• Post last modified:August 7, 2022
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We are experiencing a global cannabis renaissance. A once feared and downplayed plant is now being looked at with a fresh perspective. The stigma is rapidly evaporating, and more people are interested in learning about cannabis – its multiple benefits and anatomy. One of the most exciting and vital aspects is trichomes on weed. These cannabis structures are single-handedly responsible for the smokeless trend in cannabis culture that has largely diversified how cannabis is consumed. So, what are trichomes?

Trichomes are tiny, shiny, mushroom-shaped appendages that can be found on cannabis buds, leaves, and stems. Trichomes are made of hairs, papillae, and scales and are responsible for the frosty/crystalline and sticky characteristics associated with cannabis buds. When you look at flowers/buds up close through a magnifying glass, you will notice lots of tiny bulb shaped heads supported by a stalk. Trichomes are the powerhouse of cannabis plants, by which cannabinoids, terpenes, and flavonoids are created. Without these tiny structures, cannabis would not have the taste, aroma, and high that we all love and appreciate. 

Cannabis bud with a zoomed in view of trichomes on weed
Cannabis bud (left). Zoomed in close-up look at trichomes on weed (right)

This is just the surface of what trichomes have to offer though. This piece explores everything there is to know about trichomes, including their functions, how they influence potency, where they are located, how to increase their production, and when to harvest cannabis at the perfect time according to trichome appearance. Let’s begin…

What do trichomes do? 

There are two types of trichomes on weed: non-glandular and glandular, each of which plays a vital role in the survival and potency of the plant. 

Glandular trichomes

Glandular trichomes play a critical role in cannabis plants because they are the primary essential oil producers and contain the most THC. Cannabis plants have the following 3 glandular trichomes;

Bulbous trichomes

Bulbous trichomes are tiny, microscopic trichomes that give buds the characteristic shiny appearance and stickiness. 

Capitate sessile trichomes

Capitate sessile trichomes are more prevalent compared to bulbous trichomes. Although larger than bulbous trichomes, they are still not visible to the naked eye. The majority of these trichomes are located on the sugar leaves and fan leaves. These mushroom-shaped structures are responsible for producing a portion of cannabinoids and terpenes. 

Capitate stalked trichomes

Capitate stalked trichomes are the most abundant trichomes in cannabis plants. These structures act as the primary producers and storage for cannabinoids and terpenes. Capitate stalked trichomes are large, mushroom-shaped, and can easily be seen with the naked eye. At the base of these structures are secretory cells that transport nutrients to the top of the head through a stalk. If you are looking for THC or CBD, this is where they are concentrated. 

Non-glandular trichomes 

Also referred to as cystolithic trichomes, non-glandular trichomes are appendages or protrusions in cannabis plants that act as the primary physical defence of cannabis plants against external factors (biotic and abiotic). They do not produce psychoactive effects and appear earlier in plants compared to glandular trichomes. Physically, cystolithic trichomes have the same attributes as glandular trichomes without the bulb-like top. 

What are the functions of trichomes?

What percentage of THC is in trichomes? 

THC, CBD, and other cannabinoids are synthesized and stored in the trichomes on weed flowers. This means that all of the THC in cannabis plants can be found in the trichomes. The cannabinoids are concentrated in the capitate-stalked glands on female flowers’ bracts and the sugar leaves. Most of the THC can be found in the structural components within the secretory glands. 

Where is THC found on cannabis plants? 

THC is found in trichomes located across the entire plant. However, it can be found in abundance in cannabis flowers and trace amounts in leaves and steams. The average THC content in flowers ranges between 15% and 20%. You will find some flowers with less than 15% THC, while most surpass the 20% mark. For example, a strain like Godfather OG has soaring THC levels of 34% in its buds. The average THC on leaves is 1% to 3% and 0.1% to 0.3% on stalks. 

The potency of a cannabis plant is determined by two factors: genetics and environmental factors. When a potent strain is subjected to optimum growing conditions, it easily attains its full potential to provide an intense high, and potent therapeutic benefits. 

Do male cannabis flowers produce trichomes?

Yes. Male cannabis plants are not devoid of THC. Although they are less potent than female plants, male plants contain trace amounts of trichomes in their leaves and stems. Besides facilitating pollination, the plants are used to make hashish and other concentrates and can contain from 0.1-0.5% THC.

What do trichomes look like when they are ready to harvest? 

Trichomes undergo a series of color changes from their development to maturity. 

