If you become a medical cannabis patient and your doctor prescribes you dried flower, it’s likely that your prescription will come with both a product name and the name of the cannabis strain the product comes from.
Cannabis strains (technically known as "cultivars") often have evocative names like Wedding Cake, Green Gelato and Peanut Butter MAC, which may sound delicious, but don’t tell you much about what makes the strains different from one another. And while the names of marijuana strains often suggest different effects, smells and flavours, from a therapeutic perspective it’s more important to pay attention to the cannabinoid and terpene content.
As a patient, it’s helpful to learn where cultivars come from and why they’re so pervasive in cannabis culture, as well as their relevance from a medical perspective.
What Is a Cannabis Strain?
All medical cannabis (and recreational cannabis) comes from the Cannabis sativa plant. This flowering plant with broad leaves has been cultivated for thousands of years, with medical usage being recorded as far back as 2800 BC.
Cannabis is a complex plant that contains hundreds of active compounds, including cannabinoids such as THC and CBD, flavinoids and terpenes. As they spread around the world, cannabis plants evolved into several distinct strains called “landraces,” which were adapted to the environment where they grew. For example, plants that grew in the high-altitude mountains of Afghanistan were very different from those that evolved in the heat of the Mexican sun.
How Did Modern Cannabis Strains Evolve?
Over the last century – and especially over the past few decades – cannabis enthusiasts began experimenting by breeding these distinct landraces to create new strains. They discovered that each strain presented with a unique smell, flavour and appearance, not to mention different psychoactive effects.
During the 1960s, cannabis breeders in California introduced strains from the Himalayas, which grew better in the California climate than strains from Central America. As they experimented, they created new weed strains, many of which are now legendary, such as Skunk, Northern Lights and Haze.
Since then, breeders have continued to create new strains by breeding new and old together. Each year, slight variations accumulate and eventually create new strains. A 2015 study suggested there were more than 700 cannabis strains currently being cultivated, while a user-generated database like Leafly documents more than 6,500.
What’s The Difference Between Marijuana Strains?
Marijuana strains have unique genetic profiles that affect many aspects of the plant, including:
Cannabinoid content: each strain has a unique combination of THC, CBD and other cannabinoids, which influences its psychoactive effects.
Terpene content: terpenes are aromatic compounds that affect the flavour and smell of cannabis. Again, each strain contains a distinct mixture of terpenes like limonene, myrcene, and pinene.
Appearance: cannabis plants can look very different. Leaf size and shape, flower colour and the number and distribution of buds all vary.
Flavour and smell: because the terpene content of cannabis strains varies, each strain has a unique smell and taste. Strain flavours are often described as “floral,” “earthy,” “sour” and “citrus,” among many other adjectives.
Different Types of Strains: Indica, Sativa, Hybrid
Cannabis strains have traditionally been split into three broad categories: Indica, Sativa and hybrid. You’ll see these names everywhere and many claim that each type has a distinct effect. Sativas are said to be energising, while Indicas are sedating and hybrids are somewhere in the middle.
However, recent research suggests this distinction isn’t entirely accurate. For example, one study found that “strains labelled Indica were just as closely related to strains labelled Sativa as they were to other strains labelled Indica.”
So, where do these labels come from? Initially, the terms Sativa and Indica were used to describe two types of the cannabis plant that looked different and came from different parts of the world. But these physical differences don’t correlate with specific psychoactive effects.
Over decades of breeding strains together, it seems the distinction between the strains has become increasingly blurry. Now, the best way to understand the effects of a particular strain is to pay attention to the cannabinoid and terpene content.
However, because the terms Indica, Sativa and hybrid are still widely used, let’s explore how cannabis culture still uses them and what they’re intended to mean.
The original Cannabis indica plants evolved in the mountains of the Hindu Kush, a relatively cool area in central Asia. They were described as short, dense plants with tightly packed branches and leaves. Indica plants have broad, flat fan leaves and a darker green colour.
Indica marijuana strains are often described as relaxing or even sedating. Some people choose Indicas to relieve pain and anxiety or help treat insomnia. You might hear the effects of Indica strains described as a “body high” or feeling “stoned”.
Some of the most famous Indica strains include Northern Lights — one of the original Californian Indicas bred in the 1960s — Grandaddy Purple, Hindu Kush and Girl Scout Cookies.
Sativa plants are better adapted to hot, dry climates like Africa, Central America and Southeast Asia. Compared to Indicas, they’re taller, with sparse branches and long, thin leaflets. They also tend to have a lighter green colour.
In contrast to the calming effects of Indicas, Sativas are said to be energising, causing a “head high” that can include euphoria, creativity and productivity. Some say Sativas can make you feel more sociable and “high” rather than stoned.
Pineapple Express, Gorilla Glue, Sour Diesel and Lemon Haze are some of the best-known Sativa strains. While both Indicas and Sativas have high THC content, many Sativas have lower CBD content.
In reality, all modern marijuana strains are hybrids. But the term hybrid is used to describe a group of cannabis strains with balanced effects, somewhere between Sativas and Indicas.
Hybrids are sometimes described as Sativa-dominant, Indica-dominant or 50/50 hybrids. The exact effects will depend on which strains the hybrid was bred from. Some will make you sleepy, while others could fill you with energy. Popular hybrid strains include Gelato, Chemdawg, Skywalker and Runtz.
What About Pure THC & CBD Strains?
While pure THC and CBD medical cannabis products are popular for their predictable effects, you can’t get a pure THC or CBD marijuana strain. Every cannabis strain contains a diverse mix of cannabinoids and terpenes. While it is true that certain strains are predominantly CBD or THC, there are still dozens of other cannabinoids present, just in much lower amounts.
Pure THC or CBD products are made by extracting cannabinoids from raw plant material and then distilling that extraction down even further. The purest products are called isolates and contain upwards of 99% pure THC or CBD.
Common Strains of Cannabis
As mentioned, there are potentially thousands of distinct cannabis strains currently being cultivated, yet there are a handful that are over-represented among growers.
Afghani is an Indica strain that’s known for its deeply relaxing and sedating effects. One of the original landrace strains, Afghani has been cultivated for hundreds of years and is the parent strain for many of today’s commonly cultivated crops. Afghani has a potent, earthy smell caused by the terpenes terpinolene, myrcene and pinene and its THC content is moderate.
Girl Scout Cookies
Girl Scout Cookies (GSC) is an award-winning hybrid strain. It was first created in 2010 in California by crossing two other well-known strains: OG Kush and Durban Poison. GSC contains high levels of THC and very little CBD.
A more recent creation is Gelato, another hybrid that has been bred from strains related to GSC. It has a sweet, herbal flavour and a dark purple colour. Like GSC, Gelato contains significant levels of THC with low CBD content, while terpenes such as caryophyllene, limonene and humulene are responsible for its fruity taste.
How To Choose The Right Strain For You
There are now over 300 medical cannabis products available to Australian patients. They’re divided into five categories based on the relative levels of THC and CBD and include oils, dried herb, capsules, lozenges and topical creams.
But unlike in the US and Canada, where cannabis is more readily available, patients in Australia can only access medical cannabis under the advice of a medical professional, who helps navigate the process from start to finish. This could be your local GP, or else there are medical cannabis doctors who can work with patients to find the best solution for their experience and condition before issuing a prescription.