Trichomes on Weed: What, Why, and How

Trichomes are fascinating on many different levels. These dew-drop-like protrusions are gorgeous, but the real magic is inside. Their sticky contents are the source of all that is great about cannabis: cannabinoids, flavonoids, and terpenes. As a grower, it is essential to know about trichomes: Their development, function, and how they can improve your cannabis cultivation skills.

What are trichomes?

Trichomes are essential to the uniqueness, potency, and value of the cannabis plant. However, what are these tiny structures? The word “trichome” stems from the Greek tríkhōma, which means “hair”. This is a fitting name, as trichomes can seem like hairy outgrowths to the naked eye. They can be found not just on cannabis but on various plants, lichens, and algae. 

In the cannabis plant, they serve as microscopic factories that produce the plant’s potent compounds, including cannabinoids like tetrahydrocannabinol (THC) and cannabidiol (CBD), along with aromatic terpenes and other compounds that give weed its unique properties. They are the source of the sticky residue we call plant resin.

When do trichomes appear and what do trichomes look like?

Trichomes form in the earliest stages of a cannabis plant’s life cycle. However, they only become visible to us as the plant matures. A healthy trichome coverage can resemble a frosty, crystal-like coating that is particularly dense on the flowering buds. Their appearance and structure can resemble tiny mushrooms. Some trichomes feature a stalk extending from the plant’s surface with a gland head on its top, and inside, the fascinating process of cannabinoid synthesis occurs. 

Like with almost all other parts of the cannabis plant, trichomes can vary significantly across different strains. The plant’s genetics influence its size, density, and quantity. This considerably affects the plant’s potency, aroma, and flavour profile.

The functions of trichomes for the cannabis plant

So, why does the cannabis plant form all these small appendages? Trichomes are mainly responsible for the plant’s cannabinoid and terpene production. They constantly synthesise and store an array of compounds. In their insides, the well-known THC and CBD and their chemical precursors THCA and CBDA are found, as well as lesser-known cannabinoids like CBG, CBC, and CBV, and hundreds of other metabolites and compounds. 

The spectrum of compounds a trichome produces can be highly individual and significantly differ depending on the plant’s stage of maturity and genetic blueprint. This chemical cocktail acts as the plant’s natural defence mechanism. You can look at the trichomes as a protective shield, keeping threats at bay. For many herbivores, the contents of the trichomes taste bitter, and they quickly learn to stay away from them. 

The trichomes’ spiky texture helps protect the plant from environmental stressors, like harmful UV radiation, acting as a natural sunscreen. 

The benefits of trichomes for cannabis enthusiasts and growers

For cannabis growers, trichomes are one of the most essential plant elements to watch out for. The type and quantity of cannabinoids and terpenes produced can significantly impact a strain’s characteristics. This includes its potency, aroma, and flavour. 

The composition inside the trichomes can make the difference between a mellow, relaxing strain and one that provides an energetic buzz. By selecting parent plants rich in trichome production, breeders can crossbreed strains to achieve a higher potency, specific flavour profiles, or tailored therapeutic benefits.

The appearance of trichomes is also crucial in determining the optimal timing of the harvest. Skilled growers are always in tune with trichomes’ life cycle and growth stages. Just by looking at them, they can pinpoint the perfect time to harvest their plants for maximum potency. Trichomes signal their maturity with visible changes — more on that below.

What are the four main kinds of cannabis trichomes?

1. Capitate-stalked trichomes

These are the most popular trichome types with their characteristic mushroom shape and comparatively large size. They consist of a stalk and a glandular head. They are approximately 50-100 micrometres (or microns) wide (0.05 – 0.1 mm) and can get 200-300 microns tall (0.2 – 0.3mm). This makes them visible to the human eye. Within them, they produce all cannabinoids, terpenes, and flavonoids. Capitate-stalked trichomes are primarily responsible for the frosty appearance of weed.

