Cannabis trichomes: where the magic happens

You've probably caught yourself at some point gazing at those sticky little droplets that adorn CBD flower, like beautiful dewdrops filled with a magical resin. As you probably know by now, these tiny dots you can see with the naked eye are cannabis trichomes.

In today's post we explain what these curious structures do, how they work, why growers keep a close eye on their change of colour, and plenty of other curiosities. Grab your magnifying glass and join us on this fascinating journey!

The 3 key ideas

• Trichomes are resinous, mushroom-shaped glands that cover the buds; this is where the plant synthesises the cannabinoids (THC, CBD) and the terpenes.
• There are three glandular types – bulbous, sessile capitate and stalked capitate – and only the stalked capitate ones, at 50-100 µm, are visible to the naked eye.
• Their colour marks ripeness: translucent (immature), milky white (optimal harvest point) and amber (more relaxing effect).

What are cannabis trichomes?

Cannabis trichomes are tiny, translucent, crystalline structures found on the surface of cannabis plants. They coat the leaves and buds, as if they were a layer of dew. It is in these structures that the plant produces its aromatic and psychoactive compounds: terpenes and cannabinoids.

The etymological origin or meaning of “trichome” is related to hair. It comes from the Greek word “tríchoma”, which derives from “thrix, trichos”, meaning “hair”. The suffix “oma” is used to refer to a particular structure or formation, in this case to describe the hair-like filamentous structures found on the surface of various plants, including cannabis.

Function of trichomes in plants

Trichomes are specialised structures that plants (of many species, not just cannabis) have developed to protect themselves from harsh environmental conditions and predators. Their functions are therefore directly linked to survival and adaptation to the environment.

Although the whole cannabis plant is covered in trichomes, glandular trichomes are found mostly on the buds or inflorescences of the plant, including the small leaves of the buds or bracts (known as sugar leaves). It is easy to see why during the plant's reproduction, the appearance of trichomes covering the flowers and bracts of cannabis is so impressive: it is a crucial moment in the life of the plant.

In female cannabis flowers, this overpopulation of trichomes is much more abundant than in male cannabis plants, since only the female flowers produce the plant's fruit or seed (in fact, scientists are still studying how this sexual dimorphism comes about).

Hundreds of sticky chemical compounds are synthesised in the trichomes, and with their pointed shapes they make it harder for insects and other herbivores to reach the leaves, stems, flowers or other parts of the plant, preventing possible damage. In this way, trichomes act as “guardians” of female cannabis flowers, protecting them so that they can develop in all their splendour.

In fact, in the cannabis plant, trichomes are true “chemical traps”: they act as a physical barrier, and many cannabinoids and terpenes have shown insecticidal properties. Predators become trapped and weakened, and cannot physically move around the plant. The trichome layer also protects the plant and its tissues against harmful UV rays.

Types of cannabis trichomes

The cannabis plant has two basic classes of trichomes. The first are non-glandular trichomes, which lack the typical spherical head, do not secrete substances and have a hair-like appearance. The second class is glandular trichomes, which attract great interest from enthusiasts of the plant, as this is where phytocannabinoids and terpenes are produced.

There are three types of glandular trichomes on cannabis plants. From smallest to largest, they are: bulbous trichomes, sessile capitate trichomes and stalked capitate trichomes.

Capitate trichomes

The stalked capitate trichomes of cannabis are the largest and have a very distinctive shape, reminiscent of miniature mushrooms. With a diameter of 50-100 micrometres, stalked capitate trichomes are the only ones large enough to be seen with the naked eye.

These trichomes are found mainly on the female flowers and play a crucial role in the production of pharmacologically active compounds in the cannabis plant. They are the plant's most advanced and efficient producers of cannabinoids and terpenes.

Sessile capitate trichomes

Sessile trichomes have a globular head similar to that of stalked trichomes but, as their name suggests, they have no stalk (they are sessile) or only a very short one. In a magnified photo, you can see just the “cap” of the mushroom. This type of trichome is considered to be the precursor stage of immature stalked trichomes.

Bulbous trichomes

Finally, the smallest are the bulbous trichomes. They can measure up to 30 microns across, so they cannot be seen with the naked eye. They are less active than the previous ones and produce a limited amount of cannabinoids.

How are cannabinoids and terpenes synthesised in cannabis trichomes?

More than 110 types of cannabinoids and more than 120 cannabis terpenes have been identified to date. And the most astonishing thing is that all these chemical compounds of cannabis are produced in these tiny structures, the trichomes. Cannabis flavonoids, on the other hand, although also produced in the trichomes, are more abundant in the leaves of the plant.

Inside the trichomes, cannabinoids and terpenes are synthesised in the secretory disc cells (disk cells), which line the base of the trichome's globular head. These cells contain the enzymes responsible for the complex biochemical processes of cannabinoid biosynthesis and terpene biosynthesis.

The secreted substances are stored in a subcuticular cavity, located above the secretory disc cells. This cavity changes from milky white to dark brown as the flowers mature, something growers watch very closely.

Cannabinoid synthesis

In the case of cannabinoids, the main precursor is cannabigerolic acid (CBGA), also known as “the mother of cannabinoids” (or “the father of cannabinoids”, according to others). It is formed via the methylerythritol phosphate (MEP) biosynthetic pathway and olivetolic acid. From CBGA, the trichomes produce various cannabinoids in acid form, such as tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA).

