LED Lab 2009

[knna]

Nice thread about the LED light, although to much red is used according to this
schedule of the agricultural university of Wageningen

Translation
Golflengte = wavelength
blauw=blue
rood=red
verrood=farred
bloei korte dagplanten=flower shortday plants
stimulerend=stimulating
remmend=inhibited

Namaste

We need more concrete info about cannabis responses than general summaries.

We are trying to find the best spectrum distribution for cannabis, and identify the possible trade offs of using some spectrum distributions vs others distributions.

And its a matter of experimenting to quantify, so we can select the best balance for our targets.

For example, about the amount of red in the spectrum distribution: how much it enhances photosynthesis? how much longer it does blomming? Is the cannabis response linear to such parameters, or behalf by sudden steps?

Thats the only way to decide if using 20, 40 60 or 80% red of the total spectrum.

 

[LeoRexTyrannus]

Found this on Wikipedia, since it applies, I thought I'd bring it to your attention.

"A new technique developed by Michael Bowers, a graduate student at Vanderbilt University in Nashville, involves coating a blue LED with quantum dots that glow white in response to the blue light from the LED. This technique produces a warm, yellowish-white light similar to that produced by incandescent bulbs. Quantum dots are semiconductor nanocrystals that possess unique optical properties. Their emission color can be tuned from the visible throughout the infrared spectrum. This allows quantum dot LEDs to create almost any color on the CIE diagram. This provides more color options and better color rendering white LEDs. Quantum dot LEDs are available in the same package types as traditional phosphor based LEDs."

Also I found a research paper by several Oxford departments where they claim to have found the the optimum energy level for maximum chlorophyll production for mass production, sounds like a god send to the medical community if it's true.

http://www.springerlink.com/content/a3527u6018823x43/

Btw hello Weezard and Knna, glad to see you and everyone else still researching. I remember well over a year ago when was doing my first crop with a 45W LED panel and the things you guys told me let me know LED is the future, amazing to see the advancements that have been made, the various and numbered high powered systems available on the retail market right now, simply bravo everyone. This research will allow medical patients in chronic pain the ability to grow with a level of confidence and a relief on their wallet in the long term and a boon to their spirit in the short.

Well that's enough with my pie in the sky but mark my words its the future of this.

 

[billyjojimbob11]

Yea, I am still waiting on Cree to release a quantum dotted emitter in various whites and reds. Maybe next year.

 

[Tim_in_marin]

My LED test - 2009 using LumiGrow lights

My LED test - 2009 using LumiGrow lights

So in my initial tests, it seems that the LED's are great for veg, everyone seems to agree on that...


For flowering, there are challenges.....

For the first test, I pitched about 500 watts of LED power against a 1000 watt HPS ( 2 lumigrow 250 watt devices ). At the end of that test, the LED light produced high quality results, but at a level to what I would expect out of a 600 watt HPS.

On the plus side:
no cooling costs. heat output was less than even a vented HPS system
I used 1/2 the water and nutrients.
Nice quality results.

cons:
low yield

hmmmm.... why?
I have three possible theories, all of which can be tested (assuming no mistakes in the actual grow methods were made ) .

1. The LED grow light i used has blue and Red LED's only. Par light measurements include some green and yellow, perhaps plants need *some* light in the middle part of the PAR range after all....

2. just not enough light is produced. This seems unlikely, as all 250 watts of light of the LEd light are in the PAR range, an HPS wastes 90% of it's power producing heat and light that plants do not use.

3. Something missing from the far red portion of the spectrum, or at the other end, from the UV portion of the spectrum.

So.... new tests proposed....

test 1: 4x4 table with two the same two LED lights, but with the addition of a 125 watt CFL. I got this idea from my grow shop. Apparently the lumigrow sales person was there and talking about "hybrid" systems. This means mixing an LED with another type of light source. they claimed that it was the way to go if you wanted to really maximize your yield.

test 2: buy two more lights and test 1000 watts of LED versus 1000 watt HPS. anyone wanna contribute ? cannot really afford that test....

test 3:
I have read posts that suggest that there needs to be a little far red (>700 nm ) in the mix in order to properly reset the Pr to Pfr photoperiod response mechanism in short day plants. This could be causing issues with the flowering. So, I propose a test that includes the addition of far red. Looks like a plain ol ordinary incandescent bulb will do as good a job of producing that part of the spectrum as an HPS light.

at the other end of the spectrum is UV, however HPS lights do not produce UV. While UV may have some benefit, since it is not produced by the HPS, I am not going to worry about it for this test.


