In this edition of my column I'm looking back on one of the most important aspects of cannabis, the holy grail, the cream of the crop of cannabis: the glands, also known as trichomes. In my first column I've briefly gone over the subject, especially with the harvest focus in mind, and also the role that trichomes play. But this time I'm going to elaborate a little more on the subject of trichomes, the various species, the roles that they play and why they are so important regarding the cannabis cultivation. 

Trichomes, the moment of harvest.

Trichomes 60x Magnification

As mentioned earlier it's essential to determine when cannabis has ripened enough to be harvested since the maximum potential is reached when the plant is ripe enough. The flavor, scent and the effect of cannabis are determined on the moment it is harvested.  There's a significant difference between the potential and quality of ripe and non-ripe cannabis buds. The right moment of harvest differs per type of cannabis, but it also has to do with preference (the same thing goes for eating a ripe or almost ripe banana), keep in mind that it's not an exact science, only trial and error are the key to determine the perfect moment of harvest. But what do you have to pay attention to in order to find the perfect moment of harvest? The changing of the calyx hairs from white to reddish/brown? Or the discoloration of the green leaves to fall colors? No, you don't have to pay attention to this, although not to determine the right time to harvest anyway!

The only true indicator for maximum ripeness is the color of the (capitate-stalked) trichome heads. But what on earth is a capitate stalked trichome and where is the trichome head even located? This month I'll explain the anatomy of a cannabis trichome by means of an info-graphic, so you know exactly where the 'green gold' can be found! A magnifying glass or a microscope is essential to spot the trichomes, a mircoscope with 60x magnification can be found in our (online)store:

https://www.amsterdamseedcenter.com/en/high-grade-vision-microscope-60x-magnification (Note: this month we are running a promo where we give away the microscope for free when ordering above €50!)

 

Various types of Trichomes 

If you carefully look at the surface of cannabis with a microscope (the flowers, the leaves, the stems), then you'll notice a layer of rasin. This sticky layer, 'go touch a flowering cannabis plant with your fingers' is a manifestation of trichomes. Trichomes are the hairs/rasin glands of cannabis. A cannabis plant has various types of trichomes that can be distinguished into two categories: glandular and non-glandular. Glandular trichomes have glands (contrary to non-glandular trichomes), or little tiny balls where secretion of essential oils are taking place. Capitate stalked trichomes (the best known ones) Capitate sessile trichomes and Bulbous trichomes are all three responsible for the secretion of essential oils (Image 3C-F).

Capitate stalked trichomes (Image 3D) are the most important and best known ones because most of the essential oils are secreted in these types of trichomes. 

Sessile, Stalked, Bulbous Trichomes by David PotterFIGURE 3. Cannabis trichome types. (A) Unicellular non-glandular trichome; (B) cystolythic trichomes; (C) capitate sessile trichome; (D) capitate-stalked trichome; (E) simple bulbous trichome; (F) complex bulbous trichome. Images provided by Dr. David J. Potter.

 

Capitate-Stalked Trichome

A trichome, in this case the capitate stalked trichome, is simply a stick with a little ball on it. In this little ball alone, the 'head of the trichome' (resin gland), are the essential oils of cannabis stored. This means that the cannabinoids and terpenes, the two factors that largely determime the potential of cannabis are only present in the trichome heads. For those who are unfamiliar with terpenes: terpenes are the organic substances that make up the taste profile and aroma of cannabis. With that being said it can be concluded that the trichome-heads is the most important aspect of the entire cannabis plant. This is what you're working for, this is where your 'high' is coming from. This is where 'The Cure' is located, the only part of the plant where the (psycho) active ingredients are: 'The resin glands of Cannabis'!

 

Resin Gland Colors

The color of the contents of these trichome heads (resin glands) gives you an indication of the development of the cannabinoids and terpenes and if they have reached their maximum potential. Three different colors of the resin glands can be distinguished, this color varies (depending on the ripeness) between 'clear', 'milky' and 'amber'. Clear resin glands are often associated with unripe cannabis, because if the trichome heads are still transparant then they don't contain any (psycho-) active components yet. Milky is when the resin glands start to become cloudy, then there's a white substance in it. This indicates that the cannabis is almost ripe. The heads filled with a white substance indicates the presence of (pshyco-) active components, but no maximum ripeness yet.

Some opt to already harvest in this stage, I think that's a matter of preference since there are various levels of ripeness (color stage from milky to amber). Amber indicates a maximum ripeness of the cannabis, trichome heads filled with heavenly golden oils are ready for harvest. The different color stages affect the effectiveness of cannabis when consuming it, in other words the 'high' you will experience from it. In order to achieve its maximum potential I advise (note: my opinion) to harvest only when at least 50% of the resin glands have a milky color and a large percentage (20% - 30%) is amber, so the least amount of clear glands. 

 

Evolution of Trichomes 

Cannabis has evolved trichomes for various applications in nature. Aside from the fact that they contain cannabinoids and terpenes that you (and I) are so fond of, trichomes also play an important role regarding the entire life cycle of the plant:

  • Protects against insects/pests
    The trichome layer acts as a coating that insects find unpleasant, therefore they avoid the plant. Besides, insect could stick to it.
  • Protection against animals
    The trichome layer makes it much less appetizing for herbivores and omnivores. Still, many animals will have a go at it so there's no such thing as complete protection.
  • Protection against Fungi
    Some components that are present in the trichomes hinder/inhibit the growth of certain kinds of fungi.
  • Protection against UV-B light
    UV-B light (found in sunlight) is harmful to all living things, THC has feature that absorbs UV-B rays. This means that capitate stalked trichomes filled with THC acts like a natural sun screen against UV-B rays.
  • Protection against dehydration
    The layer of trichomes helps to isolate the cannabis flowers against excessive heat, strong winds and/or low humidity so the plant won't dry out.

The Green Gold - Glands of Cannabis 

Sources used for this article:

http://journal.frontiersin.org/article/10.3389/fpls.2016.00019/full

http://www.hempreport.com/issues/17/malbody17.html

https://www.icmag.com/modules/Tutorials/Harvesting%20and%20Curing/1529.htm

http://www.cannabisculture.com/content/2009/06/12/inside-trichome

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2931553/

https://www.medicaljane.com/category/cannabis-classroom/cannabis-science/#new-vs-old-science

http://cannabis.com/faqs/growing/curing-what-are-trichomes-trichome-101.html

http://www.gwpharm.com/uploads/finalfullthesisdjpotter.pdf

http://www.hightimes.com/read/anatomy-trichome

https://www.medicalmarijuana.com/the-trichome-by-matt-rize/