  • A clear/translucent hue indicates under ripeness. The trichomes are immature and lack potency since they are still forming THC. 
  • A milky white hue indicates ripe and healthy trichomes. This is when they are at the peak of cannabinoid production. The high provided by these trichomes is uplifting, stimulating, and energizing high.
  • An amber hue indicates maturity and the end of the plant’s growth cycle. The amber color is produced when the cells responsible for creating cannabinoids and terpenes begin to disintegrate. At this point, the buds have a sedating, couch lock effect. 

Trichome Harvest Chart

Trichomes harvest chart
Trichome harvest color chart

When to harvest cannabis based on trichome appearance?

The ideal time of when to harvest cannabis depends on the grower and the intended effects. Some growers like to harvest when all the trichomes on weed flowers have turned a milky white, this is known to be best for cerebral-centered effects. Most wait until the milky white and amber trichomes have a 70:30 ratio. Buds harvested at this time provide a perfect balance of cerebral and body-centered effects. For a more sedating effect, a few growers wait until there is a 50/50 distribution of milky white and amber trichomes. The sedating properties result from CBN, a cannabinoid that forms from the degradation of THC. 

Breeder assessing when cannabis buds are ready for harvest with a magnifying glass
Breeder assessing when cannabis plant is ready for harvest using a magnifying glass

What color trichomes have the most THC? 

If like many growers your aim is to grow the highest THC cannabis strains, then you will want to harvest them when they are at the peak of THC production. This window typically only lasts for a couple of weeks so you need to know what to look out for. Cannabis plants reach their peak cannabinoid production when trichomes are milky white hue. At this point, the trichomes are most potent/have the most THC. The trichomes remain milky white for up to 2 weeks while trying to make as many cannabinoids and terpenes as possible. To get the most THC, wait until the plants have finished synthesizing cannabinoids, right before the cannabinoid secreting glands begin to die. 

When does trichome production stop?

Trichome production remains steady throughout the flowering stage and rapidly increases as harvest increases. When the plants attain maturity, trichomes cease producing phytochemicals, and the cells responsible for terpene and cannabinoid secretion begin to die. Consequently, the bulbous heads of the trichomes begin to turn amber as an indication of maturity (the cannabis plants become harvest-ready). 

Can you increase trichome production?  

Every cultivator growing cannabis is after one thing: growing potent and healthy cannabis plants. As a result, they are always looking for a way to maximize trichome production. Below is a highlight of things you can do to increase trichomes on weed;

  • Low-stress training and high-stress techniques: subjecting the plants to reasonable, good stress activates their defence mechanism, leading to increased trichome production. These techniques involve manipulating the shape and size of cannabis plants to facilitate the equal distribution of growth hormones and light. There is a thin line between good and bad stress: knowing the difference is key to a bountiful, potency harvest.

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Low-stress training techniquesHigh-stress techniques
ScrOGSuper cropping
SOGmainlining
Bending and tyingTopping and fimming
lollipoping
  • Adjusting temperature and humidity setting: during the last two weeks of flowering, you can adjust the night temperatures to 15-16°C to create the illusion of winter approaching. Daytime temperatures should steadily remain under 25°C. Couple the temperature adjustments with lowered humidity levels between 35% and 40%. These conditions induce some stress that will accelerate trichome production. 
  • Administer proper nutrients: during the flowering stage, the plants require nutrients with high Phosphorous and Potassium content. These macronutrients facilitate flower growth, maintain the genetic integrity of the grown strain, and stimulate the rapid absorption of other nutrients by stimulating the root system. 

Factors that can prevent trichome production

As a cannabis grower, you must plan vigorously before beginning the cultivation process. Conduct proper research on the strain of choice to identify its genetic disposition: is it a trichome-producing monster or not? Unfortunately, unsuitable genetics will produce unimpressive yields, no matter the amount of time and effort one puts into the cultivation process. Another factor to consider is the environmental factors. As you grow your cannabis plant, invest in a remote monitoring system to ensure that factors like humidity, PH levels, and temperature are always at optimum levels. 

Even with good genetics, unfavourable growing conditions hinder trichome production and the plant’s health. A plant with poor health due to deficiencies, a surplus supply of nutrients or water, pests, and diseases will be impossible to attain its true genetic potential. Lastly, continuous contact compromises the integrity and potency of the fragile trichomes. 

REFERENCES:

  1. Chemical fingerprinting of single glandular trichomes of Cannabis sativa by Coherent anti-Stokes Raman scattering (CARS) microscopy

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