use only lumens for reds and whites.

Secondtry I think I understand better now where you are coming from, growing the plant to its maximum potential. As your sig mentions, LED is probably not as cost effective for that sort of growing goal. But on the other hand, I can hardly think of an indoor situation that is not a power limited environ.

As a student of environmental studies, I have come to believe that we should do everything possible to increase efficiency. Every watt we use from the grid comes at the cost of 3 watts worth of coal heat. Increasing the electric supply is not nearly as desirable as reducing the load. We don't have to make sacrifices to reduce the load, we can get the same job done with less watts and there are many good reasons to attempt to do so.

 

[asde²]

when i said efficiency i OBVIOUSLY meant light output in watts % - a 200lm/w would reach efficiency depending on spd way over 50% (could easily be >65%), cdm-tmw as best hid i know got <45% efficiency!! dont try to make the leds worse than they are but tell people that led arent yet, i like

1100 max because bleeching seems to start at 1000 already and from the beginning of indoor grows, people really fast noticed that too much light doesnt increase productivity/kwh.. imo the whole point about led is finding the perfect spectrum, the combination of wavelenghts giving best results in combination - research example are the metal halide grows with different color temperatures (aka different efficiency, spd and ppf)
lower output but more outcome

 

[B. Friendly]

check these new babies out SULFUR PLASMA lighting, kinda pricey but wow.
http://www.icmag.com/ic/showthread.php?t=163137

 

[secondtry]

Hello SSPL,

2ndtry wrote:

What you (and Cree) mean by "efficiency" is not what I mean by efficiency. To Cree efficiency means watts to lumens, ex. "lumens per watt for a white power LED". To me (and photo-botanists) efficiency is really "quantum efficiency" (or relative quantum efficiency). Quantum Efficiency (QE) tells us how efficiently each photon within each wavelength within PAR range can drive photosynthesis. The greater the ability of the photon to drive photosynthesis the greater the QE of that photon's wavelength.

We need to measure the light plants use (PPFD), not the wattage vs the irradiance of light measurement for humans (lumens).

HTH

I agree and think it is important to stress that lumens are only useful when comparing lamp systems with comparable spectral distribution. Many LED manufacturers focus on lumens because it is very useful for the majority of their industry. Luckily we can use lumens to compare one LED to another, thanks to the very similar SPD of various LEDs.

The question about the amount of light plants use for most Pn (ie. PAR range) is still not answered with lumens tho. All lumnes will tell you is how efficient the LED is in converting watts to lumen, a much better qualification is watts to PPFD, but both should be reported by distance. However, in terms of irradiance for plants we would still need to use PPFD from a quantum sensor when comparing LED arrays with the similar SPDs (even if the SPD reports irradiance by PPFD) so the LED arrays can be tested from different heights.

SSPL wrote:

When it really comes down to it however, I am relieved when manufacturers measure radiometric output in watts. This makes it very easy to compare radiometric efficiency from one LED to another. It seems like manufacturers are fond of listing radiometric output for blues but sadly they tend to use only lumens for reds and whites.

Yea that's great for maximizing power use efficiency by limiting power consumption, but watt to PPFD would be more useful. PPFD is needed for irradiance at canopy, PPFD weighted with QE per wavelength.

SSPL wrote:

Secondtry I think I understand better now where you are coming from, growing the plant to its maximum potential. As your sig mentions, LED is probably not as cost effective for that sort of growing goal. But on the other hand, I can hardly think of an indoor situation that is not a power limited environ.

I was referring to outer space (NASA) in terms of power-limited environ, that is where the idea of using LED arrays came from AFAIK.

SSPL wrote:

As a student of environmental studies, I have come to believe that we should do everything possible to increase efficiency. Every watt we use from the grid comes at the cost of 3 watts worth of coal heat. Increasing the electric supply is not nearly as desirable as reducing the load. We don't have to make sacrifices to reduce the load, we can get the same job done with less watts and there are many good reasons to attempt to do so.

