Investing in new lights LED or HID?

[secondtry]

Hey all,


Here are a few more papers about UV-b I will download today and post in full, they look very good. One concern about UV-b is the genetic instability it can cause in some species of higher plants. To avoid any such damage I apply UV-b for 2-4 hours a day at midday when the plant would naturally be irradiated with higher UV-b. On the topic of what wavelengths comprise UV-b I am pretty sure it's 280-315 nm because the first paper cites UV-b as 280-315 nm (and discuses the other definitions of UV-b range), the second paper cites UV-b as 280-320 nm and the fourth paper cites UV-b as 280-315 nm.

The topic of wavelength is kind of important considering one study found CBD converts to THC from (at least) 235-285 nm.

Note on chemotypes:

This a function of genotype which means growing environment has little effect upon the ratios of cannabinoids to each other. However, the quantity of each cannabinoid is commonly thought to be a function of phenotype which very basically means 50% of the quantity of THC (for example) is determined by genetics and the other 50% of the quantity of THC is determined by the environment. This is why breeding via comparative "chemotype I" cultivars is wise. From a very young age one can find the chemotype and for example if cultivar 1 has a higher ratio of THC/CBD than cultivar 2 one would cull cultivar 2, well, that is if one seeks to increase the chance of breeding for the highest THC producing plants. (that is an unbiased method that is great way to cull from hundreds of seedlings)

(Here are the three most common chemotypes found, taken from Hillig, et al, 2003)

• Chemotype I = higher THC to CBD ratio (>>1.0)
• Chemotype II = almost even THC to CBD (~1.0)
• Chemotype III = lower THC to CBD (<<1.0)

References:

1. David W. Pate

Possible Role of Ultraviolet Radiation in Evolution of Cannabis Chemotypes
Economic Botnay, 37(4), 1983, pp. 396-405
http://www.jstor.org/pss/4254533​

2. M. G. Holmes

Non-Damaging and Positive Effects of UV Radiation on Higher Plants
Environmental UV Radiation: Impact on Ecosystems and Human Health and Predictive Models. Volume 57. pp 159-177. 2006.
http://www.springerlink.com/content/n110t68p89671563/​

3. Dieter Treutter

Significance of flavonoids in plant resistance: a review
Environmental Chemistry Letters. Volume 4, Number 3 / August, 2006. pp 147-157.
http://www.springerlink.com/content/q14t4206065701v1/​

4. CHARLES F. MUSIL, SAMSON. B. M. CHIMPHANGO and FELIX D. DAKORA

Effects of Elevated Ultraviolet-B Radiation on Native and Cultivated Plants of Southern Africa
Annals of Botany 90: 127-137, 2002
http://aob.oxfordjournals.org/cgi/content/full/90/1/127​

 

[secondtry]

Major typo:

I am a poor speller and for some reason I tend to spell "irradiance" as "irridiance" [sic]. I was going to fix all the instances where I misspelled irradiance in this thread but I am not that ambitious; thus this post for all the previous typos. I entered irridiance into my spell-checker whitelist and forgot about it...oops.

 

[supermanlives]

hid kicks led ass.

 

[Japanfreakier]

The net is filled with LED grows which are a little less than truthful (hey, what's that hid light just out of frame?) so I don't trust them.

 

[Zombo]

hid kicks led ass.

The net is filled with LED grows which are a little less than truthful (hey, what's that hid light just out of frame?) so I don't trust them.

Fine. Don't read or post in LED threads then. You made your stance clear. Have a nice day!

 

[NiteTiger]

Second, ...Edit: You know what, not even worth it. Lab experiments != real world. Talk about something you have actually done.

Zombo, this isn't an LED thread, it's an HID v LED thread, so I'm confused by what you are trying to say?

 

[secondtry]

@ All,

Here is the main paper about UV-b and THC, as promised in full text attached to this post.

