LED Lab 2009

[knna]

Research/ just growing

Research/ just growing

I think we should differenciate too between the people who want to research and the people who just want to use LEDs instead of other lighting ways.

We cant obligue to the second group, that is the majority, to calculate how much uE they are using and all the data. They may aport valuable info anyway, at least of what works better for each one.

For research, we need accurate measurements.

I do both ways. I have a main cab that must produce the pot I use. Although I try to have well determined the amount of light in it, my priority with it is production. I try different thing in it, but I cant become crazy on what I do, I cant f**k the harvest.

On the other hand, I have two other small growing chamber where I can prove anything, and where I try to have all very well carcterized.

 

[knna]

There will continue to be theories until someone actually knows how to conduct an experiment. Meaning control ALL the other variables and isolate the spectrum. The intensity needs to be the same, air temps, co2 levels, nutrients, ph, training method, humidity, amount of roots per clone....In order to prove ANYTHING, I would first need to see a few harvests in the different chambers (its SO much easier to control things by doing it at the same time) with the same EXACT conditions. If these two chambers can't yield like with 95% (I'd want even more to 'prove' something when comparing tiny effects) within each other with the same conditions, how could you prove anything at all?. I doubt anyone has even accomplished that, so just don't be saying crap like I got 7% more grams/watt ONLY because of the LEDs...I'll be starting/building my next box soon which will pretty much ensure the same 'constants' within each chamber and allow for the testing of a certain variable. The thread will be in the design section prof course..Its going to be 4 - 1sq ft chambers, gotta keep the math easy of course... I know it will help later when I'm testing the results and tring to get some numbers together

We dont need to PROVE anything. We are not trying to write an scientific study. There is no need for strict controlled grows. At the end, we are going to use experimental results for many growers, with different growing experience and skills, using different strains...

But we need some standarizing on the way we share our results, so they are relatively comparable and, on a first stage, allows us to find what works better, not at the subjetive eye of a individual grower, but over objetive measurements, and on a second stage, going delimiting the percentages of each wavelenght that produces the mix more effective (g/uE).

Maths and accurate measurements will allows us to accomplish it, but more due to the accumulation of results and its stadistical meaning.

Two growers using same plant and same lighting setup surely are going to have different results depending of their growing skills, growing style, etc.

A plant grows limited for the resource that gets exhausted earlier. On indoor, its usually light when all the rest is Ok, but its not always so. A nutrient deff may limit production and plant growth before light.

There are too many different parameters that affect plant's growth, so its impossible to pretend to isolate all and vary only the lighting. We just try to do it the best we can.

Its going to lead to higher variability on the results than those of a scientifically controlled study, but on the other hand, we have the advantage that we are a lot of growers. As more growers sharing their results on a research project, the most meangliful and significant the results obtained using stadistical tools.

Our strenght is the number, and the only need to take advantage of it is standarizing units and measurement between us.

 

[DaVinci]

knna and shogun, think I can comfortably agree with everything you have both said. Nice link, by the way, shogun. I really like how well laid out that booklet is. One of the main issues that keeps people from being able to post in uE or PAR watts is that they either don't know convert them, or the bulbs they are using are not rated for anything but lumens. I am one of many that have been guilty of this for both of these reasons.

Well, if it's broke, ya gotta fix it. I'm having difficulty figuring out how to determine PAR watts and UE for given wavelengths of LED, which is frustrating, because I find a lot of sites that give general conversion factors for HID bulbs, but not for specific wavelengths like LEDs use.

Knna, I was wondering if you could briefly school me in where I might find information on how to convert lumens to PAR watts or uE for individual wavebands? I can't for the life of me seem to find a site that tells me explicitly, and this is fucking up some of my graphs. I'd like to be able to contribute more, but as is, I'm not knowledgeable enough to calculate the uE for my theoretical setups.