I fully agree. That is why I buy new HID lamps each grow and use a good digital ballast (a NextGen). However, like I wrote to Mad.L, to me the best way to increase efficiency is to use a HID and grow with ideal conditions (much of which I wrote about in this thread) to yield a large quantity of cannabis (many pounds from one grow). That way you could match in a few grows what it takes a whole year of LED growing to produce (I assume). Thus you could only grow say 6-10 months a year, cutting energy cost over a year. By using that method the quality should also increase (if you are using only 300-400 PPFD).

How did you measure the PPFD? And do you know why Knna suggsets 300-400 PPFD? (I could not find his references or reasoning on that topic)


Thanks

 

[mad librettist]

I don't understand the rest of your post, re: what you trying to get at with diminishing returns? Did you read my responses to SSPL already?

2nd,

I was basically asking if what you meant is that your answer is justified because we are still getting a good return. sorry round about way of agreeing with you kinda convoluted in retrospect. I was very stoned off my can't flower light weed. (I agree though for the power invested the return is low)

 

[secondtry]

Hey Asde,

when i said efficiency i OBVIOUSLY meant light output in watts % - a 200lm/w would reach efficiency depending on spd way over 50% (could easily be >65%), cdm-tmw as best hid i know got <45% efficiency!! dont try to make the leds worse than they are but tell people that led arent yet, i like

Well it wasn't obvious to SSPL and myself. Could you please define what you mean by efficiency? And could you please tell us how you found the efficiency? I see you are using lumen/m^2 but I am not sure why think that is a good thing to do (we should be using umol/m^2/sec).

Asde wrote:

1100 max because bleeching seems to start at 1000 already and from the beginning of indoor grows,

What type of plant was the bleaching experienced? Do you know how the PPFD was measured? And do you know the daylength (hours of light)? Can you post the references for that info so I can read more?

What do you mean by "from the beginning"? If you mean when the plants are young (seedlings) then I agree. The high irradiance is for veg and flowing.

As the four studies I uploaded found, 1,300-1,500 PPFD is ideal for cannabis rate of Pn, Water Use Efficiency (WUE), Co2 assimilation, growth and yield. In the summer near noon the irradiance is around 2,000 PPFD (depending upon latitude). We are giving plants much less irradiance than they would get outside for a few hours around noon by using 1,300-1,500 PPFD.

Asde wrote:

people really fast noticed that too much light doesnt increase productivity/kwh.. imo the whole point about led is finding the perfect spectrum, the combination of wavelenghts giving best results in combination

I treid to expain in this thread why spectral quality (SPD) is not as important as irradiance (PPFD). Especially considering the info about spectral quality is not correct (see the info about green photons driving Pn more than red and how K.McCree's QE was updated). It sound like you use Knna's spreadsheet?

 

[HydroManiac]

I used to work at a place that sold lots of ballasts and lightbulbs and I was the person that was doing much of the led stuff. In my opinion led's are not really there 100% and I think the prices for them wil go down a lot and they will get a lot better then they are now so I would wait before I would get led's

 

[secondtry]

check these new babies out SULFUR PLASMA lighting, kinda pricey but wow.
http://www.icmag.com/ic/showthread.php?t=163137

Wow! They have really come a long way. That looks great. I didn't read past the home page yet (link), I will read your thread now. That 1,000w lamp looks interesting so far. I like the SPD, however, more red would be nice but it is still a good SPD. One thing to point out is the energy from blue photons which do not generate photosynthesis is turned into heat, thus higher blue can equate to higher leaf temp (vs. higher red). All in all, I like the SPD of the Hortilux Blue more than the SPD of that lamp. But I really like other aspects of that lamp...

On point I like is that the lamp can be dimmed up to 15% without effecting the spectral quality. That is a great feature I have wanted because starting the plant's day with lower irradiance allows the plant to reach steady state of photosynthesis faster then blasting the plant with full irradiance right when it 'wakes up'. I am going to get those lamps if they look good and test them for sure.

Thanks.