2. Bulbous trichomes

These are the smallest trichomes, measuring about 10-15 micrometres. Due to their minuscule size, they are almost invisible to the naked eye. Under the microscope, they appear like little bubbles. Despite their size, bulbous trichomes cover the entire plant surface, including the leaves and stem, playing a crucial role in producing cannabinoids, terpenes, and flavonoids.

3. Capitate-sessile trichomes 

Capitate-sessile trichomes look a bit like button mushrooms under the microscope. They range between 25-100 micrometres and cover cannabis plants even more densely than their bulbous counterparts. Regarded as the second most prevalent trichome type, they are found on stems, leaves, and bracts. Although they manufacture cannabinoids and terpenes throughout the plant’s lifespan, the potency levels are not relatively as high as those of the capitate-stalked trichomes. 

4. Cystolithic trichomes

These trichomes are different from the other three types because they are non-glandular. This means they do not have a bulbous head to store plant chemicals. Instead, cystolithic trichomes resemble short spiky hairs and have a claw-like appearance. They have a microscopic length of about 50 microns and produce fewer chemicals than their bulbous and capitate-stalked cousins.

Monitoring the different stages of trichome growth

If you want to get the most out of your cannabis harvest, you should look closely at the development of the trichomes, especially on the flower buds. Checking their quality and colour will tell you exactly when the perfect harvesting window has opened. 

You can get a general impression of the stage and quality of your trichomes by looking at them with the naked eye under sufficient lighting. Nevertheless, having a loupe or microscope in your grower’s toolkit would be best for closer inspection. Jeweller’s loupes are excellent for this. 

There is also a range of digital microscopes available for this exact purpose. Macro lenses that can be attached to smartphones can also help here. The fascinating microscopic landscape of your favourite plant might also inspire you to do stunning macro-photography!

What do trichomes look like when ready to harvest? The three stages of trichome maturation

1. Clear stage

Trichomes start their life cycle looking like clear, tiny mushrooms. Clear trichomes indicate that the plant is still growing and has not yet reached its full potential. Harvesting your weed plants while the trichomes are still translucent would be somewhat early. Cannabinoids and other compounds have yet to be synthesised in more significant concentrations. These clear-headed trichomes might still produce effects but are less potent than their mature cousins. 

2. Cloudy stage

As trichomes mature, they transition from a clear to a cloudy, milky white appearance. This is a telltale sign that the THC content is at its peak. If you harvest at this stage, your buds will evoke an intense, energetic high. However, other cannabinoids, like CBD, CBG, and certain terpenes, have yet to evolve. For a more complex profile, you might want around two weeks longer.

3. Amber/brown stage

During the final phase, trichomes become more colourful, shifting towards deep brown and amber hues, indicating the development of essential compounds. If you want to cultivate plants with a broad spectrum of cannabinoids, terpenes, and flavonoids, this is the right stage to harvest your plants. Flowers with a plethora of amber or brown trichomes tend to have more relaxing, calming properties, which are ideal for recreational and medicinal users. 

How to increase trichome growth?

It should be clear by now that keeping an eye on the trichomes is critical to an optimal cannabis harvest. Nevertheless, how to improve and optimise the production of this crystalline gold? 

The first step towards a stellar harvest with the highest possible trichome quality is to choose the suitable strains for you. The latest developments in cannabis genetics have brought forth varieties geared towards optimal and dense trichome growth. The results are exceptional flowers with individual blends of fragrances, aromas, effects, and benefits. 

Once you have decided to cultivate one or more strains, it is time to refine your growing techniques. Most growing instructions that aim for high quality and rich harvest, including high terpene levels, also focus on high trichome production. 

Here are seven tips for growing techniques to boost your trichomes:

1. Choosing strains naturally high in trichomes

When maximising trichome production, selecting the appropriate genetics is crucial. Although all cannabis plants produce trichomes, some strains appear more frosty than others. These are the top five strains that produce an abundance of trichomes: 

• White Diesel: The lineage of this strain is quite potent, and during flowering, White Diesel Haze develops an abundance of trichomes that give the flowers a frosted appearance. It has a pungent Diesel aroma and provides an uplifting cerebral high.