 

[DonkeyPunch]

Of course, grams is another unit that need to be clarified. I believe that we need to weight both the total harvest (whole plant matter, except for the roots: stems, leaves and buds) and the buds alone. Preferably on fresh weight, although ideally fresh and dry weight should be reported. We need that in order to let out the equation the way each grower process yield. Aditionally, it allows us to study how the light affect the weight distribution between the different parts of the plant.

I kinda get where you are going here, but fresh weight being mostly water may be skewed by the fact that some people may water thier plants more than others in a medium like soil. I could see some potential for wild variations in weight depending on the grower.

It seems to me a dry weight would be more accurate, though I suppose some people dry thier plant material more than others as well which would also skew results.

Then of course I am sure some strains hold more water than others all on thier own, even if given the same amount of water as other strains.

Anyway - Just my two cents, which don't mean much... I am glad to see this going on. I look forward to the day LED is figured out, and likely by that time, LED will be cheap enough for the average person to use.

 

[Jay_Druthers]

lumens=radiant flux*683*luminous efficacy

radiant flux = lumens/(683*luminous efficacy)

now how accurate this is depends on it being a single frequency( leds do have a span so may be some tolerance to it)
other wise you have to deal with integral stuff. But for leds other than white it
should work out ok.

heh maybe I should delete this. the integral is important for converting back and forth.

you would have to do this with the spd chart to get real numbers.

sorry if this was misleading

it would work if radiant power was in a single wavelength and lumens where radiant power in a single wavelength. (ie monocromatic: single wavelength or a very small range of wavelengths, not sure how small range it would be 5nm or 40nm?).

swagging: if any thing you could add 14% to the lumen when radiant power is calculated and subtract 14% from the lumen result when the lumen is calculated. even closer.

lumens-14% of lumens=radiant flux*683*luminous efficacy

radiant flux = lumens+14% of lumens/(683*luminous efficacy)


luminous efficacy chart

http://hyperphysics.phy-astr.gsu.edu/Hbase/vision/efficacy.html

Eye vs Plant-Growth Curves


http://www.thekrib.com/Plants/Tech/lighting.html#10




example
640 40lm 1watt rated, .735 watts at 350ma = swagged 310mw radiant flux, 100 array at $2.50 =$250 = 31 watts of radiant power and 73.5 watts of led power to dissipate.
660 17.3lm swagged 5watt rated, 3.5 watts at 1000ma = 500mw radiant flux, 100 array at $10.00 =$1000 =50 watts of radiant power and 350 watts of led power to dissipate.



also how much more efficient is 660 vs 640 to the plant.

 

[DaVinci]

sweet action. exactly what I was looking for! the rest of that site also helps explain everything well.

did you round those example numbers off, druthers? I tried replicating the equation with your examples, and I'm getting slightly different results....rounding would explain it. Just want to make sure I'm doing it right.

 

[Jay_Druthers]

Yeah I'm a major swagger, I rounded them, it wont give you par or the other photon based numbers, but uncorrected for the eye radiated power gives a good start for comparisons.

My idea for a led light is cheap cost, low heat, so no or little fan, low power consumption, and a 1.5-2 foot plant with say 4-6 inter nodes and some decent bud structure.

 

[knna]

I kinda get where you are going here, but fresh weight being mostly water may be skewed by the fact that some people may water thier plants more than others in a medium like soil. I could see some potential for wild variations in weight depending on the grower.

It seems to me a dry weight would be more accurate, though I suppose some people dry thier plant material more than others as well which would also skew results.

Then of course I am sure some strains hold more water than others all on thier own, even if given the same amount of water as other strains.

Anyway - Just my two cents, which don't mean much... I am glad to see this going on. I look forward to the day LED is figured out, and likely by that time, LED will be cheap enough for the average person to use.

Yep, if fresh or dry weight represent better yield is an old debate. As there is valid arguments on both sides, there is no "best" way, so thats why I suggest to use both for research files.

The only study about was performed in the cannastats project, and it clearly result in fresh weight being less affected, in a stadistical way, that dry weight for how each grower precess yield and the water content at the moment of harvest.

