Sustainability in Cannabis Cultivation: Sun-Grown vs. Indoor Methods

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Let me first start by saying that cannabis is an evolving industry with roots in prohibition. While I think most of us have some awareness of this fact, I think it’s often overlooked as we talk about cannabis business practices (from the grow room to the board room) in the post-prohibition era.

The things we had to do during prohibition should be carefully evaluated to discern whether those practices are coming from a scarcity/prohibition mindset OR an abundance/post-prohibition mindset. Certainly, many canna-culture customs from decades of prohibition have value, and we may choose to consciously keep them around to honor them. However, other practices are simply remnants of those prohibition days and no longer serve our efforts to grow a robust, abundant, and sustainable cannabis industry. In this exploration of sustainability in cannabis cultivation, we delve into the merits and drawbacks of sun-grown and indoor methods.

Introduction to Cannabis Cultivation Methods

Cannabis is often humorously referred to as a “weed,” and in many ways, that’s what it is. In many environments, it is easy to grow and does not put great demands on the land. Indeed, cannabis is an excellent vehicle for soil bioremediation, as it will extract all kinds of pollutants, salts, pesticides, and heavy metals from the soil and thrive. 

When it comes to the cultivation of medicinal cannabis or cannabis suitable for human consumption (versus cannabis grown for industrial purposes – which is exclusively grown outdoors) there are essentially two options: outdoor cultivation and indoor cultivation. Outdoor cannabis, of course, has grown easily and abundantly in areas suitable for cannabis production, like the Pacific Northwest and the Finger Lakes region of New York, for at least the last century.

However, even in these optimal areas for outdoor cannabis growth, during prohibition, indoor cultivation was the primary way cannabis was grown, largely for security reasons. Growers were more able to keep “illegal” crops off the radar of law enforcement if they couldn’t be seen. Both approaches can produce clean, quality cannabis flowers suitable for drying, curing, smoking, or extracting oils to make value-added products such as gummies and chocolates. But which is better in terms of the actual quality of the flower and its medicinal components, and sustainability in the long term?

Understanding Sun-Grown Cannabis

Sun-grown cannabis is about as basic as growing a tomato plant. Whether you are growing from seed or clone, it is not much harder. Now, to be clear, only female plants will yield flowers rich with trichomes containing cannabinoids and terpenes, the medicinal components of cannabis flowers. Sustainability in cannabis cultivation becomes evident when we consider the low carbon footprint of sun-grown methods.

Sun-grown cannabis has a very low carbon footprint and, when done correctly, does not require much in terms of soil nutrients. The challenges with sun-grown cannabis used to be that it needed to be hidden, but as cannabis legalization takes hold, regions like the Pacific Northwest can grow large canopies with no fear of legal reprisal. In Oregon, on the hemp side, we see massive acreages of the awesome cannabis plant. On the medicinal side, we are regulated to smaller lots, but that is not because of the plant.

Exploring Indoor Cannabis Cultivation

Indoor cultivation is an approach developed largely out of necessity because of prohibition. The need to keep the plant a secret made it much more convenient to grow in garages, small back rooms, and, in some cases, warehouses, where it could be hidden from prying eyes. Indoor cultivation certainly has the advantage of environmental controls. The ability to control humidity, temperature, and CO2 levels of the room gives the cultivator a great toolkit to force the plant to produce more oil, thus increasing the potency of all the cannabinoids by oil volume. 

While indoor cultivation offers control, it poses challenges to sustainability in cannabis cultivation, particularly in energy use. Unfortunately, the significant downside of indoor cultivation is its carbon footprint. Massive amounts of electricity are needed to light the environment, and even more electricity is needed to counteract the heat from those lights and power the typically automated grow systems, such as the pumps and other equipment used to move water around.

Comparative Analysis: Sun-Grown vs. Indoor Cannabis

Outdoor, “sun-grown” cannabis has a much smaller carbon footprint than indoor cultivation. It doesn’t require massive amounts of electricity to power lights. On the water usage front, while once it was true that certain recycling systems on the indoor side could be much more water-efficient, it is now equally possible to run water recycling systems. In terms of potency, recent studies into the quality and potency difference show that outdoor flowers outperform those grown indoors. 