These acids are converted into the more active forms, such as tetrahydrocannabinol (THC) and cannabidiol (CBD), through decarboxylation, which usually happens with heat (as when a joint burns). To a lesser extent, it also happens during the drying and curing of cannabis buds.

Terpene synthesis

Like cannabinoids, terpenes are also synthesised in the secretory disc cells of the trichomes. Their biosynthesis is similar to that of cannabinoids, via the mevalonate and methylerythritol phosphate (MEP) pathways. These pathways produce isoprenoid precursors (such as geranyl pyrophosphate and farnesyl pyrophosphate), which enzymes use to produce different terpenes.

Terpenes are responsible for the characteristic aromas and flavours of cannabis strains and play an important role in the organoleptic and medicinal properties of the plant. There are many types of terpenes in nature, but the cannabis plant mainly contains monoterpenes (myrcene, limonene, alpha- and beta-pinene, linalool, terpinolene) and sesquiterpenes (humulene, beta-caryophyllene, bisabolol).

How trichomes work: much more to discover

Although it may seem that everything has been studied, research into the synthesis of cannabis compounds inside the trichomes is only just beginning. The production of substances such as THC and terpenes in the trichomes of the cannabis plant is influenced by various factors, both genetic and environmental. These include the genetics of the plant, the ripening of the buds, the amount of light the plant receives, and the temperature and humidity of its surroundings. These factors affect the way the plant's genes are expressed (epigenetics) and how the enzymes in the trichomes work.

It has also been found that buds at the top of the plant have higher amounts of cannabinoids and terpenes than flowers lower down on the plant. This could be explained by differences in light and in the maturity of the flowers.

Also interesting is the distribution of terpene content across the plant. Monoterpenes such as limonene and alpha-pinene repel insects and are found in higher concentrations in the flowers, while sesquiterpenes, which are bitter to mammals, are more concentrated in the lower leaves of the plant. The ratio of monoterpenes to sesquiterpenes also determines the viscosity of the resin.

Finding out exactly how the production of cannabinoids and terpenes is regulated in cannabis trichomes is what most captures growers' attention, and it is what breeding focuses on. If these unknowns could be unlocked, it would be possible to create cannabis strains with “à la carte” aroma and cannabinoid profiles.

Trichome colours: the sign that it's time to harvest

The colour of the trichomes is an important indicator for deciding the right time to harvest cannabis flowers. As the plant matures, compound production moves forward over just a few days, and the trichomes go from translucent to milky white, then to opaque white and finally to an amber hue. Growers watch these changes very closely, as they give valuable information about the best time to harvest.

*You'll find the practical guide with photos in *how to identify mature trichomes for harvesting.

Transparent trichomes

In the early stages of development, trichomes are usually translucent or pale. At this stage, cannabinoids such as THC and CBD have not yet reached their maximum concentration.

White or milky trichomes

As the plant approaches maturity, the trichomes start to turn opaque and take on a milky white colour. This change in colour shows that the cannabinoids are reaching their maximum concentration and that the inflorescences are reaching their peak of development.

The ideal time to harvest cannabis plants is when the trichomes reach a milky, opaque white, a balance between opacity and transparency. This colour shows that the cannabinoids and terpenes are at their optimal point for harvesting, in terms of quality and the desired effects.

Amber trichomes

When most of the trichomes have turned from white to amber, many growers spring into action as quickly as possible.

Amber trichomes are said to indicate a higher proportion of degraded cannabinoids and a more relaxing, psychoactive effect, while milky trichomes indicate a higher content of active cannabinoids and a more stimulating effect. In addition, the pistils or hairs on the buds usually turn orange or brown during senescence.

Handling buds and caring for trichomes after harvest

One of the most appealing sights for cannabis enthusiasts is a bud coated in sticky, resinous trichomes. But for this marvel to reach you in perfect condition, the buds must be handled with the utmost care during and after harvest.

Trichomes are delicate and can break during the harvesting, drying, curing and trimming of the buds. When they are damaged, their phytochemical content – the precious aromas and cannabinoids – gradually evaporates, to the detriment of bud quality. Keeping trichomes in perfect condition and storing buds properly is one of the biggest challenges for companies like ours that work with high-quality cannabis.

Freezing to better preserve trichomes and their phytochemical content

If you're curious, here is one of the most advanced techniques: freezing, which stops the oxidation and evaporation of cannabinoids and terpenes and preserves the cannabis compounds as fully as possible until the moment of sale.

Recently, technologies have emerged in the cannabis industry that use freezing as a method for separating and preserving trichomes. One of them is Cryo Cure, which uses freezing at subcritical temperatures and controlled sublimation to avoid traditional drying and deliver high-quality buds in less time. This technology removes the risk of physical damage inherent in cutting, curing and drying techniques, and allows faster production. CryoMass is another machine that uses similar technology.

In short…

Trichomes and the life that goes on inside them are truly fascinating for cannabis and hemp enthusiasts. These tiny sticky hairs hold pure alchemy: the chemical compounds of cannabis that we value so highly. Understanding their nature, watching how their colour and shape change, and taking care not to damage them when handling the harvest is key to enjoying cannabis.

At Cannactiva we've done the work for you. You can find top-quality CBD flower with potent trichomes (bear in mind that in some countries, such as the UK, hemp flower is controlled even when its THC is low):