What are cannabis trichomes and how do they affect your smoke?
Trichomes are the source of resin and cannabinoids in your cannabis plant. They are small spheres of cannabis resin which coat the leaves, buds and branches of your cannabis plant, giving it a frosty white appearance. Cannabis trichomes are resin glands which allow the production of cannabis concentrates such as shatter, cannabis oil, hash, wax etc. Most people don't realise that there are different categories of trichomes, each with their own size, shape and unique biochemical function.
What are trichomes?
Trichomes are the small, hair-like growths which are found on plants (including cannabis) as well as lichens, algae and other protist organisms. A protist organism is one that has cells with nuclei, but is neither animal, plant or fungus. Examples of protist organisms include protozoa (‘animal’-like organisms) as well as certain moulds and plant-like protophyta.
Cannabis trichomes have a shape similar to a mushroom. A stalk supports a bulbous, spherical head. They are tiny too, at around 50-100 microns wide (1mm=1000 microns). Although trichomes are thought to have evolved with different functions, cannabis seems to use them to help defend itself.
The different types of trichomes found in cannabis
Bulbous trichomes tend to be the smallest type of trichomes. Sometimes these are as little as 10 microns wide, a fraction of the size of the largest. Bulbous trichomes can be found across the full surface of the plant, but because they are made from just a small number of cells they are difficult to see.
Capitate sessile trichomes
Capitate sessile trichomes are larger than the bulbous trichomes, with sufficient cell numbers to form a trichome head and a very short base. But with a width of around 20-30 microns they are not as large as the final category of trichomes, nor as easy to see.
Capitate stalked trichomes are the largest trichomes. For cannabis growers, these trichomes provide the bulk of the resin, THC and other cannabinoids. The width of our beloved capitate-stalked trichomes is around 50-100 microns. They can be 200-300 microns (0.2-0.3mm) tall. This is large enough to see with the unaided eye. Female cannabis plants, in particular, have large quantities of capitate-stalked trichomes.
You will notice that capitate stalked trichomes have a stalk which is made from cells known as epidermal and hypodermic cells. On top of the stalk is the head of the resin gland, the ‘capitate’. The ball-shaped head of the resin gland has a waxy outer cuticle layer which acts as a ‘skin’. Inside the resin head are the cannabinoids and terpenes. These are produced by specialist cells in-between the top of the trichome stalk and the spherical resin head.
As the cannabis plant ages and approaches harvest point, the resin glands can change colour. They change slowly from clear and colourless, to milky and eventually amber/red coloured.
Note that some cannabis seeds, such as Auto Blackberry Kush, can produce deep blue/purple colourations to the buds and leaves. Some of these colours can also appear in the trichomes.
Simple unicellular trichomes
Simple unicellular trichomes are non glandular. This means that you see a microscopically thin hair-like extension protruding from the plant surface, but without a spherical resin head on top. These trichomes are thought to offer basic plant defence. They make it tougher for insects and pests to damage the plant. They may also offer some protection from wind and light. You can find unicellular trichomes both on the upper and lower side of leaves.
Cystolithic trichomes are also a type of non glandular trichome, they don't have a resin head and are similar in appearance to simple unicellular trichomes. Cystolithic trichomes often take the shape of slim, curved hairs. The curved nature of these trichomes resembles the curved shape of a bear claw if you see several cystolithic trichomes in a row.
Antherial sessile trichomes
Antherial sessile trichomes are not quite as large as the capitate stalked trichomes which we are, perhaps, most familiar with. The width of them is around 80 microns. These are glandular trichomes, meaning that a resin head sits on top of the stalk.
Just like the capitate stalked trichomes, the antherial sessile trichomes have basal tissue underneath a disk of secretory cells (which produce the terpenes and cannabinoids) and a ‘head’ where the terpenes and cannabinoids are stored.
The influence of trichomes on cannabinoids and terpenes
Special cells produce secretions of terpenes and cannabinoids which are stored in the spherical resin gland in the trichome. The exact nature/ratio of the cannabinoids and terpenes secreted is determined by the genetics in the original cannabis seed, as well as the environment.
