The truth about THC percentages?

One of my favorite things to do while blazing is to watch videos and learn about marijuana and cultivation.

Perhaps one of my favorites is pot-tv's Marijuana Man's Grow Show. The most recent Grow Show episode I watched destroyed my understanding of THC content in plants. In the links I attached he makes some great points. And leaves me believing that concepts of what THC percentages are- are completely flawed.

I believe some weed gets you higher than others, and that some weed has more THC than others- but I do not believe their is an objective way to measure such fine qualities of a plant. When they list 18-23% THC what the hell is that 18-23% of?

If anyone understands this concept of THC % than feel free to explain, but for a community so often quoting these percentages I think it is something that should be further examined and critiqued.

Part one: The Grow Show - THC percentages, do they add up?
YouTube - The Grow Show - THC percentages, do they add up? (part 1)
Part Two: The Grow Show - THC percentages, do they add up? (part2)
YouTube - The Grow Show - THC percentages, do they add up? (part2)

And how the hell do you go about calculating how much thc a plant has, is there a DIY way lol? that would be sweet!

I found this....it should take care of marijuana mans questions....and some of my own that were raised after watching that....interesting though isnt it

check it out....and here is the link to the article below Cannabis strength / potency - what does it actually mean?
[FONT=Arial, Helvetica, sans-serif]How is cannabis strength measured?[/FONT]

