There are three ways to cultivate cannabis commercially: hydroponically, organically, or a hybrid of the two.
Hydroponics is the practice of growing plants without soil. Instead, growers provide plants with an oxygenated, nutrient-rich solution delivered directly to their roots. The energy the plant would dedicate to root growth in search of food and water in a traditional soil environment can instead be redirected to development on the top part of the plant—resulting in faster growth and larger yields. Hydroponics also allows the grower to have total control over nutrient management since the fertilizer solution is mixed from water-soluble mineral salts. Growers can control to the part per million exactly how much of each nutrient the plant receives.
Hydroponics usually incorporate the use of a substrate. This sterile medium acts as a sponge to retain water and nutrients and slowly releases them back to the plant when required. Traditional hydroponic substrates are rock wool, peat moss, vermiculite, perlite, and expanded clay pellets. These are sometimes mixed together, or they may be used as a standalone substrate. Increasingly, other materials are being used such as rice hulls, wood chips, and coconut shell fiber. They are waste products that can be available cost-effectively in great abundance, depending on your location.
The most advanced methods of hydroponics use no substrate at all. In Deep Water Culture (DWC) and Nutrient Film Technique (NFT) systems, the plants sit directly in an oxygenated nutrient solution that covers the roots 24 hours a day. In aeroponics, plants are suspended in the air and their roots are sprayed with a fine mist of nutrient solution. Growers that master these methods can realize unprecedented results in terms of faster crop cycles and increased yields, and they eliminate the risks of soil-borne pathogens since there is no soil.
However, cultivating hydroponically without a substrate is the riskiest way to grow. Cultivators must maintain precise temperature and oxygen levels in the nutrient solution at all times, or the roots can begin to rot. The nutrient solution in these systems is typically recirculated, so if one plant becomes sick, the disease will spread to the rest of the crop. Also, this method of growing leaves little room for error. These systems involve hundreds of valves, pumps, and tubes, and any malfunction in the network can leave a plant’s root system exposed to dry air and heat. In this scenario, if the sun is shining or the grow lights are on, it’s possible to lose a crop in a matter of hours.
Organic cultivation involves the use of soil and plant or manure-based composts. Organic soils are rich with living microbes that slowly breakdown components in the soil and release nutrients to the plant. Although scientific evidence is lacking, there is anecdotal evidence that organically grown cannabis exhibits a richer terpene profile than its hydroponically grown counterparts, meaning that organic cannabis smells and tastes better. For this reason, organically grown cannabis flower can command higher prices at retail.
Launching an organic commercial cultivation business can be tricky. First, the raw ingredients for the soil and compost need to be sourced consistently. The key to successfully scaling a cultivation business is repeatedly doing the same thing and doing it on a large scale. If the sources of your compost and soil supplies vary seasonally or potentially could run out, it will be difficult to establish consistency in your operation. Nutrient management can also be difficult since the grower can’t measure out 100 ppm of nitrogen, mix it with water, and then apply it to their plants. Instead, they make compost or brew a compost “tea” and apply it to the soil. This method makes it more challenging to determine how much of a nutrient will be available to a crop and when.
Organically grown plants develop slower than hydroponically grown plants, tend to yield less, and are more labor-intensive. Currently, there is no national organic certification process for cannabis growers. Although this will likely change soon, at the moment, anyone can claim that their cannabis is grown organically. Growers looking to export to medical cannabis markets overseas should ask themselves if it will be feasible to label their product as organic. When was the last time you purchased medicine in a pharmacy that was labeled organic? If this won’t be possible, be prepared to accept lower yields, slower growth, and a higher production cost that you will likely not be able to recoup on the day of sale.
A hybrid cultivation approach is common in large outdoor and greenhouse facilities where the goal is mass production at a low cost. Plants are grown in soil beds amended with organic materials, but they are fed with water-soluble hydroponic nutrients. This way, the plants benefit from the health of the soil, and the grower can also better control the nutrient requirements of the plant. The most significant disadvantage to hybrid cultivation is the risk of soil-borne pathogens in the growing beds. Damaging insects can be challenging to control, and mold spores can hide and remain dormant in the soil for months. There are chemical approaches to fumigating a soil bed, but they are generally prohibited in the production of medicinal cannabis.
So, what’s a grower to do? Here are recommendations for three different cultivation scenarios based on the grower’s end product:
Cultivate using both greenhouse and open field production. With oil extraction, the customer does not see the flower, so imperfections in the crop are irrelevant. Amend the soil organically but take the hybrid approach and fertilize with water-soluble mineral fertilizers. Outdoor cultivation may be seasonal, but it is also a very inexpensive way to cultivate. One good harvest will yield a lot of biomass for oil extraction.
To hedge your risk, also grow hydroponically in a greenhouse using a common substrate, like rock wool or coconut shell fiber. Greenhouse production allows for more control, as well as perpetual harvests throughout the year.
Scenario 2: Cannabis flower sales to dispensaries
Cultivate hydroponically in a high-tech greenhouse. This route is more expensive than building a basic greenhouse, but it’s less costly than building and operating an indoor site. Grow in a hydroponic substrate like rock wool, coconut shell fiber, or a peat-based mix.
Grow indoors using 100% hydroponics. Avoid deep water culture or aeroponics as a start-up cultivation strategy since they are risky, allow little room for human error, and the long learning curve will likely delay your entry to market. Most cannabis grown for export requires certification of Good Agricultural and Collection Practices (GACP) and Good Manufacturing Practices (GMP), so incorporate these principles from the beginning to avoid expensive retrofits later.
In Case You Missed It
How to Determine the Best Way to Grow: Part One