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Old 01-04-2019, 11:26 PM
Efesto's Avatar
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Posts: 169

for those interested,
the study posted above is part of a monograph entitled:
Propagation and Root Zone Management for Controlled Environment Cannabis Production


Cannabis producers lack reliable information on the horticultural management of their crops. This thesis research was designed to improve horticultural practices for controlled environment cannabis production; topics included propagation, growing substrates, fertilization, and irrigation. To optimize the procedures for taking vegetative stem cuttings in cannabis, several factors were evaluated on how they affect rooting success and quality (Chapter Two). These included number of leaves, leaf tip removal, basal/apical position of cutting on the stock plant, and type of rooting hormone. Removing leaf tips reduced rooting success and cuttings with three fully-expanded leaves had higher rooting success and quality than those with two. Also, a 0.2% indole-3-butyric gel was more effective than a 0.2% willow extract gel to stimulate rooting and cutting position had no effect on rooting. Coir-based substrates with different physical properties were evaluated during the vegetative and flowering stage of cannabis production; optimal organic fertilizer rates were established for each substrate (Chapters Three and Four). During the vegetative stage, cannabis performed well in both tested substrates despite the ≈11% difference in container capacity (CC) between them. During the flowering stage, the substrate with lower CC increased floral dry weight (yield) and the concentration and/or yield of some cannabinoids, including THC, compared to the substrate with higher CC. The optimal organic fertilizer rate varied by substrate during the flowering stage but not during the vegetative stage; higher fertilizer rate during the flowering stage increased growth and yield but diluted some cannabinoids. Finally, the effects of controlled drought stress timing and frequency during the flowering stage were explored on floral dry weight and secondary metabolism (Chapters Five and Six). When drought was applied during week seven of the flowering stage, through gradual substrate drying over eleven days, floral concentration and content per unit growing area of major cannabinoids were increased. When drought was applied over a period of ≈8 days during week seven, cannabinoid content was similar to a well-watered control; though, dependent on drought timing, the content of some terpenoids varied. This research provided evidence-based information that can help growers improve the quality and yield of their cannabis crops.


vivere tota vita discendum est et, quod magis fortasse miraberis, tota vita discendum est mori.

Last edited by Efesto; 01-04-2019 at 11:43 PM.
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Old 01-24-2019, 05:24 PM
Join Date: Feb 2011
Location: michigan
Posts: 1,814

thanks for posting these trials.
i found both to be interesting.

i have had 100% success with clones for a while, but i use aero type cloners.
i do tear the leafs somewhere between 50-75% and usually just leave two leaves.
i do not use a dome at all.
so maybe the drier environment is counteracted upon by having less surface area for evaporative stress. if you did not have this issue, then it makes sense that more leaf area/photosynthesis would produce better results.
Ill give it a try next time and see if i notice any difference.
sometimes i see roots starting to come off the stem at 7 days, but it usually takes until 14 days until i feel they are ready for transplant.

it is really interesting that the drought does reduce the photosynthetic rate, yet somehow the yield is unaffected and the cannabinoids are increased. i guess the increased resin content may make up for reduced plant growth to end up at the same end dry weight. otherwise if the plants grew the same and the drought stricken plants had more resin, they would weigh more.
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Old 01-24-2019, 08:18 PM
Marcus_in_the_Darkus's Avatar
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Join Date: Mar 2017
Location: Legal in Massachusetts
Posts: 1,130

Thank you, Efesto, for bringing the tech in this thread.
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Old 01-29-2019, 08:51 AM
Broseidon's Avatar
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Join Date: Nov 2015
Posts: 921

Thank you Efesto for sharing with us!

Wish I had taken the time to read it before I cloned xD

Next time I will not cut the leafs and see how it goes.

For me the biggest difference so far though seems to be my new DIY aero cloner vs. my past methods of cloning in jiffy plugs or rock wool.

The clones in the aero cloner look completely green and healthy a week after being cut (no roots yet though) while the ones in jiffy plugs and rockwool always started to yellow/have leafs dying off.

But I always wondered which leafs to leave on the clones. I usually left 4 leafs, i.e. 2 nodes but was never sure if I should cut the 2nd one or not because it always died off within a week or two after cutting (unlike in the aero cloner).

Anyway, good info!
Also nice to know that the spot where one makes the cut and how the cut is made is not important/deciding factor. Used to obsess about that and always try to change my cutting technique, trying to get better with the scalpel.
Now I can relax with that
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