Cannabis Median Heat Units

I’ve seen a few misconceptions from the sceptics regarding my theory. That’s fine, but at least get the full story. You’d have to be obtuse to deny it without testing my theory, but of course given enough people, the internet will always oblige.
Feel free to share and repost it in it’s entirety anywhere if you like. I’ve copied this from @Starsandstripesseed forum. I had posted an explanation on IG quite awhile ago, but IG canned my account and I couldn’t be bothered to appeal or make another one. It’s worth repeating. One day this will be taken for granted.
Cannabis Median Heat Units

I was undecided under which heading to post this as it is something I learned from experiences in each setting; indoor, outdoor, and greenhouse. Why not Beginner? It’s a good fundamental to understand. Clearly the proof is in the pudding, and I’d be happy to see my theory validated, or invalidated, by the collection of high/low temperature data during ripening from all of the testers. The more points of reference, the more accurate the result.

Here’s how I came to recognize the importance of both day and night (median) heat to ripening. As a high latitude grower doing more work indoors than out, I had an idea how long each cultivar took to ripen indoors, where we strived to keep rooms cool, especially at night, for the extra colours. In 2001 I started doing light dep greenhouses in Ticino, CH, with a 11/13 light/dark photoperiod. We noticed that the light dep crops shaved a week off of the ripening of every cultivar. We chalked it up to the extra hour of dark, which likely did have some influence. We didn’t pay as much attention to the median temps as we did to the day time temps, which were usually about 10 degrees Celsius warmer than outside, routinely hitting 36C during summer days. Nights cooled down significantly, to the teens. The constantly vented tunnels were cool at night.

Later in life I found myself growing out sizeable selection crops in equatorial lowlands. These were straight up field runs. Daytime temps were routinely 36-40C, but the nights were still warm, with lows of 24C. This is when I was blown away by the greatly accelerated early ripening, with 60 day indoor cuts finishing in 45 days. Rock fucking solid.

Evaluating the finishing times under various heat regimens is best done with some consistent cuts, but even with seed lines we will see interesting comparisons. Send in your Official Tester reports with high low temp data! If you are really serious about seeing a side by side test of my MHU ripening theory, here’s what you need to do. Set up a few independent chambers and run the trials. Even just two. With everything else being equal (cuts, nutes, medium, lights) run one chamber with highs of 26C and lows of 10C, let the other chamber run at highs of 36C and lows of 25C. If you don’t see/try it for yourself, you’ll never really know. Uninformed negative opinions have zero validity. Please do your own research. I only share it because I have learned by experience. I have nothing to gain from telling you this. Science is whether or not you all can confirm or deny, through replication, the results I have attained observing the correlation of median heat units and ripening times. Prove me right, prove me wrong, but ffs, if you don’t want to run the experiment yourselves, stfu.

I propose that, as with Corn Heat Units, we rank cultivars according to their proven Cannabis Median Heat Units. There are many maps displaying CHU’s to help farmers select the right seed for their microclimates. Corn varieties are well-marked in the CHU’s needed to crop. Vitis vinifera is the same, with grape atlases showing zones in each region by degree ripening days. Syrah needs a lot more heat to ripen than a Pinot Grigio. If you plant the wrong vine in the wrong place it may never ripen to its full potential. Cannabis is a parallel universe. Heat counts, both day and night, affect ripening. That heat affects ripening time is a foregone conclusion to anyone with half a brain, especially bona fide farmers. I only pointed out that we can and should start cataloguing cannabis genetics with this CMHU as part of the technical data of each cultivar. It’s a no-brainer.

If you think that’s stupid, I’ve got news for you… you can find genuine unadulterated stupidity in the nearest mirror.

Thanks for coming to my Ted Talk.

Have a great J, Steve

Don’t expect a lot of replies from me here, I just don’t have the time or patience for sparring with the inevitable morons. I’m just posting it for the benefit of those who care to learn from my experience, and for posterity. In the future this will be a normalized standard specification attached to every cultivar. It’s only a matter of time.

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Howdy @BreederSteve, this would line up with Rèaumur who in the 1700’s theorized that thermal time directly relates to plant physiology, including maturation. Specifically with the noticable maturation of grape varieties at different times with respect to varying locations and temperates.

That said, I think it’s important to view maturity in the context of potential yield with photothermal quotient analysis. Using temperature alone as a driver of maturity may come at the cost of a more idealized yield. I think most ideal would be to find the preferred sweet spot of both yield and maturation, of which would be a personal preference for sure.

Physiological processes are driven by temperature and the fuel for those biological processes come from sugars manufactured during photosynthesis, so in order to speed up maturation it may come at the cost of potential yield as time for photosynthesis is lessened.