[FONT=Arial, Helvetica, sans-serif]Definition: Strength is the amount of drug per volume or weight of a sample. By way of illustration alcohol strength is measured in "ABV" - the percent of alcohol per volume, so a 5% beer will contain 5% alcohol, easy. [/FONT]
[FONT=Arial, Helvetica, sans-serif]As the drug the government associates with cannabis intoxication is THC and we're dealing with a solid substance, the strength of cannabis would be expected to be measured in Mg THC per gram of sample, that's where we hit a problem.[/FONT]
[FONT=Arial, Helvetica, sans-serif]Now it's worth mentioning that cannabis is not simply THC, it's a blend of various active substances, the different ratios of which produce a very different effect on the user. However, only THC is usually measured, which produces the first problem when we want to examine changes in the nature of cannabis over time. No measurements of the amounts of the other active chemicals have ever been made by the authorities on anything like a regular basis. This is at least in part explained by the fact that cannabis is illegal and what measurements there have been made have been first and foremost for enforcement, not quality control reasons.[/FONT]
[FONT=Arial, Helvetica, sans-serif]However, at least the strength of cannabis has been measured in terms of THC per gram of sample? Sadly, no it hasn't.[/FONT]
[FONT=Arial, Helvetica, sans-serif]In 2005, UKCIA asked the government's anti drug advertising agency "Talk to Frank" how cannabis strength is measured, we were asked to write to the Home Office:[/FONT]
[FONT=Arial, Helvetica, sans-serif]UKCIA question: [/FONT] [FONT=Arial, Helvetica, sans-serif] Further to a phone chat today (Thursday 19th May) to one of your people[/FONT]
[FONT=Arial, Helvetica, sans-serif] I've been hearing a lot about the strength of cannabis of late. This strength has been quoted as "percent THC", can you explain what this means?[/FONT]
[FONT=Arial, Helvetica, sans-serif] With alcohol, strength is measured in percent alcohol by volume (%ABV), but clearly the THC in cannabis doesn't amount to 10% of the volume nor of the weight, so what is it a percentage of?[/FONT]
[FONT=Arial, Helvetica, sans-serif] As a follow-up question, cannabis isn't simply THC, the other main component is CBD which is known to modify the effects of THC. I have also
seen this ratio reported as a percentage, so how is the ratio of THC to CBD measured?[/FONT]
[FONT=Arial, Helvetica, sans-serif] Many thanks[/FONT]
[FONT=Arial, Helvetica, sans-serif] -----------------------------[/FONT]
[FONT=Arial, Helvetica, sans-serif]
[/FONT]
[FONT=Arial, Helvetica, sans-serif]Home Office reply:[/FONT]
[FONT=Arial, Helvetica, sans-serif] Thank you for your email of 19 May which has been passed to me for reply.[/FONT]
[FONT=Arial, Helvetica, sans-serif] The percent THC is the weight for weight of THC in the dry cannabis sample selected for analysis. A fresh cannabis plant contains a lower proportion
of THC as fresh plant material contains a lot of water.[/FONT]
[FONT=Arial, Helvetica, sans-serif] THC is the main active constituent of cannabis. The.proportion of other constituents of cannabis is therefore not of interest in terms of potency.
The THC acid (delta-9-tetrahydrocannabinolic acid) is converted to THC when cannabis is heated (e.g. in a cigarette) so some scientists use gas chromatography (GC) analysis to measure THC. This method. effectively measures the total available THC, as the sample is heated in the injection port of the GC.[/FONT]
[FONT=Arial, Helvetica, sans-serif] Ratios of cannabinoids are sometimes measured when comparing cannabis samples. The ratios are relative responses.obtained by the particular method of analysis and so do not directly relate to actual ratios of the percentage compositions. Absolute proportions of CBD would not normally be measured.[/FONT]
[FONT=Arial, Helvetica, sans-serif] Richard Mullins
Drug Legislation and Enforcement Unit
Home Office[/FONT]
[FONT=Arial, Helvetica, sans-serif]So what does the above tell us?[/FONT]
[FONT=Arial, Helvetica, sans-serif]"The percent THC is the weight for weight of THC in the dry cannabis sample selected for analysis. A fresh cannabis plant contains a lower proportion of THC as fresh plant material contains a lot of water."[/FONT]
[FONT=Arial, Helvetica, sans-serif]It's unclear what they mean by "dry". Plant material, of the sort you might buy from your dealer - even if dry in the normal sense - is still composed largely of water, so what do they mean by "dry"? It would seem that what they're talking about is a desiccated sample, that is a sample in which all the water has been removed, in effect destroying the biomass material, leaving the oils produced by the plant. We did ask for confirmation on this point, but received no answer.[/FONT]
[FONT=Arial, Helvetica, sans-serif]It's also worth pointing out here that the measurement is actually referred to as "potency", not strength. This careful use of words is typical of the Home Office when it's being economical with the truth. The reason this is important is because the amount of oils the plant produces is not a constant fraction of the overall weight. It will depend on which part of the plant is sampled and how it's grown.[/FONT]
[FONT=Arial, Helvetica, sans-serif]So the measurement they make is a percentage by weight of the oils in the sample, not of the overall weight of the sample.[/FONT]
[FONT=Arial, Helvetica, sans-serif]Is potency directly comparable to strength? It's not clear that it is. In which case, the strength of cannabis over the years has never really been measured. It's also apparent from the reply that no standard system for making the measurement has been employed ("some scientists use gas chromatography")[/FONT]
[FONT=Arial, Helvetica, sans-serif]Based on this type of measuring regime, it's clear that making meaningful conclusions about changes in strength is going to be difficult.[/FONT]
[FONT=Arial, Helvetica, sans-serif]How are samples selected for measurement?[/FONT]

[FONT=Arial, Helvetica, sans-serif]Here we hit perhaps the biggest problem as no statistically valid monitoring of the cannabis on sale has ever happened. What measurements have been taken have been made on samples seized by the police in raids. How representative these samples are of the general situation is unknown, but as a sampling method it wouldn't be considered reliable enough for serious scientific analysis.[/FONT]
[FONT=Arial, Helvetica, sans-serif]So: to recap:[/FONT]
[FONT=Arial, Helvetica, sans-serif]The property measured - "potency" - bears an uncertain relation to "strength"
There has been no standard methodology for making the measurements over the years.
The samples measured are unlikely to be a statistically valid sample.[/FONT]
[FONT=Arial, Helvetica, sans-serif]So what conclusions can be drawn from all this?[/FONT]
[FONT=Arial, Helvetica, sans-serif]The most authoritative study in recent times was conducted by the European Monitoring Centre for Drugs and Drug Addiction in 2004 - read it here.[/FONT]
[FONT=Arial, Helvetica, sans-serif]The report makes it clear that the data is somewhat unreliable and it's therefore difficult to draw firm conclusions, but it accepts there has always been strong cannabis which can compare to today's offerings. It makes the point that home grown is going to be fresher and thus stronger (cannabis "goes off" with time as the THC breaks down).[/FONT]
[FONT=Arial, Helvetica, sans-serif]There is undoubtedly some strong cannabis available these days, but there always has been. It's reasonable to suppose that, because it's fresher there will be a higher proportion of stronger samples (= better quality), but overall there is no evidence to support the claims of a massive increase in strength.[/FONT]
[FONT=Arial, Helvetica, sans-serif]It should also be mentioned that commercial supplies of cannabis - herbal and hash - are often highly contaminated these days, a direct result of police action aimed at disrupting the supply. It's therefore obvious that most consumers aren't getting the higher value strong product.[/FONT]

