[Douglas.Curtis]

IME, Low Humidity, Low Temperature flowering environments, for cannabis, produce higher trichome density.

I've been able to find a few pieces of information pointing in that direction as well. The difficulty is in finding studies done with high VPD, low humidity environments. The only one I found is the link below about cucumber plants. The trichome differences in the study match my own experiences.

The other links have only bits and pieces which are close.

Anyone willing to do some more research, I welcome the help. I'm limited to free content from google.

https://faculty.unlv.edu/landau/adaptations.htm
Under 'Other Adaptations'
c. Trichomes reduce heat load, reduce leaf temperature, reduce transpiration rates, reduces photosynthetically active radiation (negative effect), by absorbing and reflecting infra-red radiation.
[Specifically the production of additional trichomes to reduce transpiration loss]


https://www.ncbi.nlm.nih.gov/pubmed/26511981
3 humidity levels used to sprout cucumbers. lowest rh with highest vpd produced highest levels of trichomes.

We conclude that oviposition was accelerated under low humidity (high VPD) conditions indirectly, probably through an increase in the trichome density of host leaves.

Robert Clark Marijuana Botany
Cannabis seems not to produce more resins in response to dry soil, as it does to a dry atmosphere. Drying out plants by with- holding water for the last weeks of flowering does not stimulate THC production, although an arid atmosphere may do so. -

https://benthamopen.com/contents/pdf/...RMCJ-5-146.pdf
Roy et al. found that Sinapis arvensis might increase trichome density to decrease water loss under drought [58]

https://www.icmag.com/ic/showthread.php?t=328208&page=4
Mile High's posts confirm what I've seen, as far as healthy plants in low humidity. I don't do teas and don't see the tacoing his photos show when he does use teas.

Thank you,

Douglas

[Coughie]

This gets a little more complicated because there are several types of trichomes on cannabis plants... The ones we want have bulbous heads, on stalks... But there are also headless stalks and stalkless heads...

So not only would we have to look into whether or not it increases trichome production - but also, what type of trichome is it increasing the production of?

Also should be noted that this is going to be highly-tied to genetics, with the plants themselves having upper and lower thresholds for trichome production.. So how would we know when we've hit that threshold for that particular plant, and attempting to push it higher is a limitation of the plant and not an error in the experiment?

Just food for thought..
I don't have time to dig around at the moment, but am interested in any progress

[Douglas.Curtis]

I appreciate the feedback.

Originally Posted by Coughie

This gets a little more complicated because there are several types of trichomes on cannabis plants... The ones we want have bulbous heads, on stalks... But there are also headless stalks and stalkless heads...

So not only would we have to look into whether or not it increases trichome production - but also, what type of trichome is it increasing the production of?

Excellent points. I've noticed the type of trichomes produced to be more genetic, I have no photo comparisons to verify any differences in ratios, due to humidity changes. IME the end effect is massive terpene retention and cannabinoid potency, over higher humidity and heat environments, in addition to visibly increased trichome density.

Originally Posted by Coughie

Also should be noted that this is going to be highly-tied to genetics, with the plants themselves having upper and lower thresholds for trichome production.. So how would we know when we've hit that threshold for that particular plant, and attempting to push it higher is a limitation of the plant and not an error in the experiment?

This is why I'm looking for studies using the same genetics, in different flowering environments. The cucumber plants show exactly what I expect from cannabis. It's also the only study done with 3 completely separate grow environments. All high VPD, all medium to low humidity.

Strain for strain, compared with results of local growers and dispensaries, every strain/phenotype has come out visibly more dense. Definitely more terpene production, it makes sense from the sheer power and complexity of the flavors and aromas.

I also grow cleanly, which makes a big difference, yet this does not account for the trichome density. I use no boosters or additives for boosting production.

Douglas