Cannabis, a plant with high medicinal and recreational value, relies heavily on environmental conditions, especially the photoperiod, for its development.
Traditionally, cannabis plants are cultivated under a 12 hours of light and 12 hours of darkness (12/12) regimen to induce flowering.
However, recent studies, such as that from University of Guelph titled "Longer Photoperiod Substantially Increases Indoor-Grown Cannabis' Yield and Quality", have shown that extending the photoperiod can significantly improve the yield and quality of cannabis.
This experiment aims to investigate the effects of a 13 hours of light and 11 hours of darkness (13/11) photoperiod compared to the standard 12/12, in a traditional cultivation setting.
We will assess its impact on resin production, cannabinoid content, and floral morphology.
In addition, advanced lighting techniques such as infrared (IR) light will be incorporated to stimulate plant growth.
This experiment aims to evaluate how extending the photoperiod can
increase flower production by 30% to 50% in certain strains.
If confirmed, this advancement could revolutionize cultivation at different levels.
For home medicinal cultivators, it would mean higher yields and quality without significant additional infrastructure investment.
For medical cannabis clubs and industrial producers, it opens up possibilities to optimize production in the same spaces and reduce costs, increasing access to high-quality flowers.
This research has the potential to bring significant changes to the industry, making cannabis cultivation more efficient and accessible, with both economic and product quality benefits, bringing medicinal cannabis closer to those who need it most.
MADE IN ARGENTINA
We would like to express our sincere thanks to INASE Argentina (National Seed Institute) for granting us permission to work as plant breeders, enabling us to carry out this experiment and our research on polyploidy and male plant reversal.
This permission has allowed us to carry out this pioneering study, contributing to the advancement of knowledge on cannabis cultivation under different lighting conditions.
We highly value their role in regulating these projects, which are essential to the evolution of the medicinal cannabis industry in the country.
We also extend an invitation to INASE to collaborate in the dissemination of the results obtained in this experiment.
We believe that their participation in sharing these scientific advancements could positively impact the community, providing key information to producers and patients.
Together, we can contribute to the growth of a more informed and responsible industry.
The paper we are using as a basis for this experiment hypothesizes that a 13/11 photoperiod will allow for longer photosynthesis time, resulting in increased floral biomass and resin production, as well as a higher concentration of cannabinoids without compromising final product quality.
This study will also evaluate how infrared (IR) light during the night period may induce elongation responses in the plants, further optimizing yield.
Experimental Design Indoor for Comparisons
| Area | Photoperiod | Description |
|---|---|---|
| 🌱 Area 1 (12/12) | 12 hours light / 12 hours darkness | Standard cycle used to induce flowering. |
| 🌞 Area 2 (13/11) | 13 hours light / 11 hours darkness | Moderate increase in light hours. |
| 🌅 Area 3 (14/10) | 14 hours light / 10 hours darkness | Evaluation of the effect of a prolonged light cycle on resin and biomass production. |
| 🌌 Area 4 (13/11 + IR) | 13 hours light / 11 hours darkness + Infrared Light | Use of IR light (850-940 nm) during the dark phase to induce stem elongation. |
In all spaces, a vegetative phase with 24 continuous hours of light will be maintained before switching to the described flowering cycles.
This technique aims to shorten the total cultivation time without compromising plant development.
30-Day Timelapse
As of 31/10/2024, the 12/12 and 13/11 photoperiod comparison trial has reached the mid-stage of its flowering cycle, currently totaling 31 days in this phase.
To evaluate developmental differences across lighting regimes, we present a comparative timelapse illustrating the current state of each cultivation space.
Upon completing the full flowering cycle in all spaces, including the 14/10 photoperiod space (which develops more slowly), a detailed presentation of the results will follow.
This final phase will include a tasting conducted together with the breeders responsible for each strain and the companies participating in the project. Additionally, we will conduct a comparative analysis of the total yield in terms of biomass (weight) and production density (number of flowers), providing both quantitative and qualitative insights for each strain.
Cannabinoid content and other active compound analyses will be provided by IACA Laboratories, enabling a precise and scientific evaluation of the effects of each photoperiod on cannabis production and quality.
Phytochrome and Light Responses
The phytochrome, a light-sensitive pigment, regulates the flowering cycle of plants according to the amount of light and darkness they receive. This pigment exists in two forms:
1. Pr (inactive form), which is activated in darkness.
2. Pfr (active form), which is activated by light.
During the flowering phase, what really matters is the ratio between these two forms at the end of the light cycle. When plants receive more hours of light (as in a 13/11 or 14/10 cycle), the Pfr form remains active for longer. This delays the signal to begin flowering immediately, allowing plants to accumulate more biomass and energy before entering the full flowering stage.
This delay in flowering does not mean the plant reverts to the vegetative phase; rather, it has more time in the floral development phase to produce larger, more resinous buds. Thus, greater light exposure encourages more robust flower growth, potentially increasing yield at the end of the cycle.
