When you look at cannabis close-up, it’s covered in small, crystalline hairs. When properly cured and trimmed, buds will often sparkle with cloudy or amber-colored trichomes. Those hairs are actually tiny resin glands that produce cannabinoids, flavonoids, and terpenes, the essential oils which give cannabis its medical properties, its smell, and its flavor.
When you consume cannabis, it is the trichomes containing cannabinoids like THC and CBD that provide relief and relaxation. If you use a grinder to break apart your cannabis flower, it may contain a screen that catches the remaining crystals, called kief, which you can save and consume. Cannabis oil is made from the essential oils that trichomes contain and is extracted from plant matter to form a concentrate.
Types of Trichomes
The visible hairs on the cannabis plant are “capitate-stalked trichomes”, which are about 50-100 micrometers long. Capitate-stalked trichomes are most densely concentrated on the cannabis flower, where they secrete cannabinoids like THC and and CBD.
Even cannabis leaves and stalks are covered in microscopic trichomes that produce cannabinoids and terpenes in smaller amounts. Smaller protrusions of plant cell clusters called bulbous trichomes, are invisible to the naked eye. Capitate sessile trichomes consisting of a stalk and a head also cover the plant. These trichomes can be viewed with the aid of a microscopic lens.
Growers will often use a hand-held microscope under LED light to examine the cannabis trichomes and determine when the plant is mature enough to harvest. The genetic type of cannabis strain and environmental factors such as soil conditions and light exposure determine the rate at which trichomes are produced, and will be different for each harvest.
Why do trichomes exist?
The word “trichome” comes from the ancient Greek, “trichōma” or hair. The botanical definition of trichome is “fine outgrowths or appendages on plants, algae, lichens, and certain protists.”
These small hairs are found on a variety of plants, from stinging nettles to bean leaves. In the wild, the primary function of trichomes is to protect plants and other flora from insects and animals. Trichomes ward off predators by emitting unpleasant smells to ward off pests or providing a prickly, unpleasant tasting experience for herbivores that might otherwise devour a plant. Trichomes also protect plants from the sun by covering the surface of leaves and reducing the heat that plants absorb from sunrays.
How it works
Capitate-stalked trichomes (the ones you can see without a microscope) contain a head and a stalk. The stalk emerges from the surface of the plant, and cells within the stalk transport nutrients to the bulb on top, also known as the gland head.
The base of the head contains cells take the nutrients, metabolize them, and secrete oils that are converted into cannabinoids and terpinoids. These oils, also known as resin, accumulate on the outermost layer of the gland head, producing the fine, crystalline hairs that you see.