You may have heard of trichomes before if you’ve ever taken a cannabis grow tour or have an interest in the cannabis industry. Trichome is Greek for ‘growth of hair’; they are tiny outgrowths on a plant extending from the epidermal layer.[1] For the cannabis plant, these are the tiny hairs you see on the bud of the cannabis plant, oftentimes characterized by a crystalline appearance. The trichomes house many of the psychoactive compounds known as cannabinoids such as THC and CBD. They also contain terpenes, the compounds we touched on in an earlier blog post, which give different strains of cannabis their unique smells and flavor, as well as amplifying the effects of the cannabinoids.

There are three types of trichomes on the cannabis plant:

1. Bulbous. These trichomes appear on the surface of the entire cannabis plant, but are usually too small to see with the naked eye. Human hair is anywhere from 40-50 microns (micrometers), while bulbous trichomes range from just 10-15 microns. 
2. Capitate Sessile. These are slightly larger trichomes which start to take on the familiar head-and-stalk shape.
3. Capitate-Stalked. These are the most common trichomes and the ones you can examine yourself with the naked eye on your next trip to the dispensary. These trichomes are composed of a basal cell (stalk) with a waxy gland head on top.[2]

The Functions of Trichomes

Trichomes are essential for the cannabis plant, for many reasons ranging from physical defense to medicinal properties. From a biological standpoint, trichomes are essential as a first line of defense for the cannabis plant. The hairy, waxy, sticky trichomes make it difficult for herbivores or insects to eat or destroy the plant itself, as well as make it difficult for mold or fungus to grow on the plant. They also act as a shield of sorts by protecting the plant from ultraviolet radiation, high winds, and low humidity. 

The trichomes are also the factory for all of the psychoactive properties of cannabis. Originally, researchers thought that THC, CBD, and other cannabinoids were produced in the green plant tissue of the cannabis plant, otherwise known as the calyxes. Now, it is widely accepted that the trichomes themselves are responsible for the production of cannabinoids and terpenes.[2]

Life Cycle of Trichomes

The life cycle of trichomes on the cannabis plant are extremely important in the cultivation and harvesting process. The theory is that photosynthetic cannabinoid precursors are transported and converted into mature cannabinoids such as THC and CBD in the secretory vesicles of the gland heads of trichomes.[3] As these cannabinoids and terpenes accumulate in the trichomes, they have a noticeable change in appearance, changing from clear and translucent to amber and opaque when they are nearing maturation. Eventually, this head will get heavy and fall off as the budding process completes.

The difference between amber and translucent trichomes can be seen here.

Expert cannabis growers know that harvesting is all about timing. And this physical change in trichomes is indispensable help for this process. For one, you DON’T want the trichomes to fall off, that’s where all the medicinal and recreational effects are stored! However, there is a sweet spot where veteran growers will be able to harvest the cannabis at its maximum potency. As a rule of thumb, this is when about half of the trichomes have turned into the amber and opaque stage of maturation.

While time is a very important part of the harvesting process, nurturing the trichomes is also a huge part of the process. Without the proper care throughout the maturation process, you may end up with trichomes that lack potency or the proper flavor profiles. Perhaps the single most important factor for trichome development is UV light. The cannabis plant responds differently to certain spectrums of light and bands of wavelengths. These bands of light signal the cannabis plant in important ways, such as when to start flowering. This same UV light is essential in making sure the trichomes produce certain terpenes and cannabinoids in the right quantity.[4] In fact, manipulation of exposure to these bands of light in indoor grows is essentially mimicking the light exposure a cannabis plant would receive outside throughout the maturation process. This is why the proper lighting is one of the most important foundations of any good growing operation.

Another factor to keep in mind is the degradation of the terpenes, which are very closely tied to the trichomes. It’s one thing to get the most terpenes out of a strain, it’s another process to keep these intact throughout the harvesting process so that they reach the final consumer with maximum potency. The best defense we’ve found at Seed & Smith is proper drying and storage procedures. Ensuring a balanced humidity and moisture profile can maintain higher levels of terpenes while lowering the flower’s chances of forming microbial growth. In commercial cannabis, we have found that too slow of a drying process increases the chances for the product to fail total yeast and mold tests. Traditionally, growers have opted for an extended dry period to improve quality; however, they are not forced to go through stringent testing like their licensed counterparts. It’s all about finding the sweet spot!

Concentrates

Concentrates are becoming increasingly popular as a way to consume cannabis, as they can provide extraordinarily clean flavor profiles, high THC content, and are generally a more pure form of cannabis. Concentrates are extracted from the cannabis plant in many different ways. As you can imagine, being saturated with THC, CBD, other cannabinoids and terpenes, trichomes are the building blocks of concentrates. All the quality budder, shatter, live resin and other concentrates are predicated on the health and potency of the trichomes on the cannabis plant. 

The easiest way to identify this is with kief, the fine golden powder you may see at the bottom of your grinder. Kief is basically an accumulation of the separated trichomes from the rest of the cannabis plant matter that doesn’t take any processing or chemicals to produce. 

One interesting byproduct of the harvesting timeline of the cannabis flower is the translation into the color of concentrates they produce. If a plant is harvested when most of its trichomes are still in the translucent phase, the color of the resulting concentrate will skew to the lighter side. Conversely, if most of the trichomes are in the amber stage of maturation, the concentrate will tend to carry that color over to its final stage, making it a more amber or dark color. There are many other factors involved in the production of concentrates that affect the final color such as the extraction and purging process, but the color of the trichomes themselves play an important role. We won’t get too much into the extraction processes or the nitty gritty details on how trichomes are converted into your favorite concentrate in this article. For more information on cannabis extraction processes, visit the Seed & Smith blog.

Trichomes are an essential part of the cannabis plant, and many would even argue they are the most important. Careful planning, cultivation, harvesting, and storage is vital in optimizing the terpenes found in cannabis, and ensuring that the final product is of the highest quality. 

Sources:

[1] Microscope Master – Trichomes: Development, Types, Functions and Microscopy
[2] Honest Marijuana Co. – Trichomes: The Complete Guide
[3] Royal Queen Seeds – Cannabis Trichomes Importance
[4] Royal Queen Seeds – Cannabis Cultivation: The Light Spectrum and Ways to Raise THC Levels