Cannabis - a desert plant.

Discussion in 'Growing Organic Marijuana' started by Sc00byD00bie, Sep 2, 2019.

  1. So, reading Frenchy Canollis' Dimensions of Ripeness (linked below) he mentions cannabis being a desert plant and refers to an article "Cannabis The often misunderstood desert plant" which talks about how cannabis originally evolved as a desert plant, or a "Xeric" ((of an environment or habitat) containing little moisture; very dry.) plant. As such cannabis developed survival mechanisms to deal with low moister environment, one of which is the trichome, which helps trap humid air in a boundry around the plant surface.

    According to both Canolli and the article, dry environment with low humidity will promote more trichome development, and high humidity will not (or do the opposite?). There is also mention of the fact that with high humidity the plant will uptake less water through the root system which in turn means it can uptake less nutrients from the soil.

    This makes me wonder about how this correlates with the common notion that cannabis should be grown in humid environment (following VPD charts for instance). The article even goes as far as recommending avoiding foliar applications as much as possible (I am assuming this is during flower).

    We've all heard the stories about this one grow where the plant was subjected to extremely stressful factors during the bloom period but the grower was surprised to find the plants turned out to be the most potent they have every grown.

    Anyway, I thought it would be interesting to open this up for discussion, if you have thoughts or experiences regarding this subject please feel free to share!

    Dimensions of Ripeness (part I)
    Dimensions of Ripeness (Part II)
    Dimensions of Ripeness (Part III)
    Cannabis The often misunderstood desert plant
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  2. interesting!
    like most others I've heard that stressing the plants to some degree was suppose to increase trichome production as the plants defense mechanism.

    makes me wonder if maybe the VPD chart ,would be better for limiting to the veg stage and when in flowering THAN go with the lower RH for the "stress"?

    and while he considers cannabis a desert plants, I can see this for some cultivars, but others came from originate from very non-desert like climates so how does he explain the differences from that?
    I haven't read the articles yet so maybe he answers that....

    will be very interested in seeing what you MUCH more experienced growers think based on your all experiences.
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  3. Hey Sc00b,
    I have read these articles before, and have also read a little into dry-farmed cannabis. I agree that some varieties are desert plants, but I wouldn't agree that all of them are. The trichome is a feature on many plants, not all of them desert plants.
    As a gardener, I have always noticed better health of my plants, and less pests, when the soil isn't constantly kept moist - that there are some wet/dry cycles within reason. This is probably because of the environment I grow in. I think a lot of the notill community that is based in the NW are biased towards moist soil because of their environment, and their success further cements that opinion. In my environment, that would invite all manner of pests and disease. I truly think if we grow outdoors, we have to adjust to what suits our environment.
    As for the ripeness levels of resin glands, I always wait for amber. In fact the sun is so strong I can't help but get amber. I notice the high is always more complex and deep and not couchlocked at all. The high and taste and oil levels all seem to increase with proper ripeness - I look for the trichome necks to bend a little in addition to looking for color change. Last year the Santa Ana winds came through here as one of my plants was left outside finishing up. Humidity levels dropped to single digits, I noticed a slight increase in frostiness as she was finishing.
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  4. right that's why UVA and UV-B Light makes the plant make 20 to 30 percent more resin …...
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  5. When I went on vacation this year my plants went 10 days without watering, big mistake, but I didn't have anyone to do it for me, mainly because where I am the less people in the loop the better. when I got back they were all severely wilted, except for clones that were recently put in their big pots, they were totally fine. When I got home I watered with aloe 1/4 cup per gallon of water till run off, I did this 3 times in two days, they all came back with a lot of dead /yellowing leaves and they will get droopy if I don't water every other day, right now they are in their 3rd week of flower, I went to the 3rd day of no water and they went droopy yesterday, but I noted that the leaves directly adjacent to the tiny buds did not droop. I still have to finish that article, but it seems like the plant uses the energy stored in the leaves during drought to survive during veg.
    So these plants are prime for this experiment, the question is how much stress is too much, how often do I let them dry out etc. Hopefully the article will answer these questions. Thanks Scoobie
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  6. I too have found that stressing plants opens them up for invasions from pests. There must be a fine line between stressing just enough to boost trichome production, but not enough to invite pests to the plant. I am not so sure, the trade off is worth it, especially for outdoor growing.
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  7. I still haven't seen anything science based to support this theory. Has anyone. The only scientific studies that I have seen (they were posted here at GCO) using UVB on other crops, showed that the addition of UVB stressed the plants and made them more suceptible to insect damage. Again, I wonder if the risk is worth it. I do add uvb, so I'm not a hater, just curious if anymore studies have surfaced with regard to uvb light.
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  8. Your using UV-B light in the last ten days of the plants life ,, there isn't a chance for the bugs to get to the plant if the plant is still healthy in the last ten days .
    Most everyone runs their Solar storm lights semi continuously or like 15 minutes on 15 minutes off
    or they leave them on for 4 to 6 hours straight .