I am glad I re-read this paper, it is a real gem, I forgot it presents info we can use and verifies other claims I have made such as light saturation point of > 1,500 PPFD. In this post I will write about the UV-b/THC paper only, in the next post of mine I will write about other UV-b issues and in the posts following that I will write about PPFDi (ie., "incident PPFD"); basically counting the PPFD over the whole canopy, not just the top of the canopy. I also will write a bit about photosynthesis and it's usage, etc., I spent about two hours at the library today with a huge book entitled "The Handbook of Photosynthesis; Volume 2" and I scanned many papers into PDF, this is very good info I have yet to find elsewhere (I want the book but it's a few hundred dollars)...

Below I will list a few topics I want to point out regarding this paper, one is a big error I made and how I fixed it. And below the quoted section of the paper I will post figures with captions showing the various effects of UV-b and PPFD upon Co2 assimilation by leaf:​

1. I made an error in converting the UV-b irradiance used in the following study. The researchers used UV-b "dose" to mean the total amount of UV-b irradiance over the whole day (i.e, kJ/m^2/3-hr), while I used their data as UV-b at a single instance (i.e., kJ/m^2/sec). I have been using about 200-400 uW/cm^3 for a single measurement, but I should be using 300-400 uW/cm^2 as total amount of irradiance over a day. This means the irradiance of UV-b will be much lower at any given point, it's the sum UV-b irradiance we should be measuring to replicate the study below, and in turn we are replicating the average highest UV-b irradiance of a day under clear sky and minimum solar zenith in Colombia, South America (0' lat, 3 km elevation, June, 1980). The study below found 13.4 kJ/m^2 of UV-b to be an effective daily irradiance which is about the same daily irradiance of UV-b found naturally in Columbia as reported above.

Here is my math, if someone can error check me that would be great:

Previously I thought the researchers applied 13.6 kJ/m^2 of UV-b, but as I noted above it turns out they applied 13.4 kJ/m^2/3-hr. Needless to say that's a huge difference! It seems I have been providing too much UV-b this whole time, I guess because I UV-b lamp on a light mover it didn't effect things negatively as it could have. After reading this paper I found my error and below I present math I used to find the correct UV-b irradiance per second for 3 hours to replicate the study:

​

(the following data assumes the absolute uW from both the a SolarTech 6.2 UV-b meter and the spectroradiometer used in the study are the same and it's probable they are not, thus this data is a close approximate)​

Here is the correct math:

1. (13.4 kJ/m^2/3hr) / 3 = 4.47 kJ/m^2/hr

2. (4.47 kJ/m^2/hr) x 1,000 = 4,467 joule/m^2

3. (4,467 joule/m^2/hr) / 3,600 = 1.24 joule/m^2/sec

3. 1.24 joule/m^2/sec = 1.24 watt/m^2

4. (1.24 watt/m^2) x 1,000,000 = 1,240,000 uW/m^2

5. (1,240,000 uW/m^2) / 10,000 = 124 uW/cm^2
​

Thus:

(124 uW/cm^2) x 3 hours = 372 uW/cm^2/3hr as the total daily irradiance of UV-b​

Or:

(248 uW/cm^2) x 1.5 hours = 372 uW/cm^2/1.5hr as the total daily irradiance of UV-b

​

Or:

(62 uW/cm^2) x 6 hours = 372 uW/cm^2/6hr as the total daily irradiance of UV-b
​

Thus if we are copying the work of Lydon, et al,. (1986) we would use a 3 hour time frame of UV-b irradiance at ~124 uW/cm^2 as measured from a UV-b meter like the SolarTech 6.2. For a 1.5 hour time frame of UV-b irradiance we want 248 uW/cm^2. For a 6 hour time frame of UV-b irradiance we want 62 uW/cm^2. I will probably use 100-150 uW/cm^2 as a goal (possibly avg. over whole footprint) for 4 hours a day, or considering hot spots I may use 60-200 uW/cm^2 as a range for the footprint of irradiance for 4 hours a day. Basically I am trying to reach 300-400 uW/cm^2 of total UV-b in less than four hours each day.​

2. This study cited > 1,500 PPFD as the light saturation point for cannabis, about same irradiance from the other three studies I posted about cannabis.