Its more due that, due the manicured dry weight is on average just 15% of the total fresh weight, little variations on the dry weight are way larger in percentage.

While the different water content at the moment of harvest may induce an error margin of +-10% of the fresh weight, differences on dryness and manicuring process may induce error margins of +-150%.

So having the info about fresh weight is a must in order to avoid that large error. But having both fresh and dry weight would be the best. One important thing when studying the effect of light is determine the distribution of weight between different parts of the plants.

For example, one thing that does SOG a very productive method, apart of the reduced veg time, is the higher ratio bud/total plant than with other styles of growing. But light intensity and photoperiod clearly plays a role on this distribution. There is evidence on that extended photoperiods may results on higher ratio bud/plant than shortened ones.

So any serious study trying to find anything about MJ growing should use both fresh and dry weight, because both add info, and having both together allows to extract many more conclusions than using just one and strongly reduces the error margin (always present, on the other hand).

Unfortunatelly, Ive noticed, after many years on MJ forums, that grower's ego strongly affect dry yield reports. Fresh weight is less prone to manipulation, intentional or not.

 

[knna]

About the debate on radiometric output vs photometric output (conersion between lm to PAR W or uE), please check my spreadsheet, that carefully does it, apart of many things more.

It has all coversion factors, as the values of the photopic curve for each nanometer (lm to PAR watts), energy of the photons of each wavelenght (PAR W to uE). With them, the spreadsheet calculates the average conversion factors (lux to PAR W and/or uE) for a given spectrum. It does it with more accuracy than any other tool you may find on the net.

This is a pic of the looking of the upper part of the sheet, that reports the final results of a given spectrum. Its of the Hortilux:

On the upper right corner, there is the spectral results alone. On the top center, applied to the power of the lamp (using same brand ballast).

LER (Luminous Efficacy of Radiation) of 370 (lm/W) is the amount of lm that produces 1 PAR Watt of thast spectrum. With this figure, once know the spectrum, is easy to know the energy efficiency of any light source if you know how many lm it emits (which sometimes is difficult with LEDs, but not for other lights).

PPF/Klm figure informs about how many uE are 1000lm (or, more interesting, how many uE/m2 are 1000lux; so with a simple light meter you may know light density at any given point, preferably at top of canopy). You just need to multiplicate lux reading by that figure to get uE/m2. Without the need of a quantum meter or a spectrorradiometer. Just some time to introduce the spectrum (if its not already there) and measure with a light meter.

PUR and PYF figures are "virtual" ones, adimensional, obtained weighting PPF (uE) by McCree or Inada photosynthetic response curves and cannabis absorbance.

PYF/PPF and PUR/PAR W resumes the average efficacy of the spectrum according to those curves and cannabis absorbance (the sheet is specially designed for MJ. In order to use with other plant, you will need to introduce its light absorbance).

Then there is info about the spectrum distribution, both in PAR W and uE. R, G, B percentages, R/B and R/Fr ratios. And phytochrome stationary equilibrium (φ Pfr/Ptot) for the whole spectrum.

On the bottom, there are all the conversion factors needed to perform all the calcs.

 

[asde]

looks like the hortilux is crap if your data is correct, nice work

can you upload your results for other bulbs too?

 

[knna]

looks like the hortilux is crap if your data is correct, nice work

can you upload your results for other bulbs too?

Well, that is a tool to help analyzing a bulb. Carefull comparision would be needed to say what is crap...

Comparing with other regular HPS lamps, Hortilux gets somewhat lower ratings, but not for too much. When comparing it with other blue enhanced HPS lamps, it gets one of the better ratings.

I dont think this is the thread to compare different bulbs, but I think this case may be usefull to our topic of discussion. How to determine what bulb /light work the best for growing cannabis?

My tool gives a lot of info about the energy efficiency and the spectrum of any bulb. But what do we should use to judge that info? Nobody knows yet the optimal spectrums for growing MJ.