 

[asde²]

umm i thought it was clear;
lets example:
energy input 100w, light output 35w -> efficiency 35%

the bleaching happened to several strains, and yes i know the tops may recieved more photons but as you seem to noticed already, thats nothing we can deal with, we cant place hid's between the plants and lower wattage as efficiency decreases and heat gonna kill em.. but hanging 2x400w hps over 1.2m² is not giving much more than using just a 600w and gpw wisely the 600w gonna win even when bringing in the higher efficiency.

you sayin spd aint that important.. it depends on which face you watch, the good spd can beat the bad spd with less ppf - not 400%+ as advertised from horti led sellers but yes we all know they go ridiculous sometimes..

 

[secondtry]

B. Freindtly wrote:

Although it will cost $3,500 per 1000w.

Whoa, never mind! haha. Man that is expensive considering the SPD of the Hortilux Blue is better than the SP of the of plasma and a 1,000 Hortilux Blue lamp, PL reflector and NextGen ballast is only about $600-700. Hell, toss in a LightRail 3.5 for about $300 and a 6" in-line fan for about $200 for a grand total of about $1,200. And a grower has money left over to put in Co2 tank/emiiter for about $300 and auto-Co2 control for about $350.

Thanks

 

[secondtry]

umm i thought it was clear;
lets example:
energy input 100w, light output 35w -> efficiency 35%

That kind of qualification is not about growing the plant, it's more about efficient use of power. Thus it's not a factor when deciding between lights unless one wants to consider the cost of the lamp in relation to it's output in human eye spectra.

Asde wrote:

the bleaching happened to several strains, and yes i know the tops may recieved more photons but as you seem to noticed already, thats nothing we can deal with,

You are claiming this with cannabis? There are two main reasons for leaf bleaching: photoinhibition (from long time light saturation) and daily light integral. But it also has to due with the VPD (Vapor Pressure Deficit) of the leaf which is effected by temperature, leaf temperature and humidity. High VPD is not good and it is very common, it's not really scientifically sound to make a judgment about the effects of light irradiance without quantifying other variables.

It sounds like you didn't find PPFD. Did you use a quantum sensor or spectroradiometer? If not how can you claim 1,100 PPFD as the light saturation point?

Asde wrote:

we cant place hid's between the plants

True. But that doesn't mean irradiance is not important, nor that PPFD of 1,300-1,500 is not ideal. To maximize light penetration use a lamp with high levels of green in SPD and calculate the plant "Leaf Area Index" (LAI). Using LAI you can find "PPFDi" which takes into consideration the PPFD intraconapy, thus we can find PPFDi of X Leaf Area Index when PPFD is 1,300 (for example). That way we can map the whole canopy and more efficiently use the lamp thus increasing the wattage efficiency by using LST, leaf trimming, etc.

Asde wrote:

you sayin spd aint that important..

No I am not, "that important" is too relative. I am saying SPD is less important than PPFD as long as the SPD is what we commonly use to grow plants. This is important for cannabis in three ways: 1) we know what PPFD offers peak Pn, growth and yield of cananbis; 2) we do not know what SPD is ideal for cannabis because the PAS (Photosynthesis Action Spectra; from K.McCree) is not specific to cannabis; and 3) the currently accepted PAS is not accurate for high irradiance HID, it is however accurate for LED, thus for the PAS to be of use it has to be modified for HID QE (Quantum Efficiency; from green light). What that means is PPFD should be used for now when comparing lamps to grow cannabis (assuming both SPD's are the normal kind used to grow plants), it is the only qualification offering solid scientific proof on cannabis, SPD and PAS are not accurate to HID nor cannabis (respectively).

 

[asde²]

bring some some self theoretical points.. we dont know best spd for cannabis but we know that white light (high cri) is for sure not the best

i made diagrams of spd calculations myself and for this point, im beyond mccree as his researches are too plain and well.. he is gettin old lol
seriously, basing your setup on researchs made for leaf plants is not what you want for cannabis

 

[secondtry]

I think I know who you are, was your nik "LED Developer" before? I remember that guy made his own diagrams too. His diagram gave blue light the same QE (Quantum Efficiency) as red light and that is not correct. His diagram gave very little (or no) QE to green! Not only that but his diagram used relative terms like "low" and "high" without quantitation.