3. This study used UV-b irradiance pre or post solar noon



4. This study used VPD of ~1.45 kPa when studying cannabis




John Lydon, Alan H. Teramura, C. Benjamin Coffman

UV-B RADIATION EFFECTS ON PHOTOSYNTHESIS, GROWTH and CANNABINOID PRODUCTION OF TWO Cannabis sativa CHEMOTYPES
Photochemistry and Photobiology. Volume 46, Issue 2. Page Numbers 201-206​

Introduction:

...

Pate (1983) reported that C. sariva populations originating from high UV-B environments contained little or no cannabidiol (CBD) but high levels of A'-tetrahydrocannabinol (Ay-THC), while the opposite was true for populations from low UV-B environments, and proposed that the two distinct C. sativa chemotypes (drug and fiber) evolved as a result of selective pressures brought about by UV-B radiation. Fairbairn and Liebmann (1974) reported that the Delta9-THC content of leaf tissue from UV irradiated greenhouse-grown drug-type C. sativa was 23% greater than non-irradiated greenhouse-grown plants. However, neither the spectral distribution nor the daily dose of U V radiation were reported. The objectives of this study were t o test: (a) The physiological and morphological insensitivity of both the drug- and fiber-types of C. sativa to UV-B radiation; and (b) to correlate this insensitivity with a change in production of A'-THC or CBD in drug- and fiber-type plants, respectively.


Results:

Light saturation of COz assimilation ( A ) in the drug- and fiber-type controls occurred at PPFDs greater than 850 umol/m^2/s (Fig. 1). There was no significant difference in A from 26 to 32°C in either clone, although A tended to decrease at temperatures > 3 0 T (Fig. 2). The light and temperature response of A and A,,, were unaffected by UV-B radiation in both drug- and fiber-type plants (Figs. 1 and 2). Data on the physiological and morphological parameters of the drug- and fiber-type controls are presented in Table 1. None of these physiological parameters were significantly affected by UV-B radiation in either chemotype (data not shown). The cannabinoid levels and profiles of the drug and fiber-type controls (Table 1) were similar to those reported for other Jamaican and Czechoslovakian populations of C. sativa (Holly et al., 1975). The major cannabinoid (CBD) in the fiber-type plants and the minor cannabinoids in drug- and fiber-type plants were not significantly affected by UV-B radiation (data not shown). Only the THC content in leaf and floral tissues of drug-type plants increased significantly with UV-B radiation. Regression analyses indicated that there was a significant linear increase in THC with UV-B dose in these tissues (Fig. 3). The concentration of THC in leaf tissue increased by 22% and 48% with a total daily UV-B dose of 6.7 and 13.4 effective kJ/m^2, respectively, as compared to controls. The same levels of UV-B radiation resulted in a 15% and 32% increase in Delta9-THC, respectively, in floral tissues. The R2 values, based on regression (see Fig. 3 for equations) about all sample observations were 0.32 and 0.31 for floral and leaf tissues, respectively. However, R2 values based on regression about the sample means were 0.99 for both tissues. Thus the regression equations provide a suitable model for UV-B induced THC production in these tissues.


Discussions:

...

In conclusion, the Delta9-THC content in leaf and floral tissues of greenhouse grown drug-type C. sativa increased linearly with UV-B dose.

THC increase from daily dose of UV-b​

PPFD effect on Co2 uptake under UV-b
​

Temp effect on Co2 uptake under UV-b​

 

[secondtry]

edited double post

 

[secondtry]

..Edit: You know what, not even worth it. Lab experiments != real world. Talk about something you have actually done.

I don't know what your deal is, but I gave you everything you asked for and you still are upset? It seems you don't like the answer more than anything else...

I wrote these things to start:

1) I used Uv-b as with the lamp Ultra Vitalux at 20-22", how more 'hands-on' can one get?

2) I have references to studies backing up what I write
​

You asked for links, so I gave them to you. You then misread a single abstract and decided I was wrong. I explain how you misunderstood the abstract and that I will upload the full paper for you, and how what I wrote is not wrong. You don't wait for the full text of paper but instead accuse me of only reading and no real-wold usage, even tho I originally wrote I have used the very same setup I am writing about...

