Showcase: Trichomes

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Showcase: Trichomes

When it comes to assessing the cannabinoid content of bud, it is all about the trichomes. Find out what they are, what they do, and how you can use them to tell the optimal time to harvest here.

You may or may not have heard of them before, but trichomes play a huge role in the potency of cannabis. So whether you are a diehard marijuana enthusiast, or just someone who likes a bit of a smoke every now and again, knowing about trichomes can help understand what makes the difference between top-shelf weed and rubbish fodder.


Trichomes are little outgrowths that can be found all over a cannabis plant, but they grow most densely on its flowers. As gross as it may sound, you can think of these little growths as glandular hairs. It is in these hairs that the majority of the plants cannabinoids can be found - such as THC, CBD and THCV; although there is a small amount throughout the entire plant. It is why cannabis growers place so much emphasis on monitoring them, and why hashish, which is made from pressing trichomes into a cake, has the potential to be so potent and pure.

There are three main types of trichomes, these are:

Bulbous – The smallest of the three types, these trichomes are often only a few cells high, and secrete a resin that accumulates between the head and cuticle of the trichome. These bulbous trichomes are the least numerous of the three types, and can be found scattered across the entire above ground area of the cannabis plant.

Capitate-Sessile – This type of trichome is much larger than the bulbous trichome, producing large, spherical heads. Although larger, capitate-sessile trichomes tend to sit flush with the plant’s surface, only having a stalk one or two cells high. The head of each of these trichomes is made up of 8-16 cells, and produces cannabinoids that sit in its outer membrane – causing the spherical shape.

Capitate-Stalked – These are the trichomes that the majority of cannabis enthusiast are going to be most interested in. These are made up of a tier of secretory disc cells, which elongate during flowering – making them the largest and most noticeable of the three types of trichomes. It is within these trichomes that the most concentrated cannabinoid content can be found, hence them being the most appealing. They grow in the largest concentrations around, and on, the female cannabis’ flower – making this section of the plant the most potent for smoking.


Other than containing the rich abundance of cannabinoids that has so many of us watering at the mouth, trichomes play a much larger and varied role in the lifecycle of a cannabis plant.

UV-B Light – The UV-B rays found in natural sunlight are harmful to all living things. Thankfully, most life has evolved with ways of dealing with it. For the cannabis plant, this comes in the form of their trichomes, which act as a natural sun-screen.

Fungal Protection – Some of the compounds produced by trichomes have anti-fungal properties, offering a degree of protection in preventing infection in particular humid environments.

Insect Protection – Whilst it won’t stop all insects, many find trichomes and their compounds ‘unpleasant’ and will often leave cannabis plants alone.

Desiccation – Trichomes help protect cannabis plants from excess heat and wind, stopping them from drying out to rapidly – this is especially important for the female flower in adverse conditions.

Animal Protection – much in the same way they protect from insects, some herbivores find trichomes unpleasant when consumed, and tend to try and avoid them; but much in the same was as with insect protection, this is not absolute, with many animals not caring.


The first thing to understand when it comes to trichomes and harvesting cannabis is that dense trichome production doesn’t necessarily mean that the plant is going to be potent. It can certainly be an indication of it, as dense growth means more cannabinoids, but is no guarantee. For example, industrial hemp, which has been bred to contain very little THC and other cannabinoids can become covered in trichomes, but lacks potency. Actual potency can be affected by a whole multitude of things, such as genetics, and how well it has been grown.

Although trichomes don’t necessarily equal potency, they are the best way to tell when your cannabis is at its optimal cannabinoid content, and thus ready for harvest. This is done by observing the capitate-stalked trichomes as they grow, looking for changes in colouration.

The easiest way to do this is by using a 25x pocket microscope. Using this, capitate-stalked trichomes should be easily observable in great detail. As they grow, you should notice that they start out clear, changing to cloudy, and then amber as they mature. It is the transition from clear to cloudy that you want to look out for. When the majority of trichomes have changed, they are at their optimal level of cannabinoid content. Once the trichomes begin to change from cloudy to amber, the cannabinoid content has started to degrade.

It is important to mention that this clear – cloudy – amber process is not the same for all strains. Some few strains can actually start out amber, giving unprepared growers a small heart attack. What is most important to look out for is an initial change in colouration – once this has happened in a flowering plant, it is time get out the clippers.

Hopefully you now have a good idea of what trichomes are, and how they are useful to the cannabis plant, the people growing them, and the end user looking for a quality smoke – remember, you want dense amounts of cloudy trichomes; if you have this, you are onto a winner!