Blue enhanced HPS sacrifize some energy efficiency in order to get a little more blue. At the same time, amount of uE for each PAR W drops a little aswell. Both factors reduce the efficiency of blue enhanced HPSs (uE emitted for each watt burned).

But it, at least supposedly, is a trade off: energy and photon efficiency for increased efficacy of the spectrum.

As there is no any serious study along all the MJ forum about it, its impossible to be sure. No measurements, only subjetive opinions for growers. Some swear by the Hortilux, some says its crap. The only way to know it would be measuring the spectral efficiency of Hortilux vs standard HPS to see if the reduced efficiency is compensated by the increased efficay of spectrum.

HPSs emits a low amount of blue. 5-10% of the total emission (on PAR W). But its taking into account only the pure blue, while they emit the most energy on the short wavelenghts into the cyan range (500-520nm), that technically isnt considered blue, but that in many aspects works on the same trend (throught the job of carotenoids).

The hortilux, with about 13.5% of the energy on the blue, seems to cover pretty well this range, while others HPS, at least if we dont take into account cyan emission, seems to emit too little of it.

I think that increased blue emission worth on the cases when using high irradiance levels, where it induces stomata opening, increasing intercelular CO2 content, allowing plants to photosynthetize more light that on other case would be wasted. While when using medium-low irradiances, it dont have any benefit, but the reduced photon output penalize productivity. I believe this show us that maybe there is not an optimal spectrum, but some of them, depending of the irradiance used. But this is just a personal opinion, not checked at all. I dont use any HID lamp for growing.

smokinshogun, I get the values from the graphs published from manufacturers. Not ideal, but its the best avalaible. But Ive been able to check final result with some lamps with those figures published and error margin (always present) stand controlled, almost always below 5%.

For the lamps I have, I measure its spectrum using a spectroscope. With LEDs, specially narrow bandwith ones, is a must to measure them if you want to have any decent accuracy. Acurrately measurement of peak emission shift with increased current and temperature is the only practical way to caracterize some LED's caracteristics.

Visit this thread (and those linked from there) for more info: http://www.gardenscure.com/420/lighting/117933-bulb-analyzer-tool-actualized.html#post1132481

 

[mrchris]

Wow this tool is fu**** Awesome!!
Thank you for sharing this.

Oh and i think this could be interesting for you.
http://www.candlepowerforums.com/vb/showthread.php?t=220118

 

[LeoRexTyrannus]

I agree with KNNA radiometric based numbers are the only one that seem to correspond with the actual effects on the plant.

Just as a common sense exercise compare LED and HPS on PAR efficiency based on SPD, HPS is instantly demolished, however HPS is still out yielding in the real world, what does it have the HPS lacks... it certainly isn't the right spectra so we go to what he was talking about about photons and uE, the LED is indeed inferior in photon emission.

Take for example Knna's spreadsheet, now in his example he showed it calculated out that a 1000 watt equals roughly 370 PAR Watts. So the next step would be to take 370 Watts of LED and compare directly in a chamber test. But I will take the foot in the mouth in this instance and say that even if the PAR Watts are equal as long as the HID has the superior emission of photons you will see superior results in the HID biomass wise.

Knna you were just saying a few posts back your new array is around this wattage I believe?

Ok going back to what I said since we know 370 watts of PAR in LED is going to be very expensive to build relatively then we should do this same type of experiment with a far lower amount of watts, perhaps a 250W HPS vs the equivalent PAR watts in LED if just to prove it's the photons that are more important than spectra.

I was reading in an old biology text book from the 80s that photosystem a or photosystem b can be powered by a photon of any color, though not efficiently as with the proper spectra.

This could explain why in heads up vs. type tests the far more PUR and PAR efficient LED setups lose to the far less PUR and PAR efficient but far more uE potent HID. Basically the raw photon count is making up for inefficiencies in spectra.

If the above trend proves to be true then to test it we simple need to find a way to match photon emission regardless of costs in one controlled test to either support this line of investigation or to negate it.