So, open to hear thoughts and comments as to how I should procede for the next round of tests.

 

[knna]

So in my initial tests, it seems that the LED's are great for veg, everyone seems to agree on that...


For flowering, there are challenges.....

For the first test, I pitched about 500 watts of LED power against a 1000 watt HPS ( 2 lumigrow 250 watt devices ). At the end of that test, the LED light produced high quality results, but at a level to what I would expect out of a 600 watt HPS.

On the plus side:
no cooling costs. heat output was less than even a vented HPS system
I used 1/2 the water and nutrients.
Nice quality results.

cons:
low yield

hmmmm.... why?
I have three possible theories, all of which can be tested (assuming no mistakes in the actual grow methods were made ) .

1. The LED grow light i used has blue and Red LED's only. Par light measurements include some green and yellow, perhaps plants need *some* light in the middle part of the PAR range after all....

Hi, Tim, im glad to find seriously testing LED grows and wondering how to improve them.

This first hipothesis has been discussed previously in this thread, i believe.

Ive researched botany literature about it, and it seems most species needs a more complete spectrum, and only a little grows the best with just red or red plus blue. For our experiments, it seems cannabis may grow perfectly with red and blue alone during vegging, but that spectrum results on reduced yield during blooming.

IMHO, we must find how much of other wavelenght we should add, instead of wondering if there is a need to add anything. We must try to find the spectrum distribution that produces more for each mol of photons and discover if there are effects over quality to take in mind.

2. just not enough light is produced. This seems unlikely, as all 250 watts of light of the LEd light are in the PAR range, an HPS wastes 90% of it's power producing heat and light that plants do not use.

Its not unlikely, but the most probable cause (again, IMHO).

Watts burned gives a very good reference of light delivered for HID lamps, due the ratio of light emitted/watts burned is almost constant for them.

But it not happen with LEDs. There are huge differences on efficiency between LEDs. From 5 to 40%, meaning up to 8x more light emitted for each watt burned. And differences of about 200% (half light per watt burned) are pretty common.

Not only for the LED model, but most of them have flux bins starting at half the light emitted of the upper bin. Current used affects a lot efficiency aswell: a LED running at 350mA with 30% efficiency runs way below 20% at 1A (so, less than half the light emitted per watt burned). Mounting technique and thermal dissipation design has a strong effect too.

We need to quantify how much light we are using if we want to get any conclusion for our experiments, as im repeating since this thread started.

3. Something missing from the far red portion of the spectrum, or at the other end, from the UV portion of the spectrum.

Although far red has strong effects on morphology and other biological reactions, it is unlikely that photosynthetic efficacy drops too much for their lack. Maybe a total ausence of far red, yes, but generally due to shadowing producing far red, a complete lack of far red is rare.

Most growing spectrums are caracterized by their low far red content, and that includes HPS, MH and fluorescents. Maybe far red is required, or at least is required on certain stages as flowering induction and rippening, but on any case, on low amounts.

So.... new tests proposed....

test 1: 4x4 table with two the same two LED lights, but with the addition of a 125 watt CFL. I got this idea from my grow shop. Apparently the lumigrow sales person was there and talking about "hybrid" systems. This means mixing an LED with another type of light source. they claimed that it was the way to go if you wanted to really maximize your yield.

Hybrid systems are the best way of building a cost effective LED setup currently. Mix of fluorescents (either tubes or CFLs) are proving to work great while strongly dropping the cost.

I advice to go this way to the people who just want to grow with LEDs sucessfully, as it avoid the problem of spectral lackings and reduces costs, while keep the system very easy to cool and reduces initial cost.

But for research, when using a broad spectrum white source is very difficult to study the effect of isolated wavelenghts and the best ratios for each wavelenght.

test 2: buy two more lights and test 1000 watts of LED versus 1000 watt HPS. anyone wanna contribute ? cannot really afford that test....

Really i dont see the need of getting 2 more lamps. Average light density (light emitted/ surface or volume of the grow) is what matter. Use the 2 LED lamps on half the grow space than the 1000w HPS so you can compare results.

test 3:
I have read posts that suggest that there needs to be a little far red (>700 nm ) in the mix in order to properly reset the Pr to Pfr photoperiod response mechanism in short day plants. This could be causing issues with the flowering. So, I propose a test that includes the addition of far red. Looks like a plain ol ordinary incandescent bulb will do as good a job of producing that part of the spectrum as an HPS light.