If you didn't measure PPFD yourself, or can not show how it was measured than what you claim is not valid. You are beyond McCree? How is that? He used monochromatic lighting to make his PAS which shows the QE (Quantum Efficiency) of wavelengths by their effect upon Pn (rate of photosynthesis). And the PAS of most higher plants (cannabis included) are similar, thus we can use PAS for cannabis. Due to the lighting McCree used when finding QE it means PAS is more accurate for LED then HID. That is why I state the PAS needs to be modified for HID. And the PAS of cannabis will be a bit different than that which McCree created...but nothing like what LED Developer dreamed up...

 

[asde²]

holy shit man im not led developer, im asde² former asde.
im the guy who was banned for stating reality in led sponsored thread.. but in the end, my diagram give very little to green too! im not looking for power by wavelength but combination of wavelength to optimize the output!!
most researches (all?) are based on total irridiance and not on a combination of wavelenghts thats why i dont accept.. to be precious we need more research and thats for now the only real way to deliver facts, but limited sources hinder us for now but that shouldnt be a big problem, im absolutely understanding your point so offense directed to me considering i dont know shit, please stop that! but im trying to investigate the science from another (in my opinion, based more efficient) point of view
another research example are for sure led grows while base efficiency and ppf stays unknown, from experience we know led efficiency is crap and if the gpw results aint fake (talking about serious looking ones, 2+ gpw with <20% is ridiculous) some results still showing that with less ppfd the results can be better than with higher ppfd by changing spd.

please dont deny the facts, there are a dozen of researchs showing the increase of yield depending on spd and not just quantum efficiency - considering light sources overall have a bad spd efficiency the ppfd for sure is the good measurement, but only that.

 

[secondtry]

@ All,

For those using LED due to issues about the impact of HID (high wattage) upon the environment why not become carbon natural, or better yet carbon negative in terms of the carbon footprint of your grow by purchasing carbon credits?

I use TerraPass for my car:
http://www.terrapass.com/about/

 

[secondtry]

@ Aside,

I still think your LED Developer and I can see why you were banned from the LED forum. Your perversion and misunderstanding of this science is as astounding as your insistence in-spite of your ignorance.

Three reasons why I will ignore you from now on:

1. I think you are LED Developer

2. You have yet to provide one reference for your claims, nor info on how you found 1,100 PPFD. LED Developer acted the same way when I asked him to tell me how he found the rate of photosynthesis of cannabis to make his diagram.

3. You think by adding green light you are not optimizing wavelengths in a synergistic fashion. See the study funded by the Kennedy Research/Space Center in my big post on page one for info on green LEDs in a LED array.
​

Goodby

 

[renz]

So I'm confused does secondtry have an optimal spectrum profile for cannabis...

Or is this RQE profile meant to be a general standard relative to all plants, in order to provide a way to characterize lights for general purpose plant lighting? Because if it's not cannabis specific, it would be safe to assume that within the whole realm of the plant community, plants in all their variety would have different absorption capabilities from one another.

Given that cannabis is known for being exceptional in its weed like growth compared to all of plant life in general, isn't it safe to assume that its optimal spectrum differs from an industry meter stick for measuring light in a consistent manner?

Because I looked at those plots secondtry posted and HPS/MH profiles look *nothing* like the RQE. Yet with some normal or warm white LEDs, and also amber and reds, you could probably mimick the profile almost perfectly.

But how do we know this is the profile that actually works for cannabis, though? Is it an average of all plants? Certain plants?

Dismissing SPM as less important when the primary advantage of LEDs vs HID is very narrow bandwidth output capabilities at probably dozens of frequencies just seems unscientific.

