Why Is Weed So Smelly?

From flowers that smell like a rotting corpse up to a mile away in Indonesia to trees that smell like a certain bodily fluid growing all over North America, Mother Nature fills the air with all sorts of odors come spring time.

Cannabis doesn’t hold the record for world’s smelliest plant, but it sure can seem like it sometimes. Terpenes alone can’t explain the smell; cannabis actually has a specific part of its anatomy dedicated to making it smelly.

Volatile compounds called terpenoids constantly vaporize off the plant, fresh or dried, and each different strain has its own unique terpene profile and its own characteristic smell.

Terpenoid compounds are also responsible for the smells in many other plants, like pine or lemon trees, and cannabis actually has many terpenoids in common with other plants.

Of course, these volatile terpenes cause the plant smell in the first place, but plenty of other plants and fruits have far greater amounts of terpenes  and don’t smell nearly as strong. It turns out a special part of the anatomy of the trichomes of cannabis help volatilize terpenes into the atmosphere, making it as smelly as it is.

According to the extensive work on trichome anatomy done by Kim and Mahlberg, they hypothesized that little striae help volatilize terpenoid compounds into the atmosphere. Forming a network of microscopic channels, these striae connect the secretory vesicles (and the secretory cavity at large) to the outside of the cuticle. Terpenoid compounds are created in the secretory vesicles within the trichome; if they didn’t have a way to get out through these striae, the plant wouldn’t smell nearly as much as it does.

This image generated using a transmission electron microscope from Kim and Mahlberg’s 1995 report shows the cuticle of a trichome, its outermost layer. Pointed out in black arrowheads you can see the striae near the top (the gray area that represents the outer cuticle) with some near the middle as well.