Have a nice day, I really don't understand why your upset, why isn't this perfectly valid? In fact, why is it not more valid than a few pot head sitting around doing a 'smoke test'???

 

[secondtry]

Two quick thoughts:

1. According to my calculations the total amount of UV-b irradiance we want to achieve if we are trying to mimic the work of Lydon, et al,. (1986) is about 370 uW/cm^2/daylength (i.e., 13.4 kJ/m^2/daylength). The key here is it's not the incident irradiance, but the total UV-b irradiance over the daylength. Our goal would be to reach 370 uW/cm^2/daylength, thus we could use an irradiance just over 0.1 uW/cm^2/sec for one hour to reach 370 uW/cm^2/daylength. Just a thought...


2. My calculation seems kind of low in terms of level of irradiance, it seems low but maybe not. I need re-check my math in the morning, if anyone seems errors please let me know.

 

[NiteTiger]

I don't know what your deal is, but I gave you everything you asked for and you still are upset? It seems you don't like the answer more than anything else...

I wrote these things to start:

1) I used Uv-b as with the lamp Ultra Vitalux at 20-22", how more 'hands-on' can one get?

2) I have references to studies backing up what I write
​

You asked for links, so I gave them to you. You then misread a single abstract and decided I was wrong. I explain how you misunderstood the abstract and that I will upload the full paper for you, and how what I wrote is not wrong. You don't wait for the full text of paper but instead accuse me of only reading and no real-wold usage, even tho I originally wrote I have used the very same setup I am writing about...

Have a nice day, I really don't understand why your upset, why isn't this perfectly valid? In fact, why is it not more valid than a few pot head sitting around doing a 'smoke test'???

Who said anything about a smoke test? I'm simply saying that you have no real experience with what you're claiming, yet you present it as if it is set in stone fact. You grow with UV, and you say it gives an "...increase (total) THC content in cannabis flowers by around 20-30%"

Fine, grow same strain, same method, one with UV, one without, and have them tested. Actually prove the theory in your garden. Have you seen an increase in total THC content in your garden? Had it tested?

For growers, the proof is in the garden.

Anything less is just interesting reading.

You have no real world example to back up your claims. Even in your own garden.

 

[secondtry]

I am so sick the attitude most cannabis growers have in that it has to be the person posting who is the one who generated the data. Why is the info I provided not valid? Tell me?!? It's more valid than any growers thread I have ever seen.

It seems you have a stance/belief and you want to be correct, so you keep changing the standard you are holding me to; that's fine, but if you keep it up I will just ignore you.

And yes, for the untold times: I use UV-b when I grow and yes it seems like it increases the THC verses plants without it, but it's ALL subjective conjecture, THAT is why the refer to the study and other like it (there are at least three other studies showing UV-b can increase THC) why you refuse to see it is beyond me but it's a common attitude at cannabis forums, and it's a lame one...

Like I wrote, I have all 'parts' needed to carry out comparative analytical assays of raw cannabis, oils, hash, etc., using TLC with JustTLC scanning program. Then I can say yes or no if THC was increased X amount over the mean baseline. Once I have THC standards I can say how much THC is present but not until then, and by then I hope to have a GS.

P.S. I never claimed UV-b gave my plants a specific increase of THC, I simply wrote UV-b has been found to increase THC by X amount and that is why I use UV-b. Either learn how to quote me correctly and stop putting wording/ideas in my mouth, or don't quote me at all!

HTH

 

[mad librettist]

And brake lights, etc, not for cannabis unless it's in a power limited environment. One town tried them for stop light someplace last winter and they didn't get warm enough to melt ice and snow...grab the steering wheel and go for it! ha.

that town was on NPR, I remember that story. They have no plan to switch back to lights that need constant changing and suck too much power, despite their snow melting abilities. Now let's look at HID in public spaces. Can you think of any light less enjoyable to observe things in that an HPS street lamp? Nasty. Here's a New Yorker article about it.

