In the rapidly evolving landscape of agriculture and healthcare, medicinal cannabis stands at the intersection of innovation and opportunity. As global demand for natural, plant-based remedies grows, the medicinal cannabis industry offers a unique chance for cultivators to enter a high-growth market with significant potential.
With the country’s ideal climate, extensive arable land, and established agricultural expertise, Mzansi is well-positioned to become a key player in the global cannabis market.
Alec Yardley, a horticulturalist, sheds light on the intricacies of cultivating medicinal cannabis, including essential management practices and the complex legal landscape that governs this emerging industry.
Medicinal cannabis is grown specifically to harness its therapeutic compounds, primarily THC (tetrahydrocannabinol) and CBD (cannabidiol). These compounds are widely recognised for their ability to alleviate pain, manage chronic illnesses, and address various other health conditions.
Legal compliance and quality control
Yardley emphasises the importance of compliance with South African regulations and international standards in the cultivation of medicinal cannabis. This involves obtaining the necessary licences and approvals from relevant authorities.
“When I talk about legal, I’m talking about licensing. In order to cultivate medicinal cannabis, you need a licence. That licence is regulated by SAHPRA or the South African Health Products Regulatory Authority. It’s quite a stringent application because at the end of the day, you are growing medicine,” he says.
Yardley notes that because medicinal cannabis is a high-value crop, implementing comprehensive security measures is crucial. This includes securing the facility and ensuring that only authorised personnel can access sensitive areas.
In addition to this, he highlights the necessity of adhering to good agricultural and collection practices (GACP) and good manufacturing practices (GMP) to maintain the efficacy and safety of medicinal products.
“To export your product, the cannabis, you still need to comply with the SAHPRA regulations as well as your international trade laws. On top of that, as with any other agricultural operation, you need to adhere to your GACP or good agricultural and collection practices and your good manufacturing practices. One last thing is [having] very detailed records of cultivation practices, inputs used, and plant tracking for traceability,” he says
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Top 3 mediums for cannabis cultivation
Living soil: Yardley explains that living soil is gaining popularity as it involves enriching the soil with organic amendments. This approach allows the soil to retain nutrients and microbial content effectively.
“Once that’s set up, it really requires minimal input. That’s one of the quite popular mediums.”
Hydroponics: This medium offers precise control over various factors such as nutrient delivery, water, pH levels, and electrical conductivity (EC), Yardley says.
“Funny enough, it has good water efficiency. You think obviously growing with hydroponics is a lot of water and you’re wasting water, but if you’re using the right system, like a closed loop system, you’re recirculating water. It is quite efficient.”
Yardley notes that hydroponic systems are complex and come with high costs that need to be considered when choosing this medium.
Coco peat/Coir: Yardley describes coir as a widely used medium in various agricultural operations, including tomatoes and cucumbers. It is known for its versatility and effectiveness as a growing medium.
“It is also quite a sterile medium and very good for water retention.”
Growth stages
According to Yardley, cannabis typically takes about six months to grow from seed to maturity in its natural environment. He further explains that by growing the plant in a controlled environment, the growth cycle is shortened to approximately three months.
“What we’re doing is we’re putting it into a controlled environment and we’re reducing that to half the time. [It] takes roughly three months to complete the plant cycle,” he says.
The growth stages are as follows:
- Clonal/seedling phase: Initial phase of 1 to 2 weeks.
- Vegetative stage: Lasts approximately 3 to 4 weeks.
- Flowering stage: Longest phase, lasting about 8 weeks.
“At the end of that, you should be sitting with a nice big plant,” Yardley says.
Understanding photoperiod sensitivity
Yardley says cannabis is a photoperiod-sensitive plant, meaning it senses changes in light to regulate its growth stages. In nature, as seasons change from summer to autumn and winter, the plant senses the shift in light and transitions into its flowering phase.
“What we basically do is in the vegetative stage, we give the plants roughly between 16 to 18 hours of straight light with about six hours of darkness. That keeps the plant in a vegetative state, and it continues focusing on growing branches, branching out, and building a good structure.”
To induce flowering, Yardley explains, the light is reduced to 12 hours of light and 12 hours of darkness, signalling the plant to focus on developing flowers, which are the desired product. This phase is the longest and most critical, as it allows the development of high-quality flowers.
“South Africa is very ideal. It is one of few places around the world that offers some of the best conditions in the world. I think that’s why the market is growing and it is developing because people are seeing the possibilities. The light is not an issue at all. We’ve got really great summers.”
Yardley adds that the range of biomes allows for optimal growth conditions, as different cultivars require specific temperatures and environmental conditions.
THC and CBD content
Strain selection is driven by market demands. Yardley explains that the objective is to develop strains with high THC, CBD and terpene content.
“The main focus is to really develop a well rounded cannabinoid profile that matches the needs of the consumer. We combine this with its ability to grow in our sort of setup, for example, some crops tend to be high yielding, but are unfortunately prone to certain diseases, this is where your selection criteria come into play.”
Controlling pests and diseases
Yardley says aphids, thrips, and fungus gnats are some of the most common pests encountered in cannabis cultivation. Some common diseases in addition to this are powdery mildew, botrytis, root rot, and stem rot. He explains that a well-implemented integrated pest management (IPM) programme, including regular plant inspections and monitoring, is crucial to keeping pests and diseases under control.
How to know the plant is ready for harvest
Harvesting cannabis is all about timing, Yardley emphasises. The right moment to harvest is crucial to ensure the best quality and potency of the final product.
“You’ll start to notice that the leaves start to turn yellow because all the nutrients and energy are focused on the bud development and ripening. Eventually, it gets to a point where the plant is going into senescence, which is death basically, but for plants.”
A tool used for closely inspecting small details, a jeweller’s loupe, is often used to examine the trichomes on the bud. “Those trichomes often start out as a clear, glassy colour, but towards the end of the plant’s life cycle, they turn to more of a milky white or amber colour. That’s when you know that your plant is ready to harvest,” Yardley says.
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Updated: 4 September 2024
