A short essay on droughting cannabis.
Thanks for posting this here Maritimer! I'm going to drought the Sour G only, because in case everything goes horribly wrong I still want to be able to show off how well the Chiquita Banana from WSE did the old fashioned way.
The paper has it as "Caplan" for those trying to find it online.
“The drought treatment elicited a 12% increase in THCA concentration and a 13% increase in CBDA concentration but had no effect on the concentrations of the other detected cannabinoids Drought had substantial effects on cannabinoid yield, expressed as grams of cannabinoid from floral material per unit growing area (g·m-2). In the drought treatment, THC yield was 50% higher, THCA yield was 43% higher, CBD yield was 67% higher, and CBDA yield was 47% higher than in the control.”
Who wouldn't like a 12% increase in THCa for no work at all (other than the effort it takes to
not water!)?
I was concerned that the increase in THC and CBD were a result of a decrease in the size of the buds, because if you don't water it, how can it bulk up in those final weeks. But the article states:
"...inflorescence dry weight did not differ statistically between the two treatments...These results suggested that the level of drought stress applied was adequate to stimulate cannabinoid production without reducing inflorescence dry weight for this cultivar."
so I think that means the buds weren't stunted! "Inflorescence" refers to the complete flower head of a plant including stems, stalks, bracts, and flowers.
I've seen the light! Actually I've seen the trichs build during my droughting them. Wouldn't grow without doing it. And it's free!
Free!
By 7 weeks of flowering, I typically have to fertigate daily in perlite hempy. I would likely see 50% delta LWA within 3 days.
This is my concern as well given how quickly my plants dry out in ProMix HP. I'm sure Caplan's tests were run indoors in a controlled environment, as are Maritimer's. Yesterday my plants got watered in the morning and sat in the sun with
air temps at 88ºF (I'm sure leaf temps were near 100º) and humidity in the 20s. This morning they were pretty light already.
I'm assuming that the reason I understand non of this is that it is hydroponics related?
LOL! As mentioned above, not hydro at all.
In mostly peat moss it is certain.
Thanks for clarifying that!
Since I've started the drought period, I thought I would post some reference pics. Here is how Caplan diagrams the
leaf wilt angle measurement:
And here are my lame attempts with a protractor on sagging branches!
I tried to make sure the bottom of the protractor was even with the branch, as they will sag more over time.
And for fun, I took some slightly blurry pics of the trichomes on the very top of the top cola:
And one of a random lower just to compare:
Big
to Maritimer for doing all this research and testing it on his own grows.
Now let's see how long this plant can go without water and still come back and not die! Stay tuned...