I'm trying to figure out my next step, HID vs. LED. But I see a lot of excessive hating on both sides. Makes it tough to decide.

But then I look at what verdant green did with 63 watts, and it gets me wondering.

our planet is a power limited environment, and I'd like my grow to be more responsible.

 

[NiteTiger]

I am so sick the attitude most cannabis growers have in that it has to be the person posting who is the one who generated the data. Why is the info I provided not valid? Tell me?!? It's more valid than any growers thread I have ever seen.

Because it has not yielded results in a real world scenario. As it is, it is nothing more than an idea for a grower, not a proven technique. Real results matter more than paper results.

You're even doing exactly what I suggested,

Like I wrote, I have all 'parts' needed to carry out comparative analytical assays of raw cannabis, oils, hash, etc., using TLC with JustTLC scanning program. Then I can say yes or no if THC was increased X amount over the mean baseline.

And then you go on to say exactly what I'm trying to get across! Let me bold the relevant part

Once I have THC standards I can say how much THC is present but not until then, and by then I hope to have a GS.

Exactly my point! You can't say how much of an increase, but it seems like you did:

Adding 375 uW/cm^2 of UV-b has been found to increase (total) THC content in cannabis flowers by around 20-30% and in leaf by around 40-60%.

Which is an exact quote, exactly as I've quoted it every other time. I'm not misquoting you. That is exactly what you wrote. And that reads to me as you saying there will be a 20-30% increase in THC if you use UV. Maybe that's not what you meant, or not how you meant for it to come across, but that is how it reads to me, and others that have messaged me as well.

It seems you have a stance/belief and you want to be correct, so you keep changing the standard you are holding me to; that's fine, but if you keep it up I will just ignore you.

The only stance that I have is that the presentation of your information, which I even commented that I found interesting, may be misleading. I'm not arguing whether you're right or you're wrong, but I'm saying, just as you have, that it can't be said for certain until in situ tests are conducted.

I even agree with you. I would be arguing the exact same point to someone who said there was an increase in THC, for whatever reason, without having actually done a side by side test with clear results, ie. a lab test.

It almost sounds like we're saying the same thing, just from different directions. I don't think it can be said that adding UV to a garden will increase THC without running a single strain under the same conditions, with the exception of UV. That's my stance. That's it. No equivocations.

I'm not saying that it doesn't, or it won't. I know growers, that I respect as near masters of the cannabis cultivation art, that do use UV. I've debated adding UV to my garden, and will probably do so in the next grow I run.

But I, nor the growers I referenced, would say there is an increase in THC without doing exactly as I described.

And perhaps that's not what you were saying, either. But what I quoted, right from the start of our little side discussion here, sure makes it sound that way.

That's my only issue, is in the presentation of the information. Not the information itself, which, as I said earlier, I found interesting. So, perhaps it is a matter of perception, or a misunderstanding, but if so, it is one that many others shared.

To clarify, you were not claiming that adding UV to your grow would increase THC by 20-30%, correct? But the information you've provided has convinced you that a proper test is in order?

Am I understanding you now?

 

[secondtry]

Hey Mad.

I'm trying to figure out my next step, HID vs. LED. But I see a lot of excessive hating on both sides. Makes it tough to decide.

Tough to decide? I laid out all the "why's" already, there should be nothing to think about. The facts are there thus: LEDs don't offer a good spectral quality (SPD), nor irradiance (PPFD). It's that simple!

I don't hate LEDs, I do very much dislike the lies LEDs sellers tell and how they don't understand their product at all in terms of what is ideal for growing cannabis...

But then I look at what verdant green did with 63 watts, and it gets me wondering.

I never wrote LEDs can't grow good cannabis, I wrote they do not compare at all with correctly used HID's, and that's 100% accurate. HID used correctly will outproduce and out grow LEDs, period. I have provided many studies showing this.

our planet is a power limited environment, and I'd like my grow to be more responsible.

So use a digital ballast, or use LEDs and grow sub-par cannabis (when compared to that grown under HID correctly).