Many people that grow cannabis seeds do so for the THC content. Most cannabis strains have THC levels of around 15%. If you want higher levels then check out Dutch Passion’s collection of ‘Very High THC seeds’. If you really love maximum strength cannabis with THC levels around 20-25% then please check out Dutch Passion's ‘Extremely High THC seed collection’.
It’s worth adding that modern cannabis is much more than just THC. Many medical and recreational cannabis growers love to have some CBD in their buds. This often produces a more rounded and enjoyable vaping/smoking experience and is preferred by many. If this sounds like you then you may be interested in CBD rich cannabis seeds.
Anyone interested in feminised CBG seeds or THCV seeds should check out Dutch Passions ‘Special cannabinoid seed collection’. CBG-Force (feminised CBG rich seeds) and Auto CBG-Force seeds are available. So are THC-Victory seeds (feminised THCV rich cannabis seeds).
The terpenes produced by each cannabis strain are also determined by the genetics and environmental conditions. The terpenes add great taste and flavour to your cannabis. They may also modulate the type of high you experience.
Trichome production and lifecycle in cannabis
Cannabis trichomes ultimately provide a source of great pleasure and relaxation to humans. They are also a source of precious medicinal compounds. But for cannabis plants, trichomes offer valuable defensive properties which help them survive long enough to produce seeds for the next generation. Trichome production is vital to the cannabis lifecycle.
The sticky trichome coating acts as a physical barrier to deter pests and predators. Terpenes present in the cannabis trichomes are also a highly offensive scent deterrent to pests. The resinous trichome coating is also thought to protect delicate plant tissues from the damaging effects of UV solar rays. The cannabinoids found in the trichome layer are thought to have a chemical deterrent effect on insects and predators.
When do trichomes usually appear on cannabis?
Although most growers start closely examining the colour of their cannabis trichomes towards the end of harvest, the trichomes are present on cannabis in smaller quantities from being a young plant, though some of these will be invisible to the naked eye. As the plants ages, the trichomes increase in quantity and start to become most noticeable midway through bloom.
For most growers, the denser the trichomes, the better. Towards the end of bloom, if you started with the best cannabis seeds, you will see a thick resin crusting of trichomes on the buds and the leaves. This can give a white/silvery, appearance to your blooms. If you squeeze the buds, the oils and terpenes in the resin head burst out onto your fingers producing a great aroma.
How to check the production of trichomes?
Most growers examine their plants with a small magnifying glass (sometimes called a ‘loupe’). This makes it easier for the eye to see the developing trichomes. Some growers like to complement visual appearance with the use of aroma, and will monitor changes in their plants according to changes in aroma type (and intensity).
If you are growing from clones of a known mother plant, or if you have selected your cannabis seeds wisely, you will find that trichome production increases steadily as harvest approaches producing a crop of high quality cannabis buds.
When to harvest cannabis trichomes?
Much depends on your personal taste. One of the great advantages of growing your own cannabis seeds is that you determine the precise harvest point. For some people, early harvests offer a lively, energetic type of high. The trichomes will still be clear and colourless at this point. Although yields are not yet at their peak, for some growers there is nothing quite as good as early harvested cannabis.
Perhaps most growers tend to wait until the majority (around 70%) of their trichomes are milky/cloudy in appearance, with the first signs of some (perhaps 30%) turning amber. This also allows yields to increase slightly compared to early harvests with clear/colourless trichomes. The high becomes more rounded with stronger body effects. For some recreational and medical cannabis users this is a perfect blend.
Some growers prefer to wait until most of the trichomes are starting to turn amber/red. The cells that secrete cannabinoids and terpenes are starting to die at this point causing the trichomes to turn amber. The resulting cannabis tends to have a heavy, stoney feeling with strong body effects. For some medical marijuana users and recreational users that love a knockout stone, late-harvested is simply unbeatable.
When you buy cannabis you rely on someone else harvesting and curing it just the way you like it. That can be a lottery. When you grow your own cannabis seeds you have full control over the genetics, environment, harvest time and curing. That’s why more people than ever grow their own weed at home from cannabis seed.