Because really, getting the right amplitude is easy once you know the spectrum. So all this talk about the right absolute power level seems kinda one sided.

 

[mad librettist]

Given that cannabis is known for being exceptional in its weed like growth compared to all of plant life in general,

well, I'd say this isn't true. Mile a minute weed, kudzu, japanese knotweed, sumac, and the list goes on of truly fast weedy plants. And then there is bamboo. Now that is fast! I'd say cannabis is average to fast. I know we call it weed, but I wouldn't classify it as a weed, which is a fast growing plant that likes very bacterial soil that makes lots of seeds that travel far and wide.

How different are the optimal spectra is the sticking point I guess. They can fail to be significantly different while still being different.

 

[SupraSPL]

Hello SSPL,
All lumnes will tell you is how efficient the LED is in converting watts to lumen, a much better qualification is watts to PPFD,

I agree. I only use lumens to compare the relative output of similar bulbs.

Yea that's great for maximizing power use efficiency by limiting power consumption, but watt to PPFD would be more useful. PPFD is needed for irradiance at canopy, PPFD weighted with QE per wavelength.

I agree here too, except I think we should examine both PPFD and PPFD weighted, as QY is mostly an educated guess?

Thus you could only grow say 6-10 months a year, cutting energy cost over a year. By using that method the quality should also increase (if you are using only 300-400 PPFD).

When considering overall watts burned/yield, I aim to significantly outyield the most efficient HIDs available (600watters). I intend to take flowering time into account of course. I also intend to take vegetative stage into account. This can be done either on a small scale or a large scale. That is part of the beauty of it in my opinion.

With all that said, I am not always a yield-hound. I am talking in relative terms only. Maybe a variety of Thai Skunk yields .5 gr/watt for me in soil with 600w fancy HID. In that case I want to see .75 gr/watt with same cut using say 14 watts of LED. If I cannot make that happen I will be confounded

I do not suspect a sacrifice in quality. I have smoked CFL bud, plain HPS bud, outdoor bud and LED bud. All have got the job done and done well so far. Even more reassuring, every single homegrown bud I have smoked has been preferable in smoothness and flavor when compared to commercially available bud.

How did you measure the PPFD?

KNNA has secured known bins of Golden Dragon Plus and provided ue/w data. Using these known bins at predetermined current output levels, he suggests 28-33 watts of dissipation per square foot, and we are talking short plants of course (~18 inch tall canopy). I am not using lenses so the lamp will be 2-6" from canopy. Here is the data I am working with:

- Red bin JX
640nm (638-642nm peak)
@ 600mA, 2.34V, 1.63µE, 1.4W (1.16 µE/W)

- Coolwhite bin KZ
Tone 6Q (6200-6400K)
@ 700mA, 3.46V, 2.05µE, 2.422W (0.85µE/W)

- Royal Blue bin 1U
450nm (449-453nm peak)
@ 700mA, 3.42V, 2.6µE, 2.395W (1.09 µE/W)

my math:
64 reds - 104.3µE
14 white - 28.7µE
7 blues - 18.2µE

Total 151.2µE covering 4 sq ft
340µE/m2 +/-7% manufacturer allowance

And do you know why Knna suggsets 300-400 PPFD? (I could not find his references or reasoning on that topic)

KNNA addressed the issue on CC.net here. This post (#21) is from 2006 where he discusses the theory that maximum photosythetic efficiency occurs at lower irradiances. Here is some info he posted in 2009 regarding his spreadsheet and light measurement techniques. He also describes some of the things you have mentioned, such as the importance of using ue vs par and the surprising usefulness of green photons.

By the way, thanks for all information and links you have posted. I have learned a lot already and I intend to look them over more thoroughly.

KNNA and the spanish team have been experimenting with varying SPD quite a bit. I am reasonbly sure that I saw tests where white LEDs were used exclusively and the results were inferior to red tuned spectrums. I will try to dig that info up.

 

[mad librettist]

also why assume the optimal spectrum is constant throughout the life of a plant.