Trichomes & Harvesting

So incredibly eye opening. The more and more I read about Marijuana, the more I'm in awe.

Thanks for the good read!

RM3 said:

Except it takes a year (on average) to lose just 7% THC
The science
http://www.unodc.org/unodc/en/data-and-analysis/bulletin/bulletin_1997-01-01_1_page008.html

So, No, it won't work. Best to get a high CBD strain if that is what you want, there are plenty of em out there, I've grown a few

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You are quoting the science wrong.
Dried plant material loses, on average, 16.6% of THC over a year of storage, according to the study you linked.
The 7% you are quoting, which is in fact 7.4%, is the standard deviation, a measure of how much the results deviate from each other. In essence you are misrepresenting the findings of the scientists you are quoting, by a factor over 2.

Another study found that THC, stored in a formulated system @ -18, 0, 4 & 25 degrees centigrade, degraded by ~15.8% to 20% in 10 days, with the numbers rising over the range of 15 months to 20+%, which seems to fit well with the correct percentage of 16.6% in the study you linked (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2921171/).

THCA can be, and is converted to CBNA over time (with CBNA then converting to CBN), and that is why CBN is reflective of the age of a given developing plant, as much as it is reflective of the age of stored plant material.
Of course the amount of CBN in a given plant is also reflective of the particular strain.
But to say that CBN is not present in growing plants, or that it takes a year to see just a 7% degradation into CBN, or that we cannot use the development of trichomes to determine the age and levels of different cannabinoids is just wrong.


Furthermore I'd like to add that scientists on this topic argue that THC + CBN reflects the total THC content of a given plant, regardless of degradation;

M. Stefanidou et. al. said:

In some cannabis products the low proportion of THC is not incompatible with their resinous character, as CBN (a degradation product of THC) in these samples is presented in large proportions. This leads to the suggestion that THC plus CBN content in fact reflects the total THC content, irrespective of degradative changes

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This means that THC content can be understood as THC and CBN, since CBN (the degradative product of THC) can be directly attributed to THC.

Ref; M. Stefanidou, S. Athanaselis, G. Alevisopoulos, J. Papoutsis, A. Koutselinis, D9 - Tetrahydrocannabinol content in cannabis plants of Greek origin, Chem. Pharm. Bull. 48 (5) (2000) 743–745.

k0ijn said:

You are quoting the science wrong.
Dried plant material loses, on average, 16.6% of THC over a year of storage, according to the study you linked.
The 7% you are quoting, which is in fact 7.4%, is the standard deviation, a measure of how much the results deviate from each other. In essence you are misrepresenting the findings of the scientists you are quoting, by a factor over 2.

Another study found that THC, stored in a formulated system @ -18, 0, 4 & 25 degrees centigrade, degraded by ~15.8% to 20% in 10 days, with the numbers rising over the range of 15 months to 20+%, which seems to fit well with the correct percentage of 16.6% in the study you linked (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2921171/).

THCA can be, and is converted to CBNA over time (with CBNA then converting to CBN), and that is why CBN is reflective of the age of a given developing plant, as much as it is reflective of the age of stored plant material.
Of course the amount of CBN in a given plant is also reflective of the particular strain.
But to say that CBN is not present in growing plants, or that it takes a year to see just a 7% degradation into CBN, or that we cannot use the development of trichomes to determine the age and levels of different cannabinoids is just wrong.


Furthermore I'd like to add that scientists on this topic argue that THC + CBN reflects the total THC content of a given plant, regardless of degradation;



This means that THC content can be understood as THC and CBN, since CBN (the degradative product of THC) can be directly attributed to THC.

Ref; M. Stefanidou, S. Athanaselis, G. Alevisopoulos, J. Papoutsis, A. Koutselinis, D9 - Tetrahydrocannabinol content in cannabis plants of Greek origin, Chem. Pharm. Bull. 48 (5) (2000) 743–745.