How to produce more trichomes on cannabis
Environmental conditions and selection of your cannabis seeds are the biggest factors which affect the trichome levels on your cannabis. If you start with low-THC cannabis seeds then the genetics prevent you from reaching the highest THC levels. Choose your cannabis seeds wisely. Your two main options to start with are autoflowering seeds or feminised cannabis seeds. Regular cannabis seeds are another possibility, but they tend to be used by a small minority of growers.
Buy the best cannabis seeds
When you select your cannabis seeds, do your research carefully. The best cannabis seed companies have active social media channels for you to see the type of real-word results to expect. You may prefer to use seed companies with a long track record in innovation and cannabis cup wins to reassure you that you are dealing with premium marijuana genetics.
Use of LED grow lights
Many modern cannabis growers have found new quality levels after upgrading from HPS to LED grow lights. Many professional licensed cannabis growers would never grow with anything other than LED. Side by side grows of identical clones shows that THC levels are often 20-30% higher when grown under LED compared to HPS. That’s because LED delivers a superior light spectrum and lower levels of heat stress.
Use of UVB lights for cannabis cultivation
Adding supplemental UVB light during bloom is another way to boost cannabis trichome production. Trichomes have evolved partly as a defence to UVB radiation. So adding extra UVB boosts trichomes. It’s a technique used by many professional growers. Most growers use UVB lights for 2-3 hours per day in the last 2-3 weeks of bloom. Note UVB is extremely damaging to human eyes and skin. Never look in your grow room, or enter it, when the UVB lights are on.
Trichomes: the building blocks of cannabis extracts
Cannabis extracts and cannabis concentrates all rely on trichomes. There are various ways to make cannabis concentrates and extracts such as hash, shatter, cannabis oil etc. Solvent extraction uses solvents such as ethanol or IPA to dissolve the oily cannabinoids and terpenes and remove them from the plant tissues. The solvents need to be fully removed before the cannabis extracts are safe to use.
You can also make cannabis extracts without solvent. Rosin can be made by pressing dry cannabis buds between heated metal plates under pressure (hair straighteners with greaseproof paper also works).
Hash can be made with various methods, such as the water/ice method. But whichever of the many methods you use to make cannabis extracts they all rely on the cannabis trichomes being harvested/used.
Frequently asked questions about trichomes
Since trichomes are such a valuable part of the cannabis plant there are always lots of questions about them and how to maximise the amount of resin produced. Here are some of the more common questions we see:
What can cause a cannabis plant not to produce trichomes?
Low quality genetics or poor environmental conditions are the two main causes. There are plenty of poorly bred cannabis seeds with substandard genetics. If you grow these, it doesn't matter how good a grower you are, trichomes simply wont be produced in the desired quantities.
The other main cause of plants not producing trichomes is when the plant is in poor health and has been grown in substandard conditions. Even with good genetics, if the conditions are poor the plant can't express its true genetic potential. Some of the more common causes include over/under feeding, waterlogged roots, temperature/humidity extremes, pests or disease.
How to optimise your grow room
Can you smoke the trichome heavy leaves at the end of flowering?
Cannabis lovers enjoy the sweet tasting buds grown on their cannabis plants. The best cannabis seeds produce a generous coating of trichomes on the leaves too. Some growers smoke the most resinous fan leaves, but not everyone likes them. Some find the leaves can have a slightly bitter taste. That’s why many growers prefer to dry the fan leaves and use them for making cannabis concentrates or cannabis extracts.
How to take pictures of cannabis trichomes?
Some people love cannabis photography, especially up-close macro pictures of the buds at harvest. You can get attachments for your camera phone which give good macro images. Or you can buy a digital camera with a macro function to do the job.
Cannabis trichomes, pleasure and joy for the home grower
All growers love their trichomes. The more, the better. As more and more people grow their own cannabis seeds, interest in improving and optimising harvest quality is at an all time high. Trichomes are the source of the cannabinoids and terpenes that characterise the quality and satisfaction delivered by cannabis. To grow the best cannabis you need to combine high quality cannabis seeds with an optimised grow environment. As you gain experience your harvests will steadily improve. Remember to choose the best cannabis seeds you can from a seed company you can trust, and enjoy growing!