Hi Guys, thought I'd share this with you all. I found it a very good read and clears up some questions regarding trichome ripeness/readiness. Credit goes to CC Magazine and & Mr Bloom @ THC. Hopefully it may help someone else;
If you’ve seen pictures of mature cannabis plants taken with a macroscopic lens that’s zoomed-in very close, then you’ve undoubtedly noticed the many glistening translucent resin glands protruding from the buds, leaves, and just about everywhere else on the plant. Most marijuana growers and readers of pot magazines are quite familiar – and some downright obsessed – with these resinous outgrowths known as trichomes. You may have also read that the sticky coating of trichomes is home to the active ingredients in cannabis – the stuff that gets you high and has all the medical benefits – tetrahydrocannabinol (THC), cannabidiol (CBD), and other cannabinoids. But have you ever wondered exactly what the trichomes do for the cannabis plant, or what biological purpose they serve?
Evolution of Trichomes
In nature, only the strong survive, and it is hypothesized by biologists that trichomes evolved as a defense mechanism of the cannabis plant against a range of potential enemies (1). Trichomes, from the Greek meaning ‘growth of hair,’ act as an evolutionary shield, protecting the plant and its seeds from the dangers of its environment, allowing it to reproduce. These adhesive sprouts form a protective layer against offensive insects, preventing them from reaching the surface of the plant. The chemicals in the trichomes make cannabis less palatable to hungry animals and can inhibit the growth of some types of fungus. The resin also helps to insulate the plant from high wind and low humidity, and acts as a natural ‘sun-screen’ in protecting against UV-B light rays. But since trichomes contain euphoric properties attractive to humans, it may be man who has had the most influence on the plants’ development through many years of favoring strains that consistently produce more of these gooey resin heads.
Trichomes grow in numerous shapes and sizes on many types of plants. The cannabis plant has developed three main types (from NationMaster Encyclopedia):
Bulbous: This type is the smallest (15 to 30 micrometers). From 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, presumably cannabinoids, and related compounds that accumulate between the head cells and the cuticle. When the gland matures, a nipple-like protrusion may form on the membrane from the pressure of accumulating resin. The bulbous glands are found scattered about the surfaces of the aboveground plant parts. [Pictured below.]
Capitate-Sessile: The second type of gland is larger (25 to 100 micrometers) and more numerous than the bulbous glands. They are called capitate, which means having a globular-shaped head. On immature plants, the heads lie flush, appearing not to have a stalk and are called capitate sessile. They have a stalk that is one cell high, although it may not be visible beneath the globular head. The head is composed of usually eight, but up to 16 cells, that form a convex rosette. These cells secrete cannabinoids and related compounds that accumulate between the rosette and its outer membrane. This gives it a spherical shape.
Capitate-Stalked: Cannabinoids are most abundant in the capitate-stalked glands, which consists of a tier of secretory disc cells subtending a large non-cellular secretory cavity. During flowering, the capitate glands that appear on the newly formed plant parts take on a third form. Some of the glands are raised to a height of 150 to 500 micrometres when their stalks elongate. These capitate-stalked glands appear during flowering and form their densest cover on the female flower bracts [specialized leaves that cover the seeds]. They are also highly concentrated on the small leaves that accompany the flowers. The male flowers have some stalked glands, but they are smaller and less concentrated than on the female. (2)
Cannabinoids are a group of chemical compounds that occur naturally in the cannabis plant, first discovered in the 1940s. When consumed by humans, the chemicals bind to CB1 and CB2 cannabinoid receptors in the brain and body, causing euphoria and other effects. The broader definition includes three general types: phytocannabinoids, which occur uniquely in the cannabis plant; endogenous cannabinoids, produced by the bodies of humans and other mammals, birds, fish, and reptiles; and synthetic cannabinoids, which are related compounds produced in laboratories. Cannabinoids present in the cannabis plant include THC, CBD, cannabinol (CBN), cannabichromene (CBC), cannabigerol (CBG), and tetrahydrocannabivarin (THCV).
Inside the Trichome
THC and other cannabinoids are produced in only one place on the cannabis plant: inside the heads of the trichomes. How it happens: Organelles produced by the plant called Vacuoles – which contain phenols, a chemical compound similar to alcohol [pictured at right in blue], and another type of organelle called plastids – containing hydrocarbons called terpenes [red], make their way up the trichome stalk [green] and combine inside the secretory cavity into a fibrous mat [yellow]. This concentrated mat is hit by UV-B light waves, causing the creation of cannabinoids. Since all of the psychoactive ingredients are produced inside the trichome, these tiny resin hairs have long been sought after by hash and oil makers and can be separated from the plant and harvested in a variety of ways (3).
Potency and Tricomes
Many media outlets and politicians say the ‘potency’ of today’s pot has increased dramatically in the last 30 years, claiming it contains anywhere from 10%-40% THC. Most are dubious claims, as it is quite obvious that a sample of herbal plant material does not consist of nearly half THC, but there is still much debate on the issue of potency classification. One thing is for sure; heavy trichome production does not necessarily mean higher potency, because the resins inside the trichome may or may not contain high levels of THC and other active ingredients. Some speculate that the percentage levels refer to the amount of THC in the oils produced inside the resin glands, but new studies show that cannabinoids other than THC also have distinctive effects on brain functions and cause correspondingly different effects on human cognition and psychiatric symptoms (4). This makes gauging the ‘potency’ or ‘strength’ of cannabis plants very difficult, as different cannabinoid level combinations may induce different types of highs.