wow! GREAT INFO! I was really pissed because no one was commenting on this thread- and it is a incredibly valid and important discussion to have in our community. Your post had a lot of info in it- put still leaves the debate somewhat up in the air- at the end of the day, in my opinion- its pretty fair to say that percentages really aren't shit. They are somewhat reflective of 'potency' but ultimatley its pretty clear when nearly every seed bank has their better strains at a very wide percentage spread- usually 18-25% for the good stuff... this is a 7% spread of a number we dont understand how it has been measured... lol-

So to throw around percentages is to simply spread false information. Get the word out- best way to know if its good is to smoke it- so pass me some of your shit so i can judge it... for science man!

Lacy tells a true story...

Its an excellent post. Worthy of rep +++++++++

thank you kindly sir.

Haha, Thats laughable Mr. Cron. Its one of the few posts that isn't a story

but thanks all the same

OB Cron Kenobi said:

Lacy tells a true story...

Click to expand...

I am glad it finally got some eyes, especially yours Lacy- I was following your journal for the longest time- but you had so many friends stopping by posting I would get lost and have to read a ton! but you are an excellent grower and certainly are well known here at RIU so thanks for shedding some light to my struggling THC controversy lol

Awww how swweet. Yes I know what you mean about my journal. I often get lost in there too.

I think many members here would agree with your thread here. Just give it a bit more time to catch on.

It most certainly is worthy of a read especially to those considering a potent new strain (which is most of us I would guess)

I better move on before I completely hijack your thread.

I've been known to do that

Later Mr. Cron.

OB Cron Kenobi said:

I am glad it finally got some eyes, especially yours Lacy- I was following your journal for the longest time- but you had so many friends stopping by posting I would get lost and have to read a ton! but you are an excellent grower and certainly are well known here at RIU so thanks for shedding some light to my struggling THC controversy lol

Click to expand...

OB Cron Kenobi said:

wow! GREAT INFO! I was really pissed because no one was commenting on this thread- and it is a incredibly valid and important discussion to have in our community. Your post had a lot of info in it- put still leaves the debate somewhat up in the air- at the end of the day, in my opinion- its pretty fair to say that percentages really aren't shit. They are somewhat reflective of 'potency' but ultimatley its pretty clear when nearly every seed bank has their better strains at a very wide percentage spread- usually 18-25% for the good stuff... this is a 7% spread of a number we dont understand how it has been measured... lol-

So to throw around percentages is to simply spread false information. Get the word out- best way to know if its good is to smoke it- so pass me some of your shit so i can judge it... for science man!

Click to expand...

Why thank you sir....I saw you said in another post you had some unanswered posts....so I stopped on by. This really interests me as well...not that the whole pot thing doesn't but....I agree. the percentages are kinda overrated....go with what you personally like...and the best part of that is trying them all!!!...lol. either way it's nice to see a legitimate thread...and not some bs question...I have em sometimes but I definitely thing the more knowledge the better the buds. rep on the post....I am gonna do a little more investigating on this...I still didnt quite get all the info I wanted. I'll be back.

that is some crazy shit/ thanx for the info

wait a minute :


But if ya add 27% with another 27% = 54% !

clearly you have more thc...


am i wrong ?????

cuz basicly.. he is saying 27%-100% = 73 + 73 = 146 - 200 = 54% THC.. clearly u have extracted more ThC than other matter ???

so yeah it would be stronger... or not ?

anyway... huh huh huh PAss Pass

My tolerance level is pretty low so I don't care how much THC the bud has. (then again ive never had shwag)

good read however. i enjoy learning new things.