• Jack Herer: Well-known for its abundant resin production. Its genetics encourage significant trichome development, contributing to its reputation as a well-balanced strain that combines cerebral stimulation and physical relaxation.

• Wedding Cheesecake: This strain boasts trichome-rich buds and a cannabinoid profile that is robust and complex. Its aroma is reminiscent of cheese but has a subtle sweetness that adds to its appeal.

• N13 Kush: Known for its ability to produce heavy yields and powerful effects, N13 Kush features abundant trichomes production and is a homage to its Afghan genetics.

• Sticky Orange XXL: An exotic cultivar that boasts oversized, resinous buds covered in a thick layer of trichomes with a distinctively citrusy flavour profile.

2. Lighting

Your choice and arrangement of lights can directly influence trichome development. As mentioned before, the trichome coverage works like a protective sunscreen for the plant; just like how our skin produces melanin as a shield against the sun’s damaging rays, cannabis plants ramp up their production of cannabinoids in response to UV-B exposure. 

Growers utilise this behaviour to boost trichome production by maximising UV-B radiation. Light-emitting ceramic (LEC) and UV lights are the best tools. More on the perfect light conditions for weed here.

3. Environmental conditions

Trichomes love a balanced environment, and optimal environmental conditions, including temperature, humidity, and airflow, are vital. To optimise trichome production, it is recommended to maintain temperatures between 18°C during the evening and 23°C under the lights. Excessive humidity levels can dramatically increase fungal disease risk, and maintaining a relative humidity of around 50% is advised. 

4. Growing supplements

Healthy plants mean a healthy harvest! Just as you would take your vitamins, certain supplements and organic fertilisers can give your weed an extra trichome-boosting push. Some supplements you might want to add to your soil contain amino acids and lactic acid bacteria. 

Molasses are also a great source of sugars that can provide the energy for trichome production. Always remember that cannabis will need different supplements throughout the different stages of plant development. 

5. Defoliating

Defoliating ensures that lower buds get more light, removes non-essential leaves and helps the plant direct its resources towards flower formation and trichome development. However, be warned, as excessive pruning can stress your plant and hamper its growth. 

6. When to flush based on trichomes

Growers recommend flushing your plants with generous amounts of clear water throughout your cultivation cycle. Flushing helps remove the medium’s unwanted salt residue, which can leave an unpleasant taste in the finished harvest. 

7. Curing

Curing has a tremendous effect on trichome development. Excess moisture is removed in this phase, and the compounds change composition, helping trichome preservation. Initially, trichome levels decrease, but after the eighth week of curing, they return even more robust. During the curing process, relative humidity should be maintained between 45% and 55%. The temperature should be between 20-22°C. 

Proper curing does not just maintain trichomes; it amplifies them, contributing to a more fragrant, potent cannabis harvest.  

Trichomes, more than just a resin gland

Trichomes, the minuscule structures on cannabis responsible for producing cannabinoids like THC and CBD, terpenes, and flavonoids, play a crucial role in a plant’s potency and aroma. The appearance of trichomes, and their transition from clear to amber, are vital indicators for optimal harvest time.

The concentration of compounds within the trichomes depends on the cannabis strain and growing conditions. Their maturation process, which involves turning from clear to a cloudy or amber hue, indicates the peak time for harvest. The transition to amber can take several weeks, depending on the strain and environmental factors.

To optimise trichome production and preserve potency during harvesting, you should maintain balanced environmental conditions, provide adequate UV-B light, and apply proper supplements. After harvesting, you can further increase the potency of the cannabinoids in the trichomes by curing your buds properly for several weeks or even months. 

Do you have any tips about improving the trichome contents? Let us know in the comments below!