    I have mine on a timer cycler one minute on 15 off .

    If you haven't found any research on this then you haven't looked .
    When you have control over the light spectrum of your grow lights, you have the ability to tell your plants how to grow, how to flower, and how much resin to produce. This is why we highly recommend using LED light. Grow lights like these give you variable spectrum control, versus the old-school method of just switching out an MH (blueish) bulb for an HPS (reddish) bulb.

    In order to get more potency in the flowering stage, you want to inspire your plant to produce more resin-producing trichomes. You do this by cranking up blue, white, and UVB lights to 100% and backing red down to around 50%.

    Why does that work?

    Plants produce trichomes protectively. In nature, these little guys use trichomes and the resulting resin as a sort of buffer against the sun’s UVB rays. The better you can mimic that light in your grow room, the more trichomes you’ll get and the better shot you’ll have at reaching maximum potency.
  9. According to new studies, they suspect the origin of cannabis was on the Tibet Plateau. Dry environment. I have several landrace strains that cannot tolerate humidity levels above 40%.
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  10. The last 10 days only is something I haven't seen before. I typically use UVB for 1/2 hour intervals a few times a day all throughout flower.
    Not hating, but all the links are just ads not anything scientific. I have been searching for something with a control group and a uvb group in a study.
    For the record, I am a long time LED user, builder, and advocate.
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  11. Hey guys thanks for chiming in. Yes it is a known fact that stress can help the plant in many ways, one of which is encrease in its defense mechanisms, or in out case, the increase in cannabinoid and/or terpine production. It is one of the reasons we like to apply Aloe because it activates a plants SAR system.

    I would like to however steer this conversation more specifically towards how controlling RH can help stimulate these mechanisms (increased trichome and resin production) in the plant.

    The UV discussion is interesting in by itself no doubt, but I think it should have its own thread. Unfortunatly, AFAIK there is hardly any scientific data out today to really warrent a discussion at this point.
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  12. Ah that is interesting. As mentioned earlier im sure genetics plays a big role in this as well. Cannabis has been breed indoors for decades and certainly its possible that some of the strains gained a tolerance to high humidity, or alternatively were breed to produce more tricomes regardless and so humidity might not even effect them anymore in that regard (since they are already maxing out thier trichome developement potential).

    Just curious, which landrace strains have you noticed this lack of tolerance for humidity with?
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  13. #13 Headhunterpipes, Sep 2, 2019
    Last edited: Sep 2, 2019
    Removed research
  14. Well WTF I was doing research and making a response while you posted this ..
    Sorry If I would of seen this post before I posted my reply I wouldn't of posted .