Do you think there are different baseline temperatures that can be associated with different cultivars, or rather, do you think the different baseline temperatures help create unique cultivars?

I’d imagine that these variables are part of what goes into the unique terroir of a given harvest and have noticable impact on phenotypical expression. Is this part of the land in landrace and what drives the uniqueness of heirlooms grown outdoors in traditional cannabis producing regions? I think so. Not much unlike how indoor gardens give way to their own unique expressions. It’s all such a fascinating topic of discussion. Awesome of you to bring it to Overgrow.

I think this will be especially helpful for indoor gardeners better trying to ripen and mature long flowering types. For example, those seemingly 22 week types that just won’t seem to finish might just need a bit more warmth and will instead finish more properly in 16-18 weeks as a hypothetical example.

There’s a comment on Icmag where Zamalito recommends some books about cannabis and one of them is a book about plant breeding by Arnel Hallauer titled: Plant Breeding The Arnel R. Hallauer International Symposium. Highly recommend for anyone who finds this topic interesting. Totally agree about the parallels in viticulture and corn breeding as they relate to cannabis. Many blessings and much love

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seems logical that cold temps slow everything down, day or night. thanks for sharing your perspective- i’m afraid the class isn’t as focused on science as they could be. :wink:

dave watson kept his mothers in a dimly lit refrigerator :sweat_smile: to slow them down(maybe a hashchurch episode)

my climate experiences have been Sacramento, CA & Hilo, HI… so I”m allergic to snow :call_me_hand::sweat_smile:

:evergreen_tree: Aloha!

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When it’s cold outside I get a lot less done. When it’s warm I’m moving and getting a lot more done. When I’m surfing if it’s cold I can hardly move, when it’s warm I’m swimming like a fish.

Then to consider, that’s my own unique expression while there are some surfers who have been living in Maine or Oregon and other cold climates like that. Their baseline temperatures for their ability to get work done will be different than mine.

Sort of like different cultivars having different baseline preferences as they relate to temperature and physiological function. Many blessings and much love

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@BreederSteve . This makes perfect sense to my way of thinking. I am a farmer and I have seen this same effect in many different types of plants. A case in point, Pecans trees will grow in my area just fine but the nut shells will not fill with meat because they do not have enough accumulated heat units ( sunshine) over the course of the year. Great topic ! Thank you. :v::grin::+1:

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So anyone that disagrees with you is stupid?

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:evergreen_tree: instead of deleting your post

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I must admit, that part made me laugh out loud. But hey, there is some truth in that statement, lol. Folks should check out this thread for some cool podcasts with @BreederSteve . Seems to me he is a source of knowledge that folks should give a listen to.

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Since you didn’t list any points your skeptics have made that you’re arguing against, this whole thing reads as some self important pick me type of attitude. And it makes me more curious to see what folks have said to counter you. Having grown out your work in the past, I know you probably know what you’re doing, but it sure is inviting the trolls. So are you trying to teach people something or shove shit in the face of someone who said you were wrong?

I do appreciate the step by step, but you need to show that. Right? Maybe your data is somewhere…but it’s not in that post. I’d love to see your data or records you kept during all this. I LOVE science and seeing data. Otherwise you’re free to tell someone they must’ve done something wrong because x or y. I see you telling people to try it or bug off. I know you’ve probably hit your limit dealing with people, but it’s not hard to ignore them. I’d be interested in trying to replicate if it’s there. I guess thanks for taking the time out of your rockstar life to share your rambles with us morons. Cool theory, bud.

Cannabis isnt some magic plant. It reacts the way other plants act. I do think much of this is already studied and it does hold true in some case for some plants. So I do think you’re right. If you’re interested in a discussion, I can link the studies. If not, thanks for the info. Keep rocking.

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Hello. What you’re saying has the point, indeed. On the other hand, the whole text looks like it was made with quite some rage, I guess there’s more emotions than it should be. Look, the experiment should be run and tested multiple time, that’s true. But some basic things that are known to the growers may and probably will be debated prior to that…I mean - we all know what’s gonna be if you burn the plant, right? So what’s the point of calling everyone who calls that idiots just cuz they did not try it?

Thanks for your thoughtful response, @sbeanonnamellow. I was waiting for someone to touch on this. Next to cannabis cultivation, my commercial cultivation experience included 15 years of viticulture. While a hot season may burn off the acid early, and raise the brix, it still takes time to achieve phenolic ripeness. Fast ripening isn’t always an asset in this regard. Wines made from grapes with no acid and high sugar tend to be soupy low end plonk. I haven’t seen or quantified the equivalent issue with aromatics in cannabis, but the ones I had that finished super early definitely were very satisfying in both flavour and effect.