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What I quoted from the study,,,,,,,

the degradation of THC appears to proceed at a higher rate for the first year than subsequent years and levels off after two years to a rate of loss of approximately 7 per cent per year. Therefore, studies carried out with "old" material could feasibly report a 7 per cent loss per year. It is believed that the percentage loss in THC content is also a function of the initial THC concentration. The higher the concentration of THC, the faster the degradation over the first one or two years.

RM3 said:

What I quoted from the study,,,,,,,

the degradation of THC appears to proceed at a higher rate for the first year than subsequent years and levels off after two years to a rate of loss of approximately 7 per cent per year. Therefore, studies carried out with "old" material could feasibly report a 7 per cent loss per year. It is believed that the percentage loss in THC content is also a function of the initial THC concentration. The higher the concentration of THC, the faster the degradation over the first one or two years.

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You are completely misunderstanding, or more likely, misrepresenting what the scientists found in the study.
What you just quoted again, is what the average loss in the subsequent years AFTER TWO YEARS of storage is; 7% accumulative. That means that after losing 26.8% THC by being stored for two years (see table 2), the plant material following that period (that means year 3 and year 4 consecutively) loses around 7% a year.
The scientists are NOT saying that you "only" lose 7% THC per year. In fact if you look at the science in the study, without misrepresenting what they found, you can see that after 4 years of storage the plant material has lost 41.4% THC, on average, with some samples losing well over 50%. So when you say that you "only" lose 7% per year, you are misrepresenting the data and the findings, by a factor over two! That is wildly dishonest.

If you look at the tables in the study (table 1 through 4), you can see how after 1 year of storage the plant material, on average, has lost 16.6% THC. After 2 years of storage it has lost, on average, 26.8% THC.
It seems like you don't understand what statistics are, and that you don't know how to interpret the numbers.
The scientists aren't saying that it takes 1 year to lose 7% THC, they are saying that AFTER TWO YEARS of storage, the subsequent years the loss levels out somewhat from the 16.6% per year to 7% in year 3 and year 4, on average.


I would warn anyone against taking what you are saying about this topic seriously, when you cannot even interpret a simple statistical analysis correctly.
The scientists, in my opinion, were very clear, and even wrote their findings in very readable language, even to a layman like you;

Study said:

...the degradation of THC appears to proceed at a higher rate for the first year than subsequent years and levels off after two years to a rate of loss of approximately 7 per cent per year.

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I am not sure if I am getting through to you here, but either you are misrepresenting what the scientists found in this study, or you are being facetious. In either case, you are not respecting the science behind the study.

k0ijn said:

You are quoting the science wrong.
Dried plant material loses, on average, 16.6% of THC over a year of storage, according to the study you linked.
The 7% you are quoting, which is in fact 7.4%, is the standard deviation, a measure of how much the results deviate from each other. In essence you are misrepresenting the findings of the scientists you are quoting, by a factor over 2. .

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Yes the square of the variance from the mean or such. But what is your level of confidence in this crap? To be 99.6% confident and have an r-square approaching one is quite impressive. Figures don't lie. Of course liars figure too. So much for my understanding of probability and regressing on a multitude of variables.

haight said:

Yes the square of the variance from the mean or such. But what is your level of confidence in this crap? To be 99.6% confident and have an r-square approaching one is quite impressive. Figures don't lie. Of course liars figure too. So much for my understanding of probability and regressing on a multitude of variables.

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I don't understand what you asking; my level of confidence in what 'crap' exactly?
I feel like you are being sarcastic and making a joke, but I can't be sure, based on the kind of ridiculous logic I've seen on this forum before.

haight said:

Asking? Do you see any question marks? No?
Listen, statistical theory tends to boggle most peoples minds. Thazz all. And like I said, how accurate was that report? How many reviews of said report were critical of methodology, assumptions, and double blind controls.

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Did you read the report? I did and it wasn't all that complex and nothing to do with statistical theory. It was a simple test that tracked change in THC and CBN content over time. They did have controls for the analytical equipment. The error of the measurement was high, but we are talking about extraction of plant material and all the error inherent in the method. Sample sizes were large enough to overcome measurement error.