Straight from the horses mouth. Have to agree with you aswell reading about cultivation when your ripped is primo. Cheers for this dude a good read.

DWR said:

wait a minute :


But if ya add 27% with another 27% = 54% !

clearly you have more thc...


am i wrong ?????

Click to expand...

Yes, you are wrong.

Think about it this way. If everytime you breed two plants together their THC % was added in the resulting child plant then every plant would have 100%. Hell in a plant starting with just 1% THC you would have 100% THC in just 6 generations:

1% + 1% = 2
2% + 2% = 4
4% + 4% = 8
8% + 8% = 16
16% + 16% = 32
32% + 32% = 64
64% + 64% = > 100%

Kludge said:

Yes, you are wrong.

Think about it this way. If everytime you breed two plants together their THC % was added in the resulting child plant then every plant would have 100%. Hell in a plant starting with just 1% THC you would have 100% THC in just 6 generations:

1% + 1% = 2
2% + 2% = 4
4% + 4% = 8
8% + 8% = 16
16% + 16% = 32
32% + 32% = 64
64% + 64% = > 100%

Click to expand...

is that a fact that if u combine two plants that the thc muliplys itself ? ....

---

your maths are the same thing i basicly said or not ?

DWR said:

is that a fact that if u combine two plants that the thc muliplys itself ? ....

---

your maths are the same thing i basicly said or not ?

Click to expand...

No, I'm saying that's wrong. That's NOT how it works and my example was to show why it can't possibly work that way.

There is no mathematical formula per se. You just use what animal and plant breeders have been doing for centuries; selective breeding.

Basically you would increase the frequency of a desirable trait by only allowing the organisms that posses that trait to breed.

In this case the desirable trait is high THC content. So, for instance, you take two plants that produce better than average THC and breed them together. Some of the offspring will produce less THC than the parents but some will produce more. You continue to do this breeding until you have stabilized the high THC trait.

honkeytown said:

[FONT=Arial, Helvetica, sans-serif]The ratios are relative responses.obtained by the particular method of analysis and so do not directly relate to actual ratios of the percentage compositions. [/FONT][FONT=Arial, Helvetica, sans-serif][/FONT]

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SO...in other words.....this number is, at best, an approximation of my ass.

This is frustrating.....with all the enthusiasm surrounding cannabis....it seems that someone somewhere should be responsible and take one for the team. Grow things under constant variables, same nutes and environ, water cure to prevent any water weight.....

.....break it down to the genetics....then sample scientifically instead of arbitrarily....

and report factual numbers on percent THC....or even better, have a number for thc, and total cannabinoids, and instead of the weight of the oils or a "relative ratio"....it should be an empirical number with meaning

DWR said:

is that a fact that if u combine two plants that the thc muliplys itself ? ....

---

your maths are the same thing i basicly said or not ?

Click to expand...

your forgetting that only the quantity is being doubled. not the percentage..

1% + 1% = more of the 1% because there is still 99% remaining that has to get added..

Weed has not got more stronger, its just that there is more stronger weed. The genetics wont mutate like that much in so little time, its just using plants with alledgedly 'superior' genetics to fertilize each other, maybe sourced from opposite sides of the world, ya know what i mean, i think every company has scouts that go round lookin for new flavours n highs from local and wild grown weed over the globe. Those traits the companies/customers desire, are merged, and the offspring of those plants are crossed with yet more plants, and those superior genetics dominate the marketplace. Same with the animal industry. So its not that weed has got stronger, humans been cultivating this stuff with INTENT for thousandds of years, but now, those stronger sub-species of cannabis (i know there technically isnt a subspieces classification of cannabis in terms of all the different phenotypes there are around the world) have been transploted via human intervention to all corners of the world now. There are still plenty of farily original strains. So if you want something different, maybe try growin some of the old school strains again :/ im doin some durban poison in a couple months, thats meant to be really strong sativa, but apparantly has just 8% or so THC. I really wanna try some yum-bolt, haiwayan etc too. Interesting thread man, you just answered my question!