The whole LED vs. HID argument bothers me because it's not a real choice, and even tho I have laid out all the facts about light quantum physics people still think LEDs are good...arrrgh! I think that is because people don't grasp what I am writing about because they are not used to the concepts or terms.

Trust me Mad.L, do not get LEDs. HID used as I have written are the way to go. And the SPD from the Horiliux blue is money.

 

[secondtry]

OK NiteTiger,

It's obvious you want to be correct and you are willing to ignore all the science I presented, thus I am ignoring you from now on, but for a last gesture I will once again try to explain this to you. I am tired of this back-and-fourth, it's dumb, so here is my last post to you:

2nd try wrote:

I am so sick the attitude most cannabis growers have in that it has to be the person posting who is the one who generated the data. Why is the info I provided not valid? Tell me?!? It's more valid than any growers thread I have ever seen.

Because it has not yielded results in a real world scenario. As it is, it is nothing more than an idea for a grower, not a proven technique. Real results matter more than paper results.

WHAT???

UV-b IS shown to increase THC in a REAL-WORLD scenario (i.e., greenhouse). Just because there are no pics doesn't meant it's not true. WTF man, what are "paper results"? I hope you don't think pics are proof. Give me a break on that stupid "pics or it didn't happen" bullshit! There is no way you can be serous, or maybe you just want to be correct, truth me dammed huh?

I use UV-b too, in the real-world.

NT wrote:

2ndtry wrote:

NT wrote:

2ndtry wrote:

Like I wrote, I have all 'parts' needed to carry out comparative analytical assays of raw cannabis, oils, hash, etc., using TLC with JustTLC scanning program. Then I can say yes or no if THC was increased X amount over the mean baseline.

And then you go on to say exactly what I'm trying to get across! Let me bold the relevant part

Once I have THC standards I can say how much THC is present but not until then, and by then I hope to have a GS.

Exactly my point! You can't say how much of an increase, but it seems like you did:

I never wrote how much of a THC increase my cannabis had! I wrote how much Lydon, et al., found and if you even bothered to read the paper you are arguing about you will see that Lydon, et al., reference another study which also found large increase in THC from UV-b irradiance.

I don't see why this SO hard for you understand, my 13yr old niece could grasp these matters...

NT wrote:

2ndtry wrote:

NT wrote:

And then you go on to say exactly what I'm trying to get across! Let me bold the relevant part

Once I have THC standards I can say how much THC is present but not until then, and by then I hope to have a GS.

Exactly my point! You can't say how much of an increase, but it seems like you did:

You can't be this dense! I never wrote how much my cannabis holds in terms of THC. TLC as I will use it WITHOUT a standard will be comparative, so yes, I CAN say how much the THC increased over baseline but I can't say how much total THC is present (by weight or %), only how much THC is present relevant to the baseline.

NT wrote:

2ndtry wrote:

Adding 375 uW/cm^2 of UV-b has been found to increase (total) THC content in cannabis flowers by around 20-30% and in leaf by around 40-60%.

Which is an exact quote, exactly as I've quoted it every other time. I'm not misquoting you. That is exactly what you wrote. And that reads to me as you saying there will be a 20-30% increase in THC if you use UV. Maybe that's not what you meant, or not how you meant for it to come across, but that is how it reads to me, and others that have messaged me as well.

If that is how you interpret that sentence then that's your problem (and the people who PMed you), not mine. Maybe you need an English refresher course? That sentence is 100% accurate and correct, and nowhere did I claim that of my cannabis, only of the work by Lydon, et al. You are upset at something that doesn't even exist!

2nd try wrote:

NT wrote:

It seems you have a stance/belief and you want to be correct, so you keep changing the standard you are holding me to; that's fine, but if you keep it up I will just ignore you.

The only stance that I have is that the presentation of your information, which I even commented that I found interesting, may be misleading. I'm not arguing whether you're right or you're wrong, but I'm saying, just as you have, that it can't be said for certain until in situ tests are conducted.

GRRR!