I studied PUR and PAR when I first read about LED and all things being equal it's the uE of photons that seems to be the issue at this point.

 

[billyjojimbob11]

So after some more , I think what really matters is....
The total yield, using a certain size space, over a certain amount of time (not just days, also photoperiod totals) , with a certain amount of power. You must then 'reduce' (using the formula) all these variables to pinpoint the effects on the actual spectrum. This is how we can begin to compare people's results...

I'm glad you figured out what really matters...
LOL!, maybe Ill just post my pics and let the people compare the results of
Grams per watt

WHERES YOUR PICS? WHERE IS YOUR GROW, HOW MANY TIMES DO WE HAVE TO COMPARE THEORIES OF POSTERS WITHOUT SEEING THEIR BUDS? WHO ARE THESE PEOPLE? THIS IS NOT AN ORGANIZED EXPERIMENT, IF YOU WANT THAT, KNNA AND GANG ARE ALREADY DOING IT @ CANNIBUS CULTURE.

FOR THOSE WHO WANT PLAIN RESULTS WHICH I HAVE PROMISED.
I WILL POST THE AMBER SUPPLIMENTED PROCYON AFTER THE CURRENT EXPERIMENT WHICH ENDS THIS MONTH.

EQUIPMENT:

1 x procyon homegrownlights.com
1 x 12 watt warm white p4 cree ledsplus.com

SOIL:

1/2 Fox farm Ocean Forest
1/2 Perlite
24 oz cup Venti Starbucks

NUTES:

pergallon

1 tbs alaska fish emulsion
2 droppers Schultz plant food
1 tbs Fox Farm Big Bloom

TEMP:

73-83 deg f

HUMIDITY:

50%

VEG TIME:

0 Veg, flower after root

Next experiment will call for Amber spot light with Edison Opto Emitters.

Any questions, ask smokinshogun

 

[billyjojimbob11]

Sorry, Im saying, apply your math to your theory to your grows...Pls dont tell me what I shall and shall not post.

Appreciate that people give a shit enought to post somthing for you digest and analyze. Go back 2 years in all of the misc forums and you can find that we have already covered every scientific and mathmatic theory imaginable, and everything your posting now has already been covered, sorry...
And anyway, most people here experimenting are having fun, thats what its about, this is not about doing things "the right way" according to smokinshogun...

Also, it's not about convincing HID giys to come join the led revolution...lol

BTW, i hear that your current setup is 400w hps?

Describe your led setup please.

 

[DaVinci]

It's cool man.

Everybody chill. We already had this discussion. No need to fight. As smokingshogun said earlier, he's just got a really, really direct way of speaking. I don't think there are any hard feelings intended. I'm willing to let it slide. My 2 cents.

@billyjoe, how far into your amber experiment are ya? probably too early to see any visual indication of improvement, but I'm an impatient nag.

@knna.....you WOULD have your own spectroscope. You bastard. I want one sooooooo bad. I don't suppose you know of any cheap ones good enough for these purposes? I don't really feel like shelling out $1500 to know what kind of light I'm putting out....

 

[LeoRexTyrannus]

@Smoke, empirical is impossible under these conditions, not a single one of us has funds to construct a facility to create the needed environmental controls.

I can see the frustration of the members of this thread with hands on experience, we could argue about testing methods until we all die of old age and nothing would be accomplished. I truly do thank every since LED grow on the internet, there's something to be learned from them all. I thank every single every adopter and tinkerer for laying the groundwork for the rest of us. Organics and empirical are simply not friends, given this fact let us instead use the method of consensus as it's the method that has made the most progress in these past few years and will continue to enlighten the community at large as more and more hands on tests are conducted and concluded.

Ways in which a grower could make this grow more empirical in nature would include chamber growing, using identical equipment in each chamber except for lighting of course, using clones from the same mother, using the same nutrients including mixing them in one large batch so as to eliminate water as a variable, feeding the before mentioned water in measured dosages, sharing a common air intake split to the individual chambers thus eliminating air as a variable to the fullest extent reasonably possible, doing the same for the exhaust vents/ports.