Incandescent bulbs has a phytochrome photoequilibrium about 0.22-0.25, while HPS and most MH are 0.82-0.86 and red/blue LED lamps about 0.87. A simple incandescent bulb and the end of the light on cycle is able to strongly drops phytochrome equilibrium below of outdoor conditions. Halogen spots avoids reflectors and allows to give the far red from a small source on the grow, that not disturb other lamps operation.

at the other end of the spectrum is UV, however HPS lights do not produce UV. While UV may have some benefit, since it is not produced by the HPS, I am not going to worry about it for this test.


So, open to hear thoughts and comments as to how I should procede for the next round of tests.

Fully agree. There is a lot of discussion about the use of UV, but if we can be sure of one thing about it is that UV is not required. It it enhances terpenes or cannabinoids production is another question, but for sure we arnt obligued to use them.

My suggestion is to measure light emission or at least, light density produced by the LEDs lamps before doing anything.

All the best,
knna

 

[knna]

Also I found a research paper by several Oxford departments where they claim to have found the the optimum energy level for maximum chlorophyll production for mass production, sounds like a god send to the medical community if it's true.

http://www.springerlink.com/content/a3527u6018823x43/

Btw hello Weezard and Knna, glad to see you and everyone else still researching. I remember well over a year ago when was doing my first crop with a 45W LED panel and the things you guys told me let me know LED is the future, amazing to see the advancements that have been made, the various and numbered high powered systems available on the retail market right now, simply bravo everyone. This research will allow medical patients in chronic pain the ability to grow with a level of confidence and a relief on their wallet in the long term and a boon to their spirit in the short.

Well that's enough with my pie in the sky but mark my words its the future of this.

Glad to see to still are growing with LEDs.

Excelent article, the best ive read about cannabis growing on years. Thanks a lot for sharing the link.

I still miss a study of same parameters after long term acclimatation to each conditions, but finally we have the long required data about WUE, E, g, Ci/Ca, P(N) of cannabis at different irradiaces and CO2 levels.

I cant agree with some conclusions from the presented data, but anyway that article is pure gold.

 

[geekusa]

Can anyone give a recommendation on these new units from HTG?

Could the 120W be used to grow around 5 plants?

http://htgsupply.com/viewproduct.asp?productID=53987

 

[billyjojimbob11]

I think I mostly agree with Knna. There is no doubt that far red helps, but you dont need much IMO, the plant uses this energy primarily as floral signals. I have found that with warm white leds and even "Neutral White", you will get a descent amount of far red, possibly enough to complete the red spectrum floral chain.

Basically what I am trying now is

1. Best possible leds on the market in the highest quality control bins. (Cree, Phillips, Osram, Optek etc.)
2. Broad sprectrum yellow/orange/red (the most efficient ratio's (still unknown)
3. Warm white/Neutral White for all missing red colors and even some missing blue and green.
4. Most efficient led culminating lenses at the correct angles.


In 5 weeks I will be able to give my results, so far, the results look promising, and 2 weeks ahead of my previous led grow in size and maturity.

 

[nekoloving]

I think I mostly agree with Knna. There is no doubt that far red helps, but you dont need much IMO, the plant uses this energy primarily as floral signals. I have found that with warm white leds and even "Neutral White", you will get a descent amount of far red, possibly enough to complete the red spectrum floral chain.

Basically what I am trying now is

1. Best possible leds on the market in the highest quality control bins. (Cree, Phillips, Osram, Optek etc.)
2. Broad sprectrum yellow/orange/red (the most efficient ratio's (still unknown)
3. Warm white/Neutral White for all missing red colors and even some missing blue and green.
4. Most efficient led culminating lenses at the correct angles.


In 5 weeks I will be able to give my results, so far, the results look promising, and 2 weeks ahead of my previous led grow in size and maturity.

sweet! any pix?

