What Are Trichomes

Cannabis resin glands are called "trichomes". These little lovelies begins to develop as soon as the plant starts growing, but the real explosion of trichomes comes during ing.

Why Did Trichomes Evolve in Nature?

Trichomes protect the plant, flowering and especially the developing seeds from insects, animals, environmental conditions and diseases. The cannabis and various components of essential oils lend their protective qualities to these glands.

Insects Protection: many insects find the thick sticky coating of trichomes unpleasant. Others get caught in the sticky trichomes. Some of the cannabis oils posses repellent qualities to various herbivores. This offers a layer of protection from infestation by certain insects. It is especially useful for guarding the developing seeds.

Animals: the THC and other oils that make up the contents of trichomes have psychotropic that many mammals and other herbivores find unpleasant. This makes cannabis less palatable to many herbivores & omnivores. Fewer snackers means more chance of survival an reproduction.

Desiccation: Trichomes help to "insulate" the pistilate (female) flower from low humidity levels and high winds.

UV-B Light: UV-B is a form of ultraviolet light that can be harmful to living things, THC has very high UV-B absorption properties and more THC is produced in high UV0B light conditions. This implies that THC provides the plant with some protection from this harmful light.

Fungal and Bacterial Protection: some of the oils components present in trichomes inhabit the growth of fungi and bacteria.

Trichomes Structures

While structurally diverse, trichomes tend to come in three basic variants.

Bulbous: the bulbous type is the smallest (15-30 micron) trichome style. One to four cells make up the "foot" and "stalk", and one to four cells make up the "head" of the gland. Head cells secrete a resin – cannabinoids and various Terpenes which accumulating inside the balloon-like head cells. When the gland matures, a nipple-like protrusion may form on the membrane from the pressure of the accumulating resin. The bulbous are found scattered about the surfaces of the above-ground plant parts.

Capitate-Sessile: the second type of gland is much larger and more numerous than the bulbous gland. These trichomes are called "capitate" which means having a globular-shaped head. On immature plants, the head lie flush, appearing not to have a stalk. For this reason they are technically called "capitate-sessile". They actually have a stalk but it is only one cell high, so it is scarcely visible beneath the globular head. The head is usually composed of eight cells, but can be up to sixteen cells, and forms a convex rosette. These cells secrete cannabinoids and Terpenes, which accumulate between the rosette and it outer membrane. This gives it spherical shape. The gland measures from 25 to 100 micron across.

Capitate-stalked: during flowering, the capitate glands that appear on the newly formed plants parts take on a third form. The "capitate-stalked" gland consists of a tier of secretory disk cells which is topped by a large secretory cavity. Some of the same glands are raised to a height of 150 to 500 micron when their stalk elongates.

Cannabinoids are found abundance in the "capitate-stalked" glands form their densest cover of the female flower bracts during flowering. They are also highly concentrated on the small leaves that accompany the flowers. The male flowers have stalked glands on the sepals, but they are smaller and less concentrated than the female bracts. Male flowers form a row of very large capitate glands along the opposite side of the stamen.

When to Harvest Trichomes

We are most concerned with the capitate-stalked trichomes, as these contain the overwhelming majority of the psychoactive cannabinoids, of which Delta-9 THC is the star.

Heavy trichome production is not necessarily an indication of a potent plant. Some hemp strains have moderate layers of trichomes yet only deliver a strong headache. In recreational or medicinal cannabis strain, a thick layer of trichomes is the first indication that it may well possess an elevated potency level, but it is certainly not a guarantee. It is also necessary that those glistening gland are filled with potent THC.

A small 25x or stronger pocket microscope works well for getting a closer peek at your trichome development. The goal is to examine the capitate-stalked glandular trichomes for the coloration of the glands heads, which varies between strains and with maturity. Most strains start with clear or slightly amber heads which gradually become cloudy or opaque when THC levels have peaked and are beginning to degrade. Regardless of initial color of secretory cavity, with careful observation you should be able to see a change in coloration as the bud ripens.

Some cultivators wait for about half of the secretory cavities to turn opaque before harvesting, to ensure maximum THC levels in the finished products. Try samples at various stages to see what is the best for the phenotype you are growing. While you may be increasing the total THC level in the bud by allowing half of the glands to go opaque, the buds will also have a larger percentage of THC breakdown products such as CBN, which is why some people choose to harvest earlier while most of secretory cavities are still clear.

Indica varieties will usually have a 10-15 day harvest window to work with. Sativas and Indica/Sativa hybrid often have an extended period to work with.