Now that sun-grown cannabis can be done using modern agricultural technologies, I want to pause here to explain that the myth that indoor buds are better than outdoor buds is again, a holdover from prohibition. Sun-grown cannabis during prohibition did not have the opportunity to benefit from myriad agricultural technologies. They were often hidden in areas that would not be optimal for growing the plant because cultivators valued security over the best area to farm.

While I could provide some statistics here, I would encourage you to simply Google “indoor flower vs. outdoor flower,” and I think you will find that the verdict is that sun-grown flowers have much more complex cannabinoids and many more terpenes and sesquiterpenes than indoor cannabis flowers.

In short, in a post-prohibition era when sun-grown farmers can use all modern agricultural technology and grow cannabis under the sun and in the open, we need to reevaluate whether indoor flowers are better than sun-grown flowers. When growing strain for strain, potency in indoor flowers can be forced and manipulated, but I think that now, with outdoor flowers given the same ability to control nutrients and other environmental factors, we will see the same on the sun-grown side, without the enormous sustainability challenges.

The Role of Organic and Natural Cannabis Practices

In both cases, whether you are growing outdoors or indoors, organic growing practices are available. For outdoor crops, organic practices can easily be adhered to. I think it goes without saying that like most things consumed by humans, as we evolve, they should be as clean and green as possible. 

For indoor cultivation, even when grown hydroponically, the cultivator can still use compost teas and other natural amendments without necessarily using inorganic nutrient salts. The indoor grower can also use nutrient-rich, organically amended soil, thus allowing them to produce an organic crop. However, the use of artificial lights in the indoor environment precludes the word “natural” in my opinion.

Greenhouse Cannabis Growing: A Hybrid Approach

A third approach to growing is a hybrid cultivation method known as the greenhouse approach. I tend to think of greenhouses as sun-grown; however, a greenhouse can utilize a mixed-light approach. It can also have light deprivation capabilities, meaning the grower can force plants to flower multiple times a year by controlling the light cycle. As this makes it possible to have multiple harvests per year without the huge carbon footprint created by indoor grows, it’s pretty clear that greenhouses are a great hybrid of the two, melding all the benefits with just a few of the drawbacks of both types of growing.

This makes it the most likely approach for the future of high-end cannabis. Indoor greenhouses allow CO2 to be enriched for better flower density, the differential in temperature between night and day to be controlled, and the humidity to be regulated as needed.

All these factors contribute to creating larger terpene glands with more medicine and terpenes. Many greenhouses will have supplemental lighting and need to use some electricity, but far less than indoor grows. Most greenhouses are not sealed, but some can be with different cooling techniques using ambient air. In any case, a greenhouse’s carbon footprint will always be more efficient than a full indoor grow and will give the cultivator the benefits of being able to curate the environment to get the desired results from the flower, while still harnessing the power of the sun. 

The Future of Sustainability in Cannabis Cultivation

I believe the future of sustainable cannabis cultivation lies in a mix of outdoor fields and greenhouses. These approaches to cannabis cultivation allow us to be a more sustainable industry, both in terms of our carbon footprint and in terms of our long-term appeal to consumers, who are increasingly demanding that companies across industries demonstrate a commitment to sustainable practices. Recent studies by Harvard Business show that products with on-package sustainability claims increased by almost 30 percent from 2013 to 2019.  I suspect these numbers are only going to grow as we face ever more dire reports about the state of our planet.

Frankly, it seems weird that we even have to discuss the need to prioritize sustainability in the cannabis industry. So many advocates who pushed for cannabis legalization for decades were part of a larger, greener movement and were sensitive to climate change and nurturing Mother Earth. I think all of us in the cannabis industry owe it to ourselves and to our communities to be greener and look for greener pastures.

As we assess the future of sustainability in cannabis cultivation, the balance between eco-friendly practices and cultivation efficiency becomes key. It’s important to understand and discern the practices that were necessary to survive prohibition from those we can choose today, simply because they are the best, most sustainable ways forward. Let’s do better, now that we can, with our freshly minted, ever-growing abundance and agency with this magical plant.

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