The Importance of Trichomes in Cannabis
Trichomes perform several important tasks to maintain the health of their respective plant, but that’s not why humans like them. Chris Bond takes a deep dive into the tiny world of trichomes and explains why these fragile bodies are so important.
Trichomes: what are they? It is a word often thrown around when discussing the finer points of cannabis, but it can be confusing to know just what exactly they are and do. The word “trichome” is of Greek origin and means “growth of hair.” A dictionary definition of a trichome is “a filamentous outgrowth; especially: An epidermal hair structure on a plant.” They obviously aren’t really hairs; they’re microscopic structures found on plant surfaces, specifically plants’ epidermal cells. Under a microscope or loupe, they look like a field of stalk-like appendages with mushroom caps for hats. They are far from homogenous, though, and can have a wide range of appearances.
Trichomes can be single-celled or multi-celled. They might look like buds, scales, or even papillae, similar to what makes up the surface of our tongues. No matter their appearance, they perform very important functions on each plant contributing to various biological processes. They are thought to be highly specialized and self-regulating, so as to not interfere with the plant’s development apart from those functions they specifically perform. In other words, trichomes do their jobs and stay out of the way of other plant functions.
Trichomes are highly valued in many industries, not just the world of commercial cannabis. They are the source of many essential oils and resins. They are prized by the cosmetic, pharmaceutical, and agricultural industries that rely on certain extracts for their product lines. Not all trichomes are beneficial to humans, though. Some produce narcotic-like secretions, while others can cause skin abrasions and inflammation when they are touched. They do, however, serve the plants they are found upon very well, in many ways, that we are still now only just discovering.
How Trichomes Help Plants
Trichomes are found throughout the plant kingdom, serving many different roles. They perform protective functions, aid in biological processes, and can even help nourish the plant. On several species of flora, trichomes provide both physical and chemical protection to plant leaves against damage from insects and other microbial organisms. They also deter many types of leaf-eating animals from eating their plants’ leaves by imparting a bad taste.
Trichomes on the leaf surface form a porous barrier. This allows moisture to reach the leaf surface, but also blocks enough moisture from leaving to prevent desiccation (drying out) due to respiration. This function is known as turgor maintenance. Carbon is captured and assimilated by plants by way of some trichomes.
Trichomes also serve as sites of biosynthesis for secondary metabolites and stress proteins. Some trichomes even help carnivorous plants catch their prey.
There are two categories of trichomes that perform these varied functions for plants: glandular and non-glandular trichomes. Glandular trichomes produce or excrete different metabolites. Studies have shown the production of secondary metabolites (such as terpenes) can offer protection to plants under certain abiotic stress events. Glandular trichomes create these metabolites.
Non-glandular (also known as non-secretory) trichomes store toxic substances, preventing them from entering the plant’s system. Non-glandular trichomes also mitigate certain stress conditions. They are known to accumulate salts to help prevent salinity stress in plants when exposed salt levels that are too high. They isolate and store the salts so they can’t do harm to the plant.
Trichomes in Cannabis
The functions of cannabis trichomes have been well studied, with several benefits identified to help them survive in nature. The coating of sticky resin on the surfaces of leaves are a function of trichomes. This material is thought to be an initial deterrent to fungi, insects, and grazing herbivores. There are some species of insects and species of fungi that are not able to penetrate this protective layer. The taste of the cannabis leaves and flowers is also unpleasant to many animals thanks to the work of the trichomes.
Trichomes also help cannabis survive in a range of climates. The resin layer protects leaves from drying out in hot desert winds as well as from cold artic blasts. In regions where cannabis grows in the full sun, the same resin layer protects the plant from getting sun scorched by the sun’s intense UV rays.
Trichomes on cannabis are mostly not visible to the unaided eye. Many inexperienced growers incorrectly identify the hair-like strands that are found on the calyxes of flowering female cannabis plants as trichomes. There are, however, three distinct types of cannabis trichomes that can be seen and identified under magnification, or even under careful scrutiny to the trained eye. Learning some of the characteristics of them can be helpful to knowing when the ideal times for certain tasks are, such as harvesting.
The smallest cannabis trichomes are bulbous trichomes. They can be found all over the plant and are only 10-15 micrometers in size. The second-most commonly found group are the capitate sessile trichomes. There are more of these on cannabis than the bulbous type and are slightly larger. The biggest are the capitate-stalked trichomes and these are sometime large enough to be seen without magnification. They range in size between 50-100 micrometers wide. Cannabinoids and terpenoids are synthesized in the heads of these trichomes. The capitate-stalked ones are found on and near the calyxes of the flower buds and contain high amounts of essential oils.
As cannabis plants begin to transition from their vegetative stage to their flowering stage, cannabinoid synthesis in the trichomes begins in earnest. Trichomes start to appear more abundant and do the work of transporting materials that will eventually become cannabinoids. A range of factors dictate how quickly and to what extent each plant produces trichomes. Genetics and environment play a role. The amount and type of light affects trichome development and productivity greatly. Plants that are exposed to the fullest spectrum of light will typically produce cannabinoids of the highest concentrations, limited, of course, by the genetics of the individual strain. As trichomes continue to develop, their lifecycle mirrors that of the plant itself.
The maturity of trichomes can be determined by their color in many cases. They begin translucent in appearance, then transition to a cloudy white color, finally ending in a near amber tone. Once the trichomes have turned their amber color, it is time to harvest the cannabis flower. At this point, the trichomes are at their peak and if the flowers are not harvested in time, the trichomes will begin to degrade and their potency will diminish with it. This is an oversimplification, but generally holds true. There are some variations in strains, but as a rule, the color of the trichome can be used as a harbinger of when to harvest cannabis flowers.
Trichomes do so much to protect cannabis, but they are themselves quite vulnerable to damage. This is especially true during the post-harvest phase, even while still attached to a fully intact plant. They are prone to degradation by heat, light, and oxygen, but especially by physical contact. Left alone, time will eventually do them in to the point where they will offer very little to no cannabinoids or terpenoids.
It is important to protect the trichomes and the essential oils within them at all stages of growth, harvest, and post-harvest. This is primarily done by limiting any unnecessary contact or agitation of the flowers. Proper trimming, drying, and curing techniques must be observed to retain the integrity of all the cannabinoids and terpenes within.
Those looking to preserve trichomes beyond the life of the plant will need to engage in some form of extraction. This can be done in ways ranging from dry-sifting flower to produce kief, or chemically extracting the trichomes to create hash oil. With all the benefits that the tiny, fragile trichomes offer, it is worth the effort to save them whenever possible.
Ultra Trimmer is the only trimmer on the market that has been doing live demos since 2011 with a microscope, showing trichome preservation. To learn more, visit ultratrimmer.com or call 855-MY-TRIMMER.
Written by Chris Bond | Certified Permaculture Designer, Nursery Technician, Nursery Professional
Chris Bond’s research interests are with sustainable agriculture, biological pest control, and alternative growing methods. He is a certified permaculture designer and certified nursery technician in Ohio and a certified nursery professional in New York, where he got his start in growing.