Photoperiods and Genetics
Cannabis, in its indica and sativa forms, has evolved in regions with different daylight durations, influencing its ability to adapt to various photoperiods. Indicas, originating from mountainous areas like the Hindu Kush, have developed sensitivity to shorter days, a characteristic of cold climates where winter arrives quickly. These plants evolved to flower rapidly, taking advantage of the short window of light available before temperatures drop too low.
On the other hand, sativas, native to equatorial regions such as Thailand or Colombia, are adapted to long days throughout the year.
These plants require more hours of light to flower since their natural environment provides intense and prolonged sunlight. Consequently, the development time for sativas is longer, allowing them to produce larger amounts of biomass and often higher levels of cannabinoids.
This process of adaptation to photoperiods has been manipulated by breeders who have crossed indicas and sativas to create hybrids that combine the best characteristics of both, optimizing the life cycle and resin production.
These hybrids have intermediate light sensitivities, meaning they respond more flexibly to photoperiod variations.
In the proposed experiment, the extended photoperiods of 13/11 and 14/10 allow us to leverage the adaptable nature of these hybrids. The varieties used (indica-sativa hybrids) can benefit from these additional hours of light, extending flower development time without compromising the flowering cycle. This is especially useful in indoor cultivation, where precise light manipulation can optimize plant yield in terms of both biomass and cannabinoid production.
Therefore, by extending the photoperiod in this experiment, we aim to harness the phenotypic plasticity of these hybrids, which respond favorably to increased light hours, resulting in higher yields without significantly affecting harvest times.
This demonstrates how genetic evolution, combined with photoperiod manipulation, can be a powerful tool in optimizing cannabis cultivation.
Resin and Cannabinoid Production
Based on previous studies, the 13/11 and 14/10 photoperiods are expected to result in an increase in floral biomass and resin production.
In particular, an increase in THCA concentration is anticipated, similar to the results observed in the University of Guelph study, where THCA increased by 10% under an extended photoperiod.
Infrared (IR) Light Responses
Infrared (IR) light applied during the nighttime phase in Space 4 of this experiment is expected to have a specific impact on stem elongation without interrupting the flowering process.
This technique is based on the plant’s perception of light, particularly how it interprets light in the 850 to 940 nm range, which is not used directly in photosynthesis but acts as a shade signal.
Plants perceive this near-infrared spectrum as an indication that they are being shaded by other plants, triggering a physiological response known as "shade avoidance response."
Mechanism of Action of Infrared Light
When the ratio of far-red light (FR) to normal red light increases (simulating a shaded environment), the plant detects this difference through phytochrome and responds by elongating its stem and increasing the internodal distance. This adaptive behavior allows the plant to "escape" the shade of its competitors by stretching towards the light.
Related Studies in Other Plants
Although this technique has not been widely documented in cannabis, studies in other plant species, such as Arabidopsis thaliana and agricultural crops like tomato and cucumber, have shown that near-infrared light induces stem elongation and modulates plant architecture without negatively affecting fruit production. In these studies, near-infrared light was applied at night, allowing the plants to experience controlled elongation without reducing their photosynthetic performance during the day.
Expectations in Cannabis
In the context of cannabis, near-infrared light applied during the nighttime phase is expected to induce moderate stem elongation, which could be beneficial for increasing plant height without compromising flowering. This additional stretch could allow greater light access for lower leaves and improve ventilation between branches, reducing the risk of moisture buildup and diseases such as mold.
Lateral Light Reinforcement
This treatment will be complemented with lateral light reinforcement during the daytime light cycle.
The combination of both approaches is designed to improve light distribution throughout the plant, particularly in the lower parts that normally receive less light.
The goal is to increase total biomass without affecting the quality of the cannabinoids produced, as cannabis may respond similarly to other species by increasing plant structure while maintaining or enhancing resin and secondary metabolite production.
In summary, although there are no specific studies on the use of near-infrared light in cannabis, extrapolation from studies in other plants suggests that this technique can have a positive effect on plant architecture without compromising cannabinoid yield, allowing for greater biomass development without affecting the plant’s chemical profile.
Cannabinoid Analysis
Detailed analyses of cannabinoids and secondary metabolites will be conducted in collaboration with specialized laboratories such as @iacalaboratorios. These analyses will allow us to compare the final product quality in each treatment.
Sensory Evaluation
At the end of the cultivation cycle, a tasting will be conducted with the trial participants to assess whether changes in lighting environments affect the perceived aroma, flavor, and effects of the product.
This experiment has the potential to provide new insights into how precise photoperiod control and the incorporation of advanced lighting techniques can significantly improve the yield and quality of indoor-grown cannabis. The results of this study will be published on supercannabis.ar, aiming to contribute valuable knowledge for medicinal cannabis cultivation.
Genetica Yeti
Harambe
Monitoreo y control Growcast.io
Quantitative Cannabinoid Profile: Detection and quantification of cannabinoids in dried flowers by HPLC-UV - high-performance liquid chromatography with UV detector.
The profile will report the concentration in mg per gram of 11 cannabinoids.
Quantitative Terpene Profile: Detection and quantification of terpenes in dried flowers by GC-FID - gas chromatography with FID detector.
The profile will report the concentration in µg (microgram) per gram of 20 terpenes present in the flower.