In vivo tests have already been done!!! (Maybe you should brush up on your Latin too, hummm?) The work from Lydon, et at., (1986) and of work of Fairbarin, et al., (1974) were NOT in vitro! Fairbarin, et al., found a 23% increase in THC from UV-b irradiation in a greenhouse.

NT wrote:

I even agree with you. I would be arguing the exact same point to someone who said there was an increase in THC, for whatever reason, without having actually done a side by side test with clear results, ie. a lab test.

This is why I am so frustrated with you: All of that HAS ALREADY BEEN DONE! Did you not read the work of Lydon, et al., or of David Pate???

I will be able to analytically assay cannabis as I wrote. Lab assays with GS are not very accurate dependent upon the quality of standard used, and the standards available from US companies (like CP) are not >99% pure according to a few sources I have.

NT wrote:

It almost sounds like we're saying the same thing, just from different directions. I don't think it can be said that adding UV to a garden will increase THC without running a single strain under the same conditions, with the exception of UV. That's my stance. That's it. No equivocations.

We are saying the same thing, but you keep ignoring the FACT that what you ask for I already provided in the work of Lydon, et al, etc, etc.

When I used UV-b or growing (I'm not growing right now) the non-irradiated cannabis seemed less intoxicating; but that's only subjective.

NT wrote:

I'm not saying that it doesn't, or it won't. I know growers, that I respect as near masters of the cannabis cultivation art, that do use UV. I've debated adding UV to my garden, and will probably do so in the next grow I run.

But I, nor the growers I referenced, would say there is an increase in THC without doing exactly as I described.

So what? Just because they are as clueless as you doens't make what I wrote and the work of countless researchers null-in-void. Just because you are behind the curve doesn't mean the curve doesn't exist.

NT wrote:

And perhaps that's not what you were saying, either. But what I quoted, right from the start of our little side discussion here, sure makes it sound that way.

That IS what I am saying, and I am saying it has been found in real-world experimentation with real cannabis. What you want has already been done decades ago!

NT worte:

That's my only issue, is in the presentation of the information. Not the information itself, which, as I said earlier, I found interesting. So, perhaps it is a matter of perception, or a misunderstanding, but if so, it is one that many others shared.

Well I can't help you or other understand any better than I already have. I am very frustrated with you and I think this post shows it (I hope so anyway). You seems to want to ignore the science I present and tell me I am misrepresenting the truth; that is something I work very hard NOT to do.

NT wrote:

To clarify, you were not claiming that adding UV to your grow would increase THC by 20-30%, correct? But the information you've provided has convinced you that a proper test is in order?

I am stating (once again) that both the work of Lydon, et al., (1986) and of Fairbairn, et al., (1974) showed a increase of THC from UV-b of around 30-50% for leaf and 15-30% for flower (Lydon, et al.,) and a THC increase of 23% from UV-b (Fairbairn, et al.,). I am also stating that other evidence and research points to the theory (proven by studies above) that UV-b can increase THC and that THC is photoreactive. I am also stating that by adding UV-b irradiance a grower like yourself should be able to increase THC in flower and leaf.

NT wrote:

Am I understanding you now?

Somehow I doubt it...

 

[mad librettist]

makes sense 2nd, but why not just present LED as appropriate for power restricted scenarios (self-imposed or otherwise)? I know you said that, but that's not the general feeling. There's a bit of a tendency to give them negative emotional weight in you posts. Sure, it may not be as good as HPS, but in my book, THAT is not as good as the sun. All three of those are better than what I have now, CFL's!

there's always something that is in some way better, because every choice is about weighing relative advantages and disadvantages, no? So helping me make my long term plans is about making sure I understand all the strengths and weaknesses, so that I can compare those to my actual situation and place.

