Hit em with several UVB bulbs last several weeks & cut back on H2O…lower humidity to <35%, they’ll wish they had sunblock…they do
Trichomes!!!
Proven to increase THC not CBD, etc.
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MaximumYield
“Like just about everything else on planet, cannabis plants are damaged by too much UV light. That’s why a cannabis plant will create more trichomes to protect itself if there is an increase in harmful
UV-B rays. As such, supplementing UV-B light using UV-B fluorescents (commonly sold at pet stores for reptiles) in a
flowering room can help boost trichome production, 2 power draw watts per sq/ft.)
OR
Article:
Horticulture •
Techniques
Cannabis Under Stress Produces More THC
April 3, 2020
Quote: UVB works
Another example is ultraviolet-B (UV-B) radiation, which can easily destroy plants in sufficient quantities. But in small amounts during flowering, UV-B light boosts THC accumulation in cannabis, an act of self-protection reminiscent of sunscreen. [2,3]
Mansouri et al [4] applied
abscisic acid (ABA), a sesquiterpene that acts as a plant hormone, to flowering cannabis plants. ABA inhibits growth and is produced by plants in response to environmental stressors, including (but not limited to) drought, UV radiation, cold, and salinity. [5] After exogenous application to cannabis, the researchers noted increased THC and α-tocopherol but decreased chlorophyll, carotenoids, and phytosterols. [4]
&
One recent study applied controlled drought to flowering cannabis plants. [1] The researchers withheld
fertigation for 11 days starting at week 7 of the flowering period. This increased tetrahydrocannabinolic acid (THCA) by 12% and cannabidiolic acid (CBDA) by 13% compared to the well-irrigated control. THC and CBD yields per unit growing area were 50% and 67% higher, respectively.
And finally a goody study done yrs ago:
UV-B RADIATION EFFECTS ON PHOTOSYNTHESIS, GROWTH AND CANNABINOID PRODUCTION OF TWO Cannabis sativa CHEMOTYPES
JOHNLYDON~.A*L, ANH. TERAMUaRnAd 'C. BENJAMICNOFFMAN~ 'Department of Botany, University of Maryland, College Park, MD 20742, USA,,2USDA-ARS, Southern Weed Science Laboratory, P.O. Box 350, Stoneville, MS 38776. USA and 'USDA-ARS,
Weed Science Laboratory, AEQ. I, Beltsville, MD 20705. USA
(Received 29 August 1986; accepted 24 February 1987)
Abstract-The effects of UV-B radiation on photosynthesis, growth and cannabinoid production of two greenhouse-grown C. sativa chemotypes (drug and fiber) were assessed.
Excerpt: “Only capitate-sessile and capitate-stalked glands contain cannabinoids, with stalked glands containing > 7 times more cannabinoids than sessile glands (Mahlberg et al., 1984). Capitate-stalked glands are only present on bracts (and associated leaves), cover over 70% of the surface area of bracts, and contain 100% of the cannabinoids in these tissues (Mahlbert et al., 1984). Thus, the UV-B absorbing cannabino- ids may be important in preventing this actinic radi- ation from penetrating ovary tissues. If so, populations of C. sativa which express UV-B enhanced cannabinoid production (as demonstrated with the drug chemotype) may have more repro- ductive success in high UV-B radiation environ- ments. This may account for the distribution of these chemotypes in temperate and tropical environ- ments as reported by Pate (1983). It should be pointed out, however, that one should be cautious when extrapolating from greenhouse to field con- ditions in UV-B studies. In addition, when consider- ing the distribution of C. sativa, one cannot overlook the fact that it is one of the oldest culti- vated plants known to man. Thus, its present distri- bution may possibly be an artifact of man’s cultural practices.
In conclusion, the A9-THC content in leaf and floral tissues of greenhouse grown drug-type C. saliva increased linearly with UV-B dose”
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Here I MO our humidity is terrible six months out of the year, so I finally bought a dehumidifier for my flowering stage.
These are the UVB bulbs I use—I’ll runner four of them and Dual bulb hangers, about 12” from plants moving them daily for exposure.
UVB 150W $26 @Petsmart.
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