The Medical Cannabis industry surely has come a long way, from passionate patient driven home growers to contemporary large-scale cultivation, either carried out indoors, outdoors, or in greenhouses. “The industry is finally regulating itself” says André Lagareiro, International Account Manager for Medical Cannabis projects at Hortilux, bringing extensive knowledge on cannabis genetics and how different light spectra can affect plant growth. “Nowadays, growers can choose the most suitable infrastructure to grow cannabis at scale. Of course, depending on what the end product would be, a specific facility is more suitable than another. At the same time, greenhouses represent one of the most interesting methods for the combination of technology and sunlight they offer.”
Cannabis under full spectrum LED
André further explains his approach to cannabis greenhouse growing. “There is a thing I call ‘a circle of 5’, which is: Co2, humidity, irrigation/fertigation, temperature and light,” he points out. “Understanding and controlling as many of these factors as possible is what ultimately influences yield and quality. For instance, we can supply double the amount of light needed, but if you don’t combine that with the right amount of CO2 and nutrients, for example, the plant won’t have the ‘ingredients’ to metabolize all that light. Same thing goes for the other elements: if you get most of them right, but humidity is too high, then you still run the risk of pathogen outbreaks.”
At the same time, André says that he is hopeful for the future of medical cannabis cultivation. “Techniques once applied to large-scale vegetable and cut flower cultivation are now being brought and adapted to growing medical cannabis,” he remarks. “We have a lot to learn from horticulture in order to succeed in large-scale cultivation. For example, the methods described in the Growing by Plant Empowerment philosophy, are now also being tested on medical cannabis crops, with fantastic results.”
Choosing the right lighting system
According to André, growing medical cannabis to its full potential is a fairly complex task that requires experience, flair to read the plant and optimal condition provisioning. “For instance, when choosing a lighting system for a specific project, we at Hortilux look into as many conditions as possible: external, internal, desired product quality standards, energy consumption/cost, investment capacity, and so forth” he points out.
“Growing in a greenhouse is a completely different ‘beast’ than growing indoors, as the latter allows for more granular control, making cultivation more manageable. Depending on the type of greenhouse and its location, one is much more at the mercy of natural elements, but also, these can be used to our benefit. For instance, a greenhouse located in Southern Portugal or California gets a good amount of sun radiation, thus providing opportunities to engineer the lighting system so that it utilizes that ‘free’ light, to get maximum results in a cost effective way. At the same time, this poses some challenges, such as keeping the temperature low enough in the summer, or the right humidity levels. Hortilux has both HPS and LED solutions that can be used solo or combined to achieve the best results for specific product and infrastructure needs. As you can tell, lighting is a very complex matter. That is why we not only provide the lighting system, but also offer advice and consultancy services to growers, to make sure that they achieve the highest efficiency and best results.”
HPS vs LED
As of today, the cannabis industry is slowly shifting towards LED as the technological advancements provide new opportunities, both in full-LED as well as Hybrid installations with the traditional high-pressure sodium (HPS) lights. “High-pressure sodium has been the standard for years,” André says. “And as the saying goes, you don’t change a winning team. HPS has a rich spectrum but produces a lot of convex heat and IR radiation, as well requiring more power than LED. LED allows for specific spectrum formulas to be brewed and combined; it is much more efficient in the energy conversion, and the heat print is much lower and manageable. However, we look at every client’s specific situation to decide what the best solution is (Full-LED, HPS or Hybrid), depending on long term goals, locals growing conditions, investment... This is especially important nowadays as the cannabis industry is particularly energy-intensive, and therefore it is crucial to address the sustainability of one’s operation."
Different light spectra and cannabis genetics
André has worked for many years for a seed bank, and therefore he is very much aware of how specific genetics are more susceptible to certain light spectra. “Depending on genetics, the light spectrum can positively influence how a plant grows,” he says. “For example, there is evidence that subjecting a short Indica strain to a reduced amount of blue light, and the right red/far-red ratio during its vegetative phase, can potentially increase the spacing between the internodes, thus allowing for flowers to have more space to develop, and ultimately increasing yield. Several test results have come out analyzing the impact of light spectrum on cannabinoid and terpene production, and proper LED systems have been shown to outperform their HPS counterparts. All in all, the different stages of the plant growth require different spectra to mimic the ideal condition it would get in nature, even specific to the region where its genes originate from.”
“We are only at the tip of the iceberg here,” he observes. “As Brendan Kennedy, CEO of Tilray has stated, we are in the ‘prototyping phase’ of the cannabis industry. There is so much we can and still have to learn. These are very exciting times, now that the cannabis industry is regulating itself and cross-disciplinary ingenuity is helping to push our knowledge to higher exponents.”