The point being nothing man made is perfect as man is not perfect, and to seek to attain perfection is therefore insanity.

With this in mind, if we can achieve something akin to the above, or at the very least agree on a standard drying period and method to draw consensus on final weight of buds between a singular growers crops then I believe we're heading in the most positive direction that is feasibly reasonable.

And with that I say amen to this whole argument, calm down fellas he may be zealous but a bet a few hands on grows will break that spirit.

@Billy I totally agree if they won't accept CMH, and they won't accept LED, and they won't possibly accept Sulfur Plasma.... well their loss right? They'll adopt them when they're left in the proverbial dust.

 

[knna]

@knna.....you WOULD have your own spectroscope. You bastard. I want one sooooooo bad. I don't suppose you know of any cheap ones good enough for these purposes? I don't really feel like shelling out $1500 to know what kind of light I'm putting out....

Hey, DaVinci, my spectroscope is a very cheap one. I cant buy a 4000€ spectrorradiometer, at least if I want to stand married

So I supply the limited cash with imagination. I did my "poor man spectrometer". A cheap spectroscope (astronomical) attached to a digital camera. It gets the descomposed spectrum of light.

I use that spectroscope because some friends give it to me, but indeed the only you need is a difraction grating over the camera. A 625 lines difraction net gives a resolution higher than 0.5nm. Other cheap spectroscope may be build with a card box and a CD.

Obtaining the SPD from a pic of a descomposed spectrum requires some work. You need to process the image (format, basically, from color image to 16bits B&W) to be able to process it with Virtual Chart, that is another free program for astronomy that obtain a SPD from a descomposed spectrum in grey scale.

The format and processing of the grey scale is easy and fast, what is more demanding is to calibrate the camera-spectroscope (or camera-difraction net) setup, using a pic of a well known spectrum (both fluorescents and HPSs have caracteristic peaks of narrow bandwiths). But once that its done, all the rest is almost automatic.

This allows to identify peaks with very high accuracy. And to know accuratelly the SPD of narrow bandwith LEDs. With wide spectrum sources, the sensibility of the camera must be take into account, and that is not always easy to find. Its possible to calibrate the setup, but then a spectrum with an exact SPD is required (not only the main peaks).

Wow this tool is fu**** Awesome!!
Thank you for sharing this.

Oh and i think this could be interesting for you.
http://www.candlepowerforums.com/vb/...d.php?t=220118
Yesterday 02:18 PM

Thank you, mrchris. I know that thread pretty well. Ive digged many times in it. Unfortunatelly, it rarely states the LED being tested, but the lighting device. But he has posted some useful spectrums there.

Ive been registered at CPF since many time ago, but lately I post little there. Since they opened the Marketplace and Newbie gone, CPF is not the same. But I learned most I know about LEDs on that forum

 

[LeoRexTyrannus]

If I suggest photons as the measurement of choice it's simply because based on the rules of PAR and PUR current LED should be yielding or out yielding HID. Given the fact we know it isn't I am forced to assume it's exactly because as Knna said it simply lacks an equal or greater amount of photons.

Look at Weezard's example, he's using CO2 to augment his plants metabolism, in effect he is accelerating their metabolic cycle to compensate for a lack of photons which are provided in an outdoor environment in spades.

His method obviously works from the photographic evidence, but it's a work around and not a solution to the photon issue.

May I add that this may be evidence of why the TI SmartLamps and SmartBars can't match an equivalent HID in biomass.

 

[Weezard]

Close. No cigar.

Close. No cigar.

That is incorrect, LTR.

If you have more than enough light, sufficient nutes and good transpiration, your plant will be able to process extra CO2
If you don't have enough light, CO2 won't help at all!

A grow is only as good as it's weakest link.

A cutting under my 150W. led array grew slightly larger than one grown under tropical sunlight, because it was able to use the extra CO2 provided.

I'm going back to lurk and learn mode now.

Wee Zard