The figure below was copied from the report. In the first year, %THC weight loss was very fast, roughly 17% and then slowed down thereafter, leveling off to roughly 7%-9% per year after the first year. The change in rate of THC loss indicates there was a different mechanism or process driving early weight loss with a shift to another mechanism, I'm guessing rate limited by diffusion, after the first year.


One problem with using this study to discuss THC loss in our weed it that the THC content of the study weed was pretty low ~2%-4%. Good commercial weed is what, 15%-25% THC? Would THC loss rate be higher at higher concentrations or would it be slower? All I'm saying is that we are extrapolating results from a study using low THC weed to guesstimate what happens with today's commercial weed. Not saying that results from the study aren't useful.

So, leaving the issue of extrapolation error aside, what does it mean really? If I have a sample of weed with 20% THC and 17% degradation during the first year, that weed will contain about 17% THC. After year 2, assuming 8% wt loss, it will have 15% THC and 14% THC after year 3.

Maybe for somebody with high tolerance to THC, the amount lost over 3 years would be significant. To a lightweight like me, probably not.

Fogdog said:

Did you read the report? I did and it wasn't all that complex and nothing to do with statistical theory. It was a simple test that tracked change in THC and CBN content over time. They did have controls for the analytical equipment. The error of the measurement was high, but we are talking about extraction of plant material and all the error inherent in the method. Sample sizes were large enough to overcome measurement error.

The figure below was copied from the report. In the first year, %THC weight loss was very fast, roughly 17% and then slowed down thereafter, leveling off to roughly 7%-9% per year after the first year. The change in rate of THC loss indicates there was a different mechanism or process driving early weight loss with a shift to another mechanism, I'm guessing rate limited by diffusion, after the first year.

One problem with using this study to discuss THC loss in our weed it that the THC content of the study weed was pretty low ~2%-4%. Good commercial weed is what, 15%-25% THC? Would THC loss rate be higher at higher concentrations or would it be slower? All I'm saying is that we are extrapolating results from a study using low THC weed to guesstimate what happens with today's commercial weed. Not saying that results from the study aren't useful.

So, leaving the issue of extrapolation error aside, what does it mean really? If I have a sample of weed with 20% THC and 17% degradation during the first year, that weed will contain about 17% THC. After year 2, assuming 8% wt loss, it will have 15% THC and 14% THC after year 3.

Maybe for somebody with high tolerance to THC, the amount lost over 3 years would be significant. To a lightweight like me, probably not.

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I actually did a test of sorts, took a bud that tested 25% THC and left it sit out on my coffee table for a month, then tested it again it was now 22% in the first test there was zero CBN, in the 2nd test there was 1% CBN which jived with what was said in the report.

RM3 said:

I actually did a test of sorts, took a bud that tested 25% THC and left it sit out on my coffee table for a month, then tested it again it was now 22% in the first test there was zero CBN, in the 2nd test there was 1% CBN which jived with what was said in the report.

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25% THC going down to 22% THC in the first month would be about 12% change in total THC by weight, so yes that jibes pretty well with the UNODC study. Thanks.

Fogdog said:

25% THC going down to 22% THC in the first month would be about 12% change in total THC by weight, so yes that jibes pretty well with the UNODC study. Thanks.

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My God man, 12% vs.17% ? The report results are 42% higher. Jive? You bet.
(Ain't statistics fun?)

haight said:

My God man, 12% vs.17% ? The report results are 42% higher. Jive? You bet.
(Ain't statistics fun?)

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People making hash out of statistics can bring a chuckle. I wonder if that would be bubble hash or kief?

RM3's data was in line with the data in the report. Doesn't prove anything because we can't know what the UNODC test samples would have shown had they been tested in one month.

You confuse statistics with data. Just saying.

Keep your posts relevant to the discussion at hand or the general point of the sticky.
Asking stupid questions and then acting like you didn't ask any questions is not pertinent to the discussion we are having here.

This thread is not a place for you to act out your personal frustrations.

Fogdog said:

People making hash out of statistics can bring a chuckle. I wonder if that would be bubble hash or kief?

RM3's data was in line with the data in the report. Doesn't prove anything because we can't know what the UNODC test samples would have shown had they been tested in one month.