There are many ways to separate the trichomes from the plant to make hash, oil and butters, or to smoke directly as dry-sifted kief. Fine mesh screens and products like BubbleBags assist in the extraction process. When it comes to dry-sifted trichomes, it is very difficult to completely separate the resin heads from the stalk and other waste product of the plant.
So you have worked hard for 8 weeks! You have invested money into equipment and possibly genetics; you have invested time and dedication to get to this point. How can you tell when it’s time to harvest your gooey girls? Well 'fire one up' and let’s take a look at the best way to be sure you’re harvesting at peak potency. This article will help you understand what happens in the final weeks, so you can harvest for the specific type of high you prefer.
The harvest window is one aspect of the craft which, unfortunately, gets overlooked. As well, many growers simply don’t have the patience to wait-out the last few days to insure max THC content.
Some strains are better harvested before their peak THC production and some are better harvested after their peak THC production.
Robert Clark wrote about trichomes and what they tell us in his book “Marijuana Botany”;
“The elevated resin heads appear clear, since fresh resin is still being secreted, often being produced in the cellular head of the trichome. At this time THC acid production is at a peak and CBD acid levels remain stable as the molecules are rapidly converted to THC acids, THC acid synthesis has not been active long enough for a high level of CBN acid to build up from the degradation of THC acid by light and heat. Terpene production is also nearing a peak and the floral clusters are beautifully aromatic. Many cultivators prefer to pick some of their strains during this stage in order to produce marijuana with a clear, cerebral, psychoactive effect It is believed that, in peak floral clusters, the low levels of CBD and CBN allow the high level of THC to act without their sedative effects.”
What the hell does this mean?
When growing Indica hybrids, unless you want to end up on the couch, it’s best to harvest when the trichome heads are fully formed but before they start to cloud over and turn amber. This could take as little as five days or as long as two weeks, depending on the maturation time of the specific strain. If you allow an Indica to go too long, you can dramatically affect the taste and high. Fortunately, going too long is not a real problem for most people.
I like to study close-up photos taken with a high resolution digital camera; however an inexpensive hand-held microscope works wonders. It almost looks like you are in an alien world when looking at resonated buds using fifty-times-power.
With the Sativa-dominant hybrids, you want to make sure that all the trichome heads are fully formed and also about thirty percent amber. Letting a plant mature beyond this point will risk flavor and the finished smoke may be harsh with very little "high". There are exceptions; Haze has three different harvest windows, all being very late into flower. It is every grower’s job to learn what he or his patients prefer in the terms of "high".
This article will not address yields: if you are at the third stage of floral maturity with fully-formed trichomes, we can assume most strains have packed on all their final weight.
Use the guidelines spelled out below to help gauge the best harvest window for your plants based on the trichomes.
1. Fully-formed but still clear will provide a cleaner 'up' high with less sedative effect; this is the best window for heavy Indicas.
2. Fully-formed and turning slightly cloudy or milky; this is probably the best time to pick most hybrids available today.
3. Fully formed completely cloudy or milky with at least 30% of the heads turning amber; this is usually best window for the late maturing Sativa’s such as Haze. This is also a good window when using the plant primarily for Hash production.
Take for instance the Jacks Cleaner, harvested at 56 days; all trichomes are still visibly clear with very few turning cloudy. At this point it has a very 'up' high and an 'in-the-head' buzz. I get some good visuals and the lemon flavor is sour and a tad tart.
The same plant, left just one more week at 63 days flower; the trichomes have turned milky white and a good portion, about 30-50%, are deep amber - almost the color of cola. Taken at this time, the smoke is heavy and thick, the lemon zing has been replaced with a musty sweet lemon smell that reminds me of ‘Lemon Heads’ candy. The high is now all body high and very much a sedative. We would smoke this only as our nighttime medication. It is almost an example of a plant taken too late; however, we do this because of the medicinal properties she takes-on at this late stage.
Another example is Killer Queen. At 49 days flower, she has a candy-like smell and taste with that same 'up' high. If you were to harvest her at 60 days flower, she becomes 'Super' Killer Queen, with a more skunk-like smell and a thicker trance-like high.
The mistake to avoid is harvesting before the trichomes are fully formed; most growers who use this method harvest when the majority of the heads are cloudy. Harvesting before this window will produce bud that is less potent, containing less essential oils and trepans, causing your finished stash to take on a grassy or green taste, even if it is dried and cured correctly.
Another good method would be harvesting some of the more mature buds, usually being the upper or main colas. This will allow more light to shine down on the lower portion of the plant, not only will the buds mature further but they will also pack on some extra size.
If you have a nice digital camera with a macro feature, try taking some close-up photos and use a photo editing program such as Adobe. This will allow you to zoom in close so you can see what the naked eye cannot see. If this is not an option, Radio Shack and other electronic stores sell battery-powered hand-held microscopes for about $15.
Take advantage of this information, it will help maximize the results of your favorite strain, or help you determine the harvest window of something new.
Edited by FatBagZ, 17 August 2016 - 10:19 AM.