Light Spectrum in Cannabis, pursuing the right recipe


Light Spectrum in Cannabis, pursuing the right recipe

Cultivating Cannabis sativa L. (Cannabaceae) differs from other horticultural plants by the end product that is harvested. The total yield is inspected not only by its weight of the flowers but also by the chemical composition. Different cannabis chemotypes contain numerous chemical compounds, such as cannabinoids, which are known to exert various pharmacological effects.


Fotonica R&D lab, Israel 2019


Morphology and cannabinoid profile are dependent on genetic and environmental factors. For a medicinal cannabis producer, a consistent yield and production of a specific cannabinoid compounds or a ratio between the different cannabinoids throughout the canopy and between growth cycles is important. The solution lies in moving from greenhouses (outdoor) to indoors, controlled environments there, it is possible to adjust temperature, humidity, light intensity, light spectrum, air CO2 concentration and pest management improves as susceptibility is reduced. Indoor cultivation offers the ability to cultivate year-round with stable conditions that may result up to 6 harvests per year. This makes indoor cropping 15–30 times more productive than outdoor cultivation [UNODC: World Drug Report 2009]. In addition, indoor production minimizes the risk of cross-pollination and guarantee flowers without fertilization or seed maturation.

One of the most important growth factors in cannabis cultivation is light. Light quality, light intensity, and photope­riod play a significant role in a successful growth. While in older technologies, such as HPS or fluorescent light, that has been originally developed for street or office lighting the spectrum is seldom adjusted according to the plants’ needs, we in Fotonica refer to the light like any other cultivation input. Plants with different biomass and/or different phenological stage are not treated the same, for example irrigation (volume, interval, timing etc.) or fertilization (concentration, composition etc.) same should capture for the light.

Plants have specific wavelength antennas (photoreceptors) which receives signals from the environment light, the major ones are:

  • Phytochromes – red & far-red-sensing photoreceptors (regulates flowering, shade avoidance syndrome behavior, and germination in many species).
  • Cryptochromes – blue & green wavelengths sensing
  • Phototropins – blue & green wavelengths sensing
  • UVR8 – responsible for UV-B-induced responses

It has been long known that one can manipulate plant morphology and metabolism with the light spectrum, for example:

  • Blue – decreases internode length and enhance compactness of various species.
  • Far-red & Green – induce shade avoidance syndrome symptoms, including stem and leaf elongation and premature flowering.
  • Red & Blue – plants had shorter internodes and a smaller leaf area compared to a white light source.

In addition to morphological changes, light spectrum and ir­radiance level also have an impact on plant metabolism.

  • Short wavelength irradiation has been shown to enhance the plant defense mechanism by inducing metabolic activity, such as phenolic compound synthesis. Phenolic compounds, including antho­cyanins. Several cannabi­noids have also been suggested to be involved in the plant defense mechanism and to have antioxidant properties, including Δ-9-tetrahydrocannabinol (THC) and canna­bidiol (CBD) (Hampson et al. NY Acad. Sci. 2000), as well as cannabigerol (CBG) (Giacoppo et al. Eur. J Histochem 2017).
  • Increased concentrations of THC, were found with UV-B supply in both leaf and floral tissues of drug-type plants (Pate DW: Chem. Ecology of Cannabis. J Ind Hemp Assoc 1994). UV-B may be related to stress induction mechanism which is leading to different molecules production as a respond.

Fotonica EVA3 system is offering fully flexible integrated spectrum curve with 11 bands from UVB/UVA to Far Red/IR (DLED – Dynamic LED system). In addition, light modulation can be performed inclusive of adjustable duty cycle and other light parameters.


Same system different adjustable spectrum - Fotonica technical test site, 2019


While light quality may influence the cannabinoid synthesis, cannabis yields are strongly correlated with increasing light intensity (Chandra et al. Physiol. Mol. Biol. Plants 2008). An increasing irradiance level is correlated positively with flower dry weight, which can result in higher total cannabinoid yield.

Fotonica EVA3 system is fed with power supply of >1,000 Watts enabling high accurate and uniform (special designed lenses) intensity exceeding 1,100 PPFD (1.5 M height over 4’X4’ area). Moreover, the EVA3 is converting the electrons current only to the right photons spectrum with the right intensity enabling electricity saving unlike other fixed spectrum and intensity fixtures.

It is all about Bio Illumination – Light conditions play an important role in plant morphology as well as in the accumulation of cannabinoids. During a long photoperiod, a low R:FR ratio is preferable to make more developed long cuttings, while during a short photoperiod a high proportion of blue irradiation is suitable to improve cannabinoid content (Gianmaria et al. Med. Cannabis Cannabinoids 2018). EVA3 spectrum manipulation is an advantage that offers better space utilization, human resources reduction, lesser energy consumption (less heat, better current/photon conversion), lower carbon footprint and above all higher biomass and higher cannabinoids content compared to traditional HPS and other LED non-controllable fixtures. Reported by Prof. David Meiri the EVA3 system “results showed cannabinoid concentration levels that were 20-50% higher (THC, CBG respectively) in comparison to traditional HPS bulbs that were used as control and to standard verity concentration received when grown commercially” (The Laboratory of Cancer Biology and Cannabinoid Research Faculty of biology Technion – Israel Institute of Technology, 2016). The EVA3 is offering different lighting strategies implementation through light recipes embedded in its command and control software which is communicating via Bt & wireless to single and/or endless number of units even on remote geographies. The know-how is accumulated, analyzed and improved through cloud-based data center which enables ‘Big Data’ by Fotonica biologists collected from our users community.

We in Fotonica “Unleashing Plant’s Potential” !