You confuse statistics with data. Just saying.

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It can indeed be fun to see people stumbling trying to understand a simple statistical analysis.

What I find more interesting though, is the fact that a 12% drop in potency, in just 1 month, isn't considered a large drop off in potency by some people in this thread. I'd say that losing 12% of anything, in the span of just 1 month, is a pretty tough loss.

In any case, you summed it up very well, it does not prove anything, since the real data from the study didn't test samples after such a short period.
It would be fun to see what actual scientific results would be in short periods of time, perhaps 1 week, 2 weeks and a month, to get a better understanding of the potency loss.

k0ijn said:

It can indeed be fun to see people stumbling trying to understand a simple statistical analysis.

What I find more interesting though, is the fact that a 12% drop in potency, in just 1 month, isn't considered a large drop off in potency by some people in this thread. I'd say that losing 12% of anything, in the span of just 1 month, is a pretty tough loss.

In any case, you summed it up very well, it does not prove anything, since the real data from the study didn't test samples after such a short period.
It would be fun to see what actual scientific results would be in short periods of time, perhaps 1 week, 2 weeks and a month, to get a better understanding of the potency loss.

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Yes, as a producer, a 12% loss in THC content would, I think, be a big deal. No argument there. The problem would be larger variability so more samples but not that much of a complication.

Fogdog said:

Yes, as a producer, a 12% loss in THC content would, I think, be a big deal. No argument there. The problem would be larger variability so more samples but not that much of a complication.

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Indeed, and I truly hope that we will see a lot more in depth studies on the complexity of cannabinoids and their development in the future, both in vivo and in vitro.

I try to keep up to date on the science, although this specific area is not my speciality. But I do have access to most scientific databases, so do please let me know if there are any specific studies you'd like me to link/upload.
I found a rather interesting, but very specific, study on Albanian Cannabis plants yesterday, which details how cannabinoids mature and convert in that specific region.
It is usually very hard to find broad studies which apply directly to the discussion in this thread, since most studies are very specific. But I do believe we are inching closer to what we are seeking, as Cannabis studies are becoming more and more respected in the scientific community.

i find that most of the studies that people are still quoting were done at least a decade ago, some as much as 50 years ago. the greek study being quoted above is from 99.
i'd really like to see some current studies of new strains that are much more potent than those grown 20+ years ago.
places like NIDA do studies...how can you expect a place named the Nation Institute for Drug Abuse to do a fair, non biased study?
is anyone aware of a non-govermental institute doing fair, even handed research thats not aimed at demonizing marijuana and its users?

Wrong spot I apologize..drying issue(where to?)
Made changes to my setup and forgot about drying woops...now I'm running a one room setup so I obviously only have my venting system in there...I know it's not best but I think my best bet short term is to dry them in there till I can cure...any suggestions,pointers advice..
I run 400's..rooms never about 75...exhaust/Fa and all that good stuff..using stackable mesh drying racks..im contemplating putting them anywhere outside the room but I realize how important my ventilation system is

Dmm said:

Wrong spot I apologize..drying issue(where to?)
Made changes to my setup and forgot about drying woops...now I'm running a one room setup so I obviously only have my venting system in there...I know it's not best but I think my best bet short term is to dry them in there till I can cure...any suggestions,pointers advice..
I run 400's..rooms never about 75...exhaust/Fa and all that good stuff..using stackable mesh drying racks..im contemplating putting them anywhere outside the room but I realize how important my ventilation system is

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im not a hydro guy.
Why carnt you just dry them in another room, garage, somewere else? Just have a fan circulating the air like most of us do.
That way u can get on to your next grow.

Lucky Luke said:

im not a hydro guy.
Why carnt you just dry them in another room, garage, somewere else? Just have a fan circulating the air like most of us do.
That way u can get on to your next grow.

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Smell mainly. I very well may do it that way..haven't decided yet...stinky house or expose buds to light something Ive never done

Dont expose them to light!

If you have to go 4 to 7 days without a grow..do that rather than wreck your work.