Hemp and marijuana are the same species of plant — Cannabis sativa.
The difference is in their specific growth habits.
Hemp is any strain of Cannabis sativa that contains less than 0.3% THC (the main psychoactive compound in the plant). These strains are used for making textiles, biodiesel, and nutritional supplements such as CBD.
Marijuana is any cannabis strain with more than 0.3% THC by dried weight. Marijuana can include both Cannabis sativa and a related species — Cannabis indica. These strains are used primarily for their psychoactive effects.
Introduction to the Cannabis Family
All cannabis plants, including hemp and marijuana, are members of the Cannabacea family. The only other notable member in this family is the hop plant (Humulus lupulus) — one of the primary ingredients in beer brewing.
Within the Cannabacea family, there are three main cannabis species to be aware of — each with their own unique growth characteristics.
A) Cannabis Sativa
Cannabis sativa is the most widespread species of cannabis. There are hundreds of different strains of this species, some with high THC content (marijuana), others with very low THC content (hemp).
This species is believed to have originated from Southeast Asia, where the humidity is much higher and the growing season is longer. As a result, it has the longest flowering time of all the cannabis species and grows the largest.
B) Cannabis Indica
Cannabis indica originated from northern climates and, therefore, has a higher tolerance for cold weather and a much shorter flowering time to accommodate the shorter growing seasons.
It’s only recently become a popular species for growers looking to produce psychoactive crops thanks to its smaller plant size and larger flower size. This is ideal for people cultivating the plants indoors under lights. A large Cannabis sativa strain would normally grow too tall to be successfully cultivated indoors without special consideration regarding the design of the growing space.
There are no Cannabis indica strains currently classified as hemp. All members of this species are classified as marijuana.
C) Cannabis Ruderalis
Cannabis ruderalis is the lesser-known cannabis species. It’s a small plant that produces very low yields and lacks any notable fiber content.
What makes this strain unique is its ability to produce flowers irrelevant of the day length. This compares with Cannabis indica and Cannabis sativa, which are both highly influenced by day length (the days growing shorter triggers them to begin flowering).
Why Does Hemp Exist?
Cannabis is best known for its psychoactive effects through the THC content of the resin produced by the flowers. However, THC and the plants that produce it are illegal throughout most of the world. It’s been this way for the last 80 years.
The cannabis plant has a lot of other useful traits to offer outside of its psychoactive effects. The fibrous stems are valuable for manufacturing textiles and biodiesel, the seeds make for a rich source of nutritional protein and fatty acids, and the leaves are rich in medicinal compounds such as cannabidiol (CBD) and cannabichromene (CBC).
It was discovered shortly after the banning of THC and the plants that produce it that some species of cannabis didn’t have any psychoactive effects. These plants were later classified as “hemp” — noting that to be considered hemp, the plant had to produce less than 0.3% THC by dried weight.
Now, hemp is completely legal throughout the United States as well as most of the world. Any supplement made from hemp is considered a nutritional supplement rather than a psychoactive drug. Marijuana, in comparison, is considered a recreational drug, and its cultivation is highly restricted.
Most of the CBD supplements on the market are, therefore, manufactured from hemp in order to fit into this classification.
1. Growth Habits: Hemp vs. Marijuana
Hemp and marijuana can have similar growth habits. Both hemp and marijuana strains of Cannabis sativa tend to be very tall with thin leaves. Other forms of marijuana that come from Cannabis indica tend to be much shorter and bushier and have thicker leaves.
The main difference in growth habits between hemp and marijuana are specific to the resin produced by female flower buds. The resin on marijuana strains tends to be much thicker and stickier than hemp. This resin is where the majority of the CBD, THC, and other cannabinoids are produced.
Hemp, on the other hand, produces far less resin and will tend to accumulate the valuable cannabinoids within its dark, rich leaves.
2. Chemical Composition: Hemp vs. Marijuana
The chemical composition of hemp and marijuana is the main differentiator between the two plants.
As mentioned, hemp strains are only classified as such if they produce less than 0.3% THC by dried weight. Anything over this concentration is considered marijuana.
The other cannabinoids in the plant (there are over 80) can vary substantially.
Some hemp is high in other cannabinoids such as CBC or CBG, while others contain almost exclusively CBD.