 

[Tim_in_marin]

Knna,
Thanks for your post. Frankly, I have been reading your posts for a year or two now and your research has been extremely helpful to me.
In terms of the next tests to run, I agree that it is a good idea to understand exactly what is needed by the plant. another way to think of it though, is to understand exactly what is produced by an HPS bulb. I came across some studies by Gerald F. Deitzer from the university of Maryland that were interesting. here is a link:
http://ncr101.montana.edu/Light1994Conf/Contents.htm
I was able to download an excel spreadsheet that had spectral values for a number of different lights.
I also found some spectral data for the red LED that is used by the Lumigrow light. I will try to get it uploaded. it is pretty interesting. I think that it might be a good starting point for figuring out the power and capabilities of the lights. It looks to me llike the data is in milliwatts per nanometer, so I believe we will have to convert it to micromoles. This is where we get to play around with plancks constant and avagadro's number. I have started on a conversion spreadsheet. not sure if the numbers are correct just yet....

 

[Weezard]

Rare as hen's teeth, they are.

Rare as hen's teeth, they are.

Wish I could help with that.
Can't recall seeing any, must be new, yah?:wink:

I'll keep lookin', just in case.

Weeze.

 

[LeoRexTyrannus]

Glad to see to still are growing with LEDs. Excelent article, the best ive read about cannabis growing on years. Thanks a lot for sharing the link.

Absolutely no problem Knna, honestly I'm using CMH for flower but I will never give up my active interest in LED. It's clearly the replacement for HID undoubtably, especially in light of SMART GRID techonology soon to be rolled out nationwide (US here).

I'm glad you could make sense of the research data, it was over my head, but if it eventually helps one terminally ill person to grow some optimum quality medicine, then I'm happy to have done the leg work.


To the gentlemen that did 500W LED vs 1000W HID (Sry, forgot name, don't want to go back and rewrite this to grab your name sir.)

As far as I know sir the only commercial LED system available verified to produce at a comparable level to its advertised HID alternatives are the TI SmartLamp and SmartBars, I've actually seen grow tests that positively indicate it fully yeilds according to their claims.

I will be following the discussion as close as a layman is capable. Keep up the good work.

 

[Tim_in_marin]

Hi LeoRex,

I would love to see some links to successful grows with the TI products. I have had a difficult time finding info about them. I saw a tomato test on greenpinelane, but that is it. I swear, it seems like they do not actually sell the light. I have tried to find one locally ( northern california ) but no one I know anyone who has ever actually seen one. There is a website, grow revolution, where you can supposedly buy it online. I clicked the "buy now" button and it resulted in a broken paypal link.

Paypal? If these guys were serious about selling online, they would have a real "shopping basket" connected to a real merchant account, and not some cheesy paypal account.
I talked with a grow shop owner and he said that he once got a call from a TI salesman but that the person would not provide any demonstrations and wanted to just sell it outright. The shop owner also said he heard that Theoreme was in bad financial shape. Just a rumor, but hey, enough of this sort of thing and one begins to wonder....

 

[LeoRexTyrannus]

Now I wait for the 100W. Reds and blues.

These extremely high powered LEDs are fantastic news, I remember having discussions with Weezard about the benefits of discrete high powered LEDs vs. low wattages. The higher wattages have much greater penetration, and the ability to use so few to build a complete and simplified system will reduce costs in the long run. Having such a heat generating yet small package will call for cooling, but the design will make this simple with heat pipes, fans, striling engines, and water cooling available. Finally it should be possible within a very simple design to eclipse HID with a very simple and effective design perfect for mass production.

Weezard, can’t wait to see what you do with these my esteemed tinkerer.

 

[whiskeytango420]

Well if you got Knna and Weez giving you pointers, you cant go wrong man! Those two helped me A LOT when doing my LED experiments! Keep it up!
Experimentation is the essence of science!
good vibes

 

[knna]

Knna,
Thanks for your post. Frankly, I have been reading your posts for a year or two now and your research has been extremely helpful to me.
In terms of the next tests to run, I agree that it is a good idea to understand exactly what is needed by the plant. another way to think of it though, is to understand exactly what is produced by an HPS bulb. I came across some studies by Gerald F. Deitzer from the university of Maryland that were interesting. here is a link:
http://ncr101.montana.edu/Light1994Conf/Contents.htm
I was able to download an excel spreadsheet that had spectral values for a number of different lights.
I also found some spectral data for the red LED that is used by the Lumigrow light. I will try to get it uploaded. it is pretty interesting. I think that it might be a good starting point for figuring out the power and capabilities of the lights. It looks to me llike the data is in milliwatts per nanometer, so I believe we will have to convert it to micromoles. This is where we get to play around with plancks constant and avagadro's number. I have started on a conversion spreadsheet. not sure if the numbers are correct just yet....

