What are trichomes? Pretty, potent, and practical

What are trichomes?

Ever squatted down by a tomato plant and taken a big whiff? Even after the flowers have turned to fruit, the plant has an unmistakable aroma. This is partially due to trichomes, a word derived from the Greek tríkhōma, which means “hair.”

They often look like fine, microscopic hairs lining the stems or flowers of plants. Different kinds can also be found in algae and lichen. With how present they are in the garden, one might wonder, what are trichomes?

A close up of a ripe blooming female marijuana flower with visible trichomes of THC. Shallow depth of field and blurred background.

What are trichomes?

Biologists theorize that their primary function is to serve as a defense mechanism. That smell pouring from tomato or cannabis plants is often deeply attributed to trichomes. They are also the reason weed is called sticky-icky.

Glandular trichomes consist of a stalk and a head. The whole shape is reminiscent of a little mushroom. Most of the plant’s cannabinoids, terpenes, and flavonoids are stored in that glandular head, and these compounds are sticky to the touch.

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Terpenes are one way that a plant communicates with the world around it. Getting eaten by a specific bug? A plant will start growing a secondary metabolite that can physically prevent a pest from getting to the leaf to feast. Plants produce a terpene or combination of terps that cause predators to steer clear.

These stinky terpene-filled glandular head smells result from transcription factors binding to the plant DNA, it’s a biological mechanism of the plant. Since trichome development is a natural response to protect the plant, cannabis growers can use stressors like ultraviolet (UV) light to trick plants into growing more trichomes.

Types of trichomes

The type of trichome can differ based on the plant species. They can look like single hairs or branch out in a stellate formation. And when it comes to cannabis flower, they can grow in a few ways.

There are four types of glandular trichomes that emit cannabinoids, terpenes, and flavonoids.

  • Bulbous trichomes

As the smallest of the four options, bulbous trichomes are difficult to see. The tiny mushroom-shaped glands are made up of only a few cells.

They produce cannabinoids and are mostly found on plant material, like the underside of fan leaves.

  • Capitate-stalked

A capitate-stalked trichome formation is probably depicted in cannabis macro photography and fine art paintings most often. These are the largest of all the options and grow with a thick stalk and rounded mushroom head.

As the largest trichome, capitate-stalked grows the most extractable sticky compounds. Therefore, they’re of the utmost importance to cultivators and connoisseurs.

Growers keep their eye especially keen on capitate stalked trichomes during flowering stages. The plant is ready to harvest as soon as the heads turn amber.

What are trichomes?
Photo by Gideongs for Getty images
  • Capitate-sessile trichomes

Though not as coveted by artists, capitate-sessile trichomes may be just as crucial as capitate-stalked. This is because these short-stalked, huge-head-having glands produce cannabinoids. But, since they are invisible to the naked eye, they are often overlooked.

  • Antherial-sessile trichomes

These appear very similar to capitate-stalked trichomes, just smaller. They also produce cannabinoids and terpenes, which are stored in the glandular head resting atop a small stalk. Though they’re smaller than capitate-stalked, antherial-sessiles still store a lot of valuable cannabis compounds.

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There are also two kinds of non-glandular trichomes. There’s simple unicellular, which can be found all over the parts of the plant. These fine hairs with no glandular head are thought to serve as a layer of protection from UV light, wind, and bugs crawling on the plant.

Cystolithic trichomes are also non-glandular, appearing like spiky hairs on the leaves and stem of the plant. These are slightly barbed, like a cat’s tongue or bear’s claw. They serve a similar purpose as unicellular trichomes.

How do they affect the cannabis experience?

Terpenes are secondary metabolites found in high concentrations in trich heads. They are also found in almost all other plants, flowers, and some insects.

These compounds have a strong smell, evident in essential oils, which are made up of mostly terpenes. Everyone from scientists to connoisseurs believe terpenes can guide the cannabis consumption experience.

Their heads store terpenes. One will be made up of a wide variety of terpenes in different concentrations. These combinations contribute to the many unique aromas and effects of the cannabis plant. In fact, some believe the root of exotic weed is a novel terpene profile.

Because so many valuable compounds are in the trichome, growers, hashishins, and extractors take care when handling plant material. While the buds are on the plant, getting bagged, or being washed and made into extracts they must be handled delicately.

The best flower features whole, sparkling trichomes without many broken heads. Flower with pristine trichomes in higher concentrations also create the loudest extracts.

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Many believe that whole heads create a more enjoyable, impactful high. At the very least, cannabis products with robust trichomes will most likely smell and taste better.

As more research on the cannabis plant is conducted and made public, there will be a more concrete understanding of how terpenes, trichomes, flavonoids, and cannabinoids work together to get people stoned.

They can be valued for delivering crystal clear cannabis effects, keeping bugs from eating garden foliage, or capturing luscious scents. Whatever the reason, trichomes are important.

It doesn’t matter if the farm grows tomatoes or cannabis—they’ve probably keyed into the trichome production to understand how a plant communicates with its environment. As for the cannabis world, trichomes are essential from sprout to smoke.

Cara Wietstock is Senior Content Producer of GreenState.com and has been working in the cannabis space since 2011. She has covered the cannabis business beat for Ganjapreneur and The Spokesman Review. You can find her living in Bellingham, Washington with her husband, son, and a small zoo of pets.