    I will delete .
  15. Mostly landrace strains from Iran, Turkey, Lebanon, etc...
    But I have noticed better quality from my other hybrids if I keep the humidity low, temps high and a light hand when watering.
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  16. Sorry I didnt mean to come off as rude, that was not my intetion. I just know these conversations can get sidetracked very easily and I really want to discuss the topic at hand (humidity). However I would love to see any research or info regarding the use of UV ligth, I have some myself in fact but have yet to come to any conclusions weather it helps or how much it does. If you do have anything to share on the subject I think it would be a very interesting subject to start a thread about, or you could PM me the links and i could start one.
    Again, I hope I didnt offend it was not my intention.
  17. Interesting. Did you notice any change in potency or terpin quality/profile using drier environment?
  18. I have noticed the taste and smell are better, but I have not done a side-by-side comparison grow to test the potency. I'll have to do that this coming winter.

    I have noticed that they are sticky af when you run a drier environment.
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  19. My first thought is that Smokey hit the nail right on the head with regards to using the VPD chart during veg, and dropping the chart for lower humidity during flower.
    That all holds up well if we are considering landrace plants from the desert in there original form.
    Once we begin the selective breeding process, for example what the guys on the west coast have been doing for half a century things get a little more muddy in my mind, and not quite so straight forward.
    This is what I think. As we have been selectively breeding plants that grow well in humid environments, like the Pacific Northwest, we have been searching for plants that perform the best in those environments. I think that in most cases, trying to get something out of a plant, in conditions other than which she has been selectively bred to perform the best, is a losing proposition. Its right along the lines of what @PoiBoy79 and Smokey were alluding to. I would think you might get lucky once in a while, but overall, you should grow the best plants in the conditions in which they were selectively bred.
    I would prefer to grow healthy plants, just cause its easier and the success rate is higher.

    But if you were going to drop humidity during the trichome production stage of a plants life, what would be the right time? And if not at the end of flower, for how long of an interval?
    My first guess would be not to just go to a low RH level, like 40% at 80'F for flowering.
    I would think a more natural daily cycle would make more sense. If you could maintain a good VPD for part of the day, then drop to low RH at mid day, and gradually return to good VPD you might get the best of both worlds.
    You could accomplish maintaining a healthy plant, while just stressing it and 'turning the tables' on VPD for a period of time each day. Where I live, this happens naturally in the summer. It is at this hottest driest part of the day, that the plants really stink. To me, this is a good indication they are stressing. For photo plants, you could maintain a good VPD # and then drop RH for 4 hours in the middle of the day, and then bring it back up to a good VPD #.
    I suspect that a lot folks do this unintentionally already to some extent. Think about it this way. If you maintain a decent night temperature and humidty, your lights come on and the room begins to heat up. Unless you are adding humidty, the humidity % should drop as the temp increases. There you have your transition into low RH, and hopefully more trichome production. At lights out, the temp drops, and the humidity returns to a decent number. Its my gut feeling that using an environmental control, to return the plant to a happy VPD for a few hours before night would be the best for the plant, like happens in nature.

    What do ya all think of that?
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  20. very interesting concept.
    I would think that anything that is mimicking nature could be going along the correct path. That immediately than brought up the question in my mind of your currently preferred 24/0 lighting schedule. Your theory relies on that light on/off cycle, which the guys running photo-period plants are already getting. For the Auto cultivars, that would mean going down to something like 20/4 or 18/6 to give the environment a chance to settle down to the different temp/rh level, stress the plant for a number of hours, than light cycle changes back. I suppose experimenting at that point to see if changing the number of lights out hours makes a difference good or bad, whether it's 4hrs, 6hrs, or what?

    when you say your plants stink the most during the hottest, driest time of the day, I agree and notice the same as I'm sure all probably do. Interesting you indicate that as a sign of stressing. This very well may be correct. Not ever having any information to the contrary I actually always kinda figured the increased aroma on hotter days were from from of the plants terpenes starting to "cook" or vapor off. I thought I read somewhere that many of the terpenes can start to vapor off at temps as low as around 70-72f. Since most peoples grow environments tend to run around 8-10f above that with lights on I always associated the aroma from vaporing off of terps.
    hmmm, maybe once it reaches a temp where the plants terps are getting vaporized is what IS stressing the plant??
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