In situ, btw was a good word for NT to choose. It implies so much in the scientific sense, but especially something about place in the art of living sense.

wiki, of course:

In biology, in situ means to examine the phenomenon exactly in place where it occurs (i.e. without moving it to some special medium). This usually means something intermediate between in vivo and in vitro. For example, examining a cell within a whole organ intact and under perfusion may be in situ investigation. This would not be in vivo as the donor is sacrificed before experimentation, but it would not be the same as working with the cell alone (a common scenario in in vitro experiments).
In vitro was among the first attempts to qualitatively and quantitatively analyze natural occurrences in the lab. Eventually, the limitation of in vitro experimentation was that they were not conducted in natural environments. To compensate for this problem, in vivo experimentation allowed testing to occur in the originate organism or environment. To bridge the dichotomy of benefits associated with both methodologies, in situ experimentation allowed the controlled aspects of in vitro to become coalesced with the natural environmental compositions of in vivo experimentation.
In conservation of genetic resources, "in situ conservation" (also "on-site conservation") is the process of protecting an endangered plant or animal species in its natural habitat, as opposed to ex situ conservation (also "off-site conservation").

 

[secondtry]

A real test of LED vs HID:

​

I once again offer to test lamps with Li-Cor PPFD meter for REAL data. Thus we can compare LED vs HID on terms of PPFD which as I have shown should be 1,300-1,500 for cannabis. While PPFD doesn't take into account spectral efficiency of the lamp (the quality of the lamp, ie., SPD) PPFD is still a very good quantitation and comparison method mostly because the Quantum Efficiency of blue vs. green vs. red photons is not such a huge difference in the PAS (Photosynthesis Action Spectra), thus PPFD (irradiance) is the more important factor.

I already wrote how I will carry out these tests. I will follow exactly the method used by Sanjay Yoshi, Ph.D. I will make 3-D images of the irradiance at a few distances from canopy.

Once I test lamps I will make a website and present all the info. At that point the LED vs HID argument goes to hard data which LED manufactures/sellers/users/etc can't refute or adjust to fit their goals.

If LEDs are really SO good why hasn't any LED seller yet contacted me? Or any LED user but one nice person here on ICmag? LEDGirl claims to be purchasing an expensive piece of equipment to measure her LEDs but when I asked her what she is buying she would not answer me...

I find it highly objectionable that LED sellers are selling LEDs with all kinds of claims without testing a single panel for PPFD! (converting from lux to PPFD is not analytically accurate or valid, and yet that is what LEDGirl and other LED sellers pawn off as PPFD data, what a joke!).

It further confuses me why people by into the claims of LEDs sellers hook-line-and-sinker without a singe piece of testing data from LED sellers (and no lux doesn't cut it). The same can be said for HID sellers too, SunMaster wouldn't tell me PPFD values (dumbasses), but we know at least HID emits high PPFD.

I plan to test many HID and LED lamps, reflectors and ballasts (and combos) with the PPFD meter (like Dr. Yohsi has done for reefing). I will present all the data I gather so we can make sound judgments on lamps.

The method used by Knna at gardensecure is not valid as his spreadsheet has far too great of an error margin and is based upon lux data converted to PPF (often mis-termed as PAR watts or PAR irradiance) which is then converted to Quantum Yield Density (QYD) and/or Yield Photon Flux (YPF).


Let gets real testing underway! Anyone interested?

 

[Dope Boy Magik]

3 GEN 90W UFO!!!!! http://www.htgsupply.com/viewproduct.asp?productID=52466

 

[mad librettist]

So, if LEDs are really SO good why hasn't any LED seller yet contacted me? Or any LED user but one nice person here on ICmag? LEDGirl claims to be purchasing an expensive piece of equipment to measure her LEDs but when I asked her what she is buying she would not answer me...

bro she's trying to make a living. would YOU write you back? I would certainly not. She could be using the time chasing a sale or troubleshooting for customers instead of arguing with some guy who will never buy her product, and is convincing others not to buy her product. There's a bit of a sense that these early sales are funding the process of tweaking the technology, but many MJ growers are willing to take the risk. What's more, you can still grow a crop with 63w LED array from LEDgirl that will pay for itself in 3 months if the product is sold in the northeast US.

re: photos, I don't think photos could make your point. just analysis.

One thing though, isn't a greenhouse different in many ways from a typical indoor grow? Humidity, (filtered) real sunlight, etc...?