The 0.3% Divide

In the last blog, we untangled the mystery about the taxonomic classification of the cannabis plant.

The next confusion was another classification conundrum—the difference between marijuana and hemp.

In the previous blog, we learnt that cannabis has been cultivated for over 12,000 years, making it one of the oldest domesticated plants in human history. Over time, it diverged into two primary usage types - i.e. fiber-type hemp, valued for its fiber and seeds, and drug-type cannabis, cultivated for its cannabinoid-rich female flowers. I knew that both hemp and cannabis came from the same species, Cannabis sativa, yet I still found myself confused by how differently people spoke about them. Everywhere I looked, they seemed to be treated as two entirely separate plants and that contradiction made me want to dig deeper to understand where this divide really comes from.

So what is the difference between the two?

While they both come from the same species (like we clarified in the previous blog) ie. Cannabis sativa. I understood that this distinction isn’t particularly rooted in nature at all, but in how humans have chosen to use and define the plant. The cannabis plant contains over 500 chemical compounds, including about 125 cannabinoids. The main cannabinoids are delta-9-tetrahydrocannabinol (THC), the primary psychoactive compound, and cannabidiol (CBD), which is non-psychoactive and has medicinal properties. Both play complementary roles in medical cannabis formulations and exhibit distinct mechanisms in the endo-cannabinoid system The primary distinction lies in the plant’s composition and purpose.

The word  “hemp”has deep linguistic roots, tracing back to the Old English hænep and the Proto-Germanic hanapiz, terms that likely originated from ancient Scythian or Thracian languages (Etymology Online). Over time, it came to describe the fiber-producing form ofCannabis sativa a plant cultivated for practical, not psychoactive, purposes. As Collins Dictionary notes, hemp refers to the fibrous variety of the cannabis plant used to make rope, textiles, and other materials.

Historical evidence shows that ancient communities across Europe and Central Asia grew hemp for its strong bast fibers, which were woven into ropes, nets, sailcloth, and coarse fabrics, while its oil-rich seeds were used for food, lamp fuel, and paints.

(Clarke & Merlin, 2013; Britannica, “Hemp”)

But There are others hemps too!!

Hemp nettle (Galeopsis tetrahit)

Sunn hemp (Crotalaria juncea)

Interestingly, several unrelated plants such as sunn hemp (Crotalaria juncea) and hemp nettle (Galeopsis tetrahit) later adopted the name “hemp” simply because their fibers resembled those of Cannabis sativa, even though they belong to entirely different botanical families (Collins Dictionary; USDA Plant Guide). Hemp nettle (Galeopsis tetrahit) Sunn hemp (Crotalaria juncea) Hemp typically includes both male and female plants, with flowers containing less than 0.3% THC. These plants are generally taller and have thicker, more fibrous stalks, making them ideal for producing textiles, rope, and even durable materials like hempcrete, a strong, eco-friendly form of concrete. In contrast, marijuana is usually cultivated from female plants bred to produce higher concentrations of THC, often exceeding 0.3% and reaching up to 30%, which gives the plant its psychoactive properties.

Pawansingh. (2024, February 20). Hemp fibres.

Non Conventional Fibres Association (https://ncfa.co.in/hemp-fibres/) Where does this 0.3% THC limit come from? This  widely recognized 0.3% THC limit originated from a 1976 study by Canadian scientists Dr. Ernest Small and Arthur Cronquist. In their paper titled A Practical and Natural Taxonomy for Cannabis, they sought to create a distinction between industrial hemp and drug-type cannabis used for medicinal or recreational purposes. Dr. Small noted that hemp plants generally contained less THC than marijuana and, to establish a practical boundary, proposed 0.3% THC as the cutoff point. 

(Finley et al., 2022)

(Hemp Vs Marijuana: Key Differences to Keep in Mind for Your Hemp Lab, n.d.)

Interestingly, as discussed in a recent LinkedIn article by Robson Ribeiro, the 0.3% THC limit was never rooted in solid biological science. Dr. Ernest Small himself had called the number “rather arbitrary,” meant only as a taxonomic convenience rather than a biologically meaningful cutoff. The article points out that this outdated standard has real-world consequences. It is difficult for farmers to maintain THC levels below 0.3% as factors like soil composition, Genetics, and weather also impact the THC levels and crops exceeding this are deemed non-compliant and must be destroyed, resulting in significant financial losses for farmers (https://www.linkedin.com/pulse/03-thc-limit-hemp-flawed-standard-its-origins-robson-ribeiro-e39mf/).

Changes happening in the Global Industry

It also limits innovation, restricting breeders from developing cannabinoid-rich but non-psychoactive strains. With countries like Switzerland and Australia now adopting a more flexible 1% THC limit, the 0.3% rule appears increasingly out of touch with both modern science and the realities of cultivation. In the end, the divide between hemp and marijuana isn’t biological.  It’s a product of policy and perception. The 0.3% rule, though arbitrary, has come to shape how we define and regulate the same plant, Cannabis sativa. Beneath those legal lines and cultural biases, it remains one species, molded by centuries of human use and misunderstanding.

About the Author and this Blog Series

Hi, I’m Sanjana, a researcher with a master’s in environmental science. My research sits at the intersection of environment, agriculture, and culture. During my master's, I studied cannabis in the Parvati Valley, exploring local knowledge, traditional practices, and global policy debates.

That is when I realised that cannabis is not just a plant but a story full of history and controversy.  Many from the valley chose not to speak about it, many have forgotten about the traditional use, and many are just milking it for the sake of money. But overall, nobody wants to talk about it. Few wanted to talk about it, fewer wanted to be seen with it, and almost no one wanted to touch it. This silence and stigma around cannabis is what inspired the title of this series - "The Untouchable Plant."