I already did a excel spreadsheet that do those conversions, and much more. Its here: http://www.gardenscure.com/420/lighting/117933-bulb-analyzer-tool-actualized.html#post1132481

You can get the conversion factors from it and do your own spreadsheed for what exactly you want (i let all conversion factor open) or use the spreadsheet as it comes. Its designed to analyze growing lamps from its Spectral Power Distribution and lm output.

Im working now developing a "poor's man" spectroradiometer with accuracy enough. Im working on two alternatives ways:1- an small circuit board acting as a quantum meter (and CO2 monitor) and 2- obtaining SPD of light sources using cheap materials: an astronomy spectroscope (often below 20$) or a DIY one (you know, the typical of classrooms, a box and a old CD) and sofware to convert it to a graph on mW (y axis) vs wavelength (x axis), able to analyze it with the Excel spreadsheet, so you can measure lux (or fc) with a simple light meter and automatically convert it to optical watts or uE (apart of many other things).

This cheap spectrometer should serve us to measure actual wavelenght peak of our LEDs aswell as its change with heating (that allows to calculate the thermal resistance junction-ambient air of the setup).

My next step would be to develop a complete poor's man spectroradiometer by adding a DIY integrating sphere.

I hope to have finished the second way on about two weeks, except for the integrating sphere. I really dont need it as i work with LEDs that have their luminous flux very well caracterized.

 

[LeoRexTyrannus]

To me LED look really cool but whats the point?

HPS are almost 1/2 as cheap and grow faster and better plants, thats just my opinion.

The point is Smart Grid is coming, and soon they will be aggregating our power usuage records at a federal level. That isn't paranoia, it isn't a conspiracy, it's a simple fact of the American power grid. LEDs high intial cost isn't going to be a barrier when the alternative is far more risky. This need will drive the LED horticultural industery.

So while HID is working right now, will you want to be sucking up all that juice when they can querie the system for every user with spikes of 400,600, 1000 watts, etc for durations of 12, 14, 16, 18 hours. It isn't enough for a warrant but its certainly enough for an investigation.

There's also the issue of medical patients that need to cut costs on their medicine while using less energy. I could imagine once LED is ready for prime time a non profit charitable organization that would donate LED units to those in need, for their sheer benefit in their time of pain and agony.

HID might be fine for the commercial grower, but it's an enemy to the victims that need access to affordable medicine. This is what must be understood about LED and HID.

 

[Weezard]

Woops! Went and got myself "esteemed"

Woops! Went and got myself "esteemed"

"Weezard, can’t wait to see what you do with these my esteemed tinkerer. "

Thanks kinglizard cop.


Well, if ya can't wait, ya can't wait.
So, here's da latest beastie;




[/ATTACH]

Doing a tutorial build at cdot, by request.

Not sure why.
Leds are so simple your average english schoolboy could slap one together in an hour or so.

Takes me a tad longer and I get too focussed to teach anyone anything.
I just dive in and thrash about, oblivious to time and tide and lunch.
When I re-enter the "realworld" some hours later I am usually pleased by what seems to have magically appeared along with a godawful mess on my bench.
So my "tutorial" consists of before and after pictures and some scribblings as I try, in vain, to figure out what I did and why.

There's pearls and acorns everywhere.
Weeze (Da blind pua'a)

 

[Weezard]

Zachary!

Zachary!

"HID might be fine for the commercial grower, but it's an enemy to the victims that need access to affordable medicine. This is what must be understood about LED and HID. "

Legality is not a problem for me, though LTR makes a good point.
But, anti-social in-security is a very real problem 'roun' here.

Growin' in the free tropical sun, feeds the bugs and the "rustlers". (long, sad, story)

A 1Kw. HID for bloom and a 400W. MH for veg.
will cost about $ 3200.00 per year at our current rate for electricity!
No can!

My LEDs run about $500 per year and there's no bulb replacements every year.
So IF, I could afford a Theoreme, or 4 Procyons, I'd still amortize in less than a year. Then "coast" for the next 4 years.

I'm trying to outdo HIDs just because some folks say it can't be done.

That, and it keeps me out of the pool hall.

Aloha,
Weezard (the damn near indigent):wink:

 

[mrchris]

Hi I'm new and i also an LED grower.
I would ask you if i could post some Pics of my grow?
I'm yousing High power Cree LEDs.

sorry for my bad english