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I’m glad that you can appreciate it! It’s pretty universal amongst plants. Have a great day.

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It’s disingenuous to look for an argument over half a sentence by removing the context from the first half of it. Weak extrapolation. Do better.

IF you think that the correlation between median heat and ripening times, a universal truth throughout the plant kingdom, is stupid…

There’s a lot of things you can disagree with me on and not look stupid, who’s going to win the Super Bowl, does Taylor Swift give good head, whatever. So no, disagreeing with me doesn’t necessarily make you stupid. Disagreeing with the correlation I’ve noted regarding heat and ripening times without actually doing your own comparison definitely does. I saw more than a few fools going down that road. Snark doesn’t trump experience. It just proves them to be pinheaded idiots.

Can you understand the distinction or are you going to double down? I really don’t care, knock yourself out.
Peace, Steve

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I don’t have my temp logs from 2001 and 2017 handy, so sorry. I shared my experience from memory. Even if I posted the numbers, some idiot would say that I made them up, so what’s the point? I invite others to test my theory. I don’t need to show the data, you apparently need me to, rather than seeing for yourself first hand. That’s a you problem, mate. I’ve seen it. That’s good enough for me. I know that my tone can get abrupt, to say the least. Happy to see the study links. Thanks in advance for sharing.
Peace, Steve

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I understand you’ve got a bunch of experience but you have to acknowledge our memories are not perfect. It’s shown time and time again that when we try to remember things, we change the memory. Often. So if you have no interest in ‘finding’ your numbers, I have little interest to be the only one sharing studies or numbers. Some idiot can interpret them however they want, so what’s the point? Advancing the community as a whole means having a trail of breadcrumbs we can double check. We get away from bro science by doing literally anything other than saying “I’ve seen it bro. Go do it yourself.” Bring numbers and bring some facts. I think you’ve done great work. Keep doing it and don’t ride out on your glory from yesteryear. I’d personally like to see the community move away from he said she said and stories.

I’ll still give it a try. But my guess is it’s applicable to some varietals and not others.

I may be getting old, and my memory ain’t what it once was, but I can definitely recall the accelerated ripening of 8 weekers, to 7, and then 6, with the main variable being heat. It’s not complicated. I wish I was good as you at preserving old records, but regardless, the fact remains. Doubters have to see it actually happen for themselves, that’s the point. Not having a hard drive that was seized 25 years ago doesn’t invalidate my findings. Sorry that’s not good enough for you, but again, that’s a you problem.
Have a nice J, Steve

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That whooshing sound was The Point, flying past you unnoticed.

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So, if my wee brain can wrap around this correctly.
Running indoors, day cycle temps, run at 79F.
The dark cycle temps, at 50F. Or what we shoot for now.
Not that I can get down to 50 f at night, I’m more at 68-72 F, just thinking out loud.
BUT if I run at 98 F during lights on, then drop to 77 F, I could see a faster maturing plant?
Well now, I may need to dust off the retired digital ballast, get the 1k bulbs out retirement, to raise my on time temperatures up.
Anyone know, if this through the whole cycle, germination, through the veg cycle, or maybe just as they get to flower?
H’mm got to ponder on this a bit.
Thanks Breeder Steve!!

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Good morning, @webeblzr, I hope that you do test the theory that accumulated heat units affect cannabis ripening times, as they do virtually every other crop. Even if you only test it in flower I’m certain that you’ll see the difference.
Happy Croptober!

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Good morning, @BigF, you heard the whooshing sound, not me. I’m going to try once more before I ignore you. No loss for either of us.
If you want to argue with me about who’s the greatest rock band in history, that’s legit. You love Nickleback, I love Zeppelin. We could argue endlessly, but the fact remains that taste in music is subjective. We could agree to disagree, and even be friends.
On the other hand if you want to argue with me about the timing of sunrise and sunset tomorrow at any given latitude, there’s nothing to dispute. It’s a foregone conclusion, an immutable, objective fact. It’s not simply a matter of disagreeing with me, it’s disagreeing with a universal truth. Now that would be, beyond the shadow of a doubt. stupid.
I know that I used some big words there, but hopefully you get the drift.
My primary residence is in the Okanagan Valley, there’s a lot of fruit, cherries, peaches, apples, grapes. The harvest starts in the south of the valley and moves north. There’s about a 2 week difference in the harvest times of the same cultivars from south to north. The photoperiod isn’t much different, but the south is hotter. Some of the grapes, eg. Syrah, can’t even ripen in the north, but do fine in the south. It has to do with accumulated heat units. Disagreeing with me about subjective things isn’t stupid. Disagreeing with me, and the universe, about objective facts, is.
Regardless, I wish you a Happy Croptober.
Have a good one.

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