One of the world’s oldest crops, used for thousands of years to make
everything from pants to bricks, also makes potent insect repellants.
But people have learned to use those repellants in religious ceremonies and for entertainment.
This is a plant that depending who you ask can ruin lives, be a beloved panacea,
or simply a helpful invention when there were no better alternatives. This is cannabis sativa.
Hi, I’m Tasha the Amazon and you’re watching Floralogic.
Cannabis Sativa, also known as hemp, is one of th e most used plants in the history of the world.
People have found hundreds of uses for it, but it’s now tightly regulated and in some countries
trading it illegally is punishable by death. So how did we get here?
The earliest evidence of hemp use is from about 10,000 years ago, making one of the oldest known
plants to be cultivated. East Asian peoples were the first to use its fibers to make clothes, rope,
and paper. I’ll teach how they did it in a bit. In the 5th century BC Herodotus wrote that some
central asians liked to burn hemp seeds and “bathe” in the smoke.r
Iron age middle eastern people were known to use it recreationally
and by the middle ages it had reached Europe, where it was used for all those things,
as well as for food. Europeans then introduced it to South America, from where it spread to
North America, becoming then a truly global crop.
Let’s break this up a little bit though. How do you make paper and clothes out of an herb?
First you gotta get rid of the useless parts. The stalk of the plant has an outer layer
called the epidermis, which is kind of the skin of the plant. We don’t need that.
The center of the stalk is the stem. It transports fluids but we don’t use it. Between the stem and
the epidermis there’s the bast fiber, which gives the plant support. That’s where the money is.
After you remove the bast fiber from the rest of the plant
you end up with long threads that can be woven to make textiles four times stronger than cotton.
And if you grind the fiber you can make a slurry, which is then dried into a sheet to make paper.
Pretty easy, right? It just took several days to make a little bit of thread and a couple sheets
of paper. It seems like a huge hassle to us, but back in antiquity this was a game changer.
In more recent times it has also been used as a construction material and even as a biofuel.
And its seeds, which were highly valued in the middle ages, have become a modern nutritious
snack due to their high nutritional value. So, if this plant can be so useful,
what makes it so tightly regulated? Their flowers. They can contain high
concentrations of psychoactive compounds, which basically alter how the nervous system works.
The plant has over a hundred different compounds called cannabinoids.
The one that most strongly affects the brain’s activity is tetrahydrocannabinol,
or THC, attaches to neurons and changes the rate of neurotransmitter production.
This affects the amount of information transmitted in the nervous system,
and creates side effects such as euphoria, relaxation, and in some cases, anxiety.
Most industrial hemp has very low levels of THC, so it doesn’t produce these effects
when consumed. Plants that have high THC levels have been specifically bred for this purpose.
People have been breeding cannabis for its psychoactive effects for at least 5,000
years. The trick was to select plants that produce high levels of chemical defences.
THC is a secondary compound, meaning that the plant doesn’t need it to survive.
There’s a lot of theories on why they’re even there,
but the most accepted one is that it’s excreted by the plant to repel insects.
Some plants defend themselves against insects by making themselves toxic to their predators.
But in certain doses, those same compounds that kill or repel insects can have desirable
effects on people. Nicotine and caffeine are thought to exist for this reason.
Even after thousands of years, there's been a lot of debate regarding the long term effects of THC
usage, so we won’t get into it here. What we do know is that it can be
used medicinally. S trains with low THC are particularly sought after,
especially if they have high concentrations of CBD, a cannabinoid with no psychoactive
effects. Several countries allow medical cannabis to treat anxiety, nausea, chronic,
and a myriad of other ailments. But there’s still ongoing research regarding its effectiveness.
Unlike other plants we talk about on this show, this is most likely illegal to grow in your
country, so please make sure to follow your local laws. Don’t get yourself in trouble over botany!
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