Potency of Marijuana Plants and Plant Parts

Previously, we’ve noted that different types (and even different plants) of the same variety can vary in potency. Generally, domestic marijuana contains a greater concentration of THC than Mexican variations which are usually grown outside and not for use as sinsemilla. Since the early 1990s, higher-quality Canadian “BC Bud,” comprised of indoor-grown sinsemilla, has been imported in large amounts.

Environmental factors play a role in determining the bud’s potency. Weather, growing conditions, and quality of care all affect the characteristics of marijuana just like they would with flowers and vegetables.

Different portions, different potencies

Different portions of cannabis different potencies

Different portions of the actual marijuana plant have different potencies. THC is, for the most part, found in glands that grow on the surface of the plant’s stem and leaves. These resin-excreting glands called trichomes resemble tiny mushrooms when under a microscope. The trichomes are largely concentrated on the miniscule leaves and stems surrounding and inside the female flower clusters. More sizable leaves from this area are generally picked off (manicured) after the buds have been harvested. These leaves, known as trim, contain less THC than the smaller leaves and organs in the immediate vicinity of the flower. The large fan or sun leaves have an even smaller amount of glands and are remarkably less potent than the flowers or the trim.

Drug opponents have tried to frighten the public with tales of the supposed dangers of more potent marijuana. Of course, they neglect to mention the advantages of higher-potency marijuana for reducing smoke inhalation. Federal officials have charged that marijuana’s potency in certain strains has increased so much that it should be classified as an entirely new drug. In reality, potencies haven’t changed for some time, and high potency preparations like hashish, hash oil, special strains, and extracts have been around since at least the 19th century. Marijuana’s average potency has seen a slight increase due to the rising popularity of high-quality indoor sinsemilla.

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High-potency formulations have a long history of medical use. Indeed, until the 1930s cannabis had been available over the counter in many pharmacies throughout the United States and was sold in alcohol-based tinctures at 25% potency. Doses were usually measured in drops.

Medical users often prefer to use high-potency sinsemilla and concentrated preparations to protect themselves from harmful smoke. In cases where inhalation isn’t necessary, oral ingestion is much better.

Concentrating THC

Concentrating THC

Sinsemilla is from the Spanish for sin, “without” and semilla, “seed.” These marijuana buds can go for up to hundreds of dollars per ounce—potentially several thousand dollars per pound—and can usually have between 4% and 20% THC concentration. Large fan leaves have about a 2 to 3% THC concentration and usually sell for only $100 to $300 per pound.

Trim leaves contain around 2 to 3% THC and sell for around $200 to $500 per pound. The leaves and trim are better for frugal-minded buyers, but they tend to be harsh on the throat and unpleasant to smoke.

To solve this dilemma, you can concentrate the THC so that only the potent glands are used. You can do this in several different ways.


Screening cannabis

Silkscreens are the easiest to use, but steel or plastic mesh screen with 100 or 125 lines to the inch can be better. The spaces in the screen allow the glands to drop through while the vegetable material stays on top. The yield is dependent on the quality of the material you started with. You can find suitable framed screens at marijuana dispensaries or through the Internet.

To use a screen, you need to first dry the marijuana by placing it in a microwave oven. When the marijuana crumbles or snaps in hand, it is dry enough to screen. It does not need to be broken up. Next, place the dried marijuana in a freezer until it is entirely chilled. This process makes it simpler to remove the glands.

If you’re using a silkscreen or other line cloth screen, be sure to stretch it tight over a collection vessel (e.g. a bowl). Framed screens can just be placed over a table or tray. Rub the dried, chilled material over the screen. More glands will fall through depending on how long the material is rubbed. Note, however, that rubbing the material longer will also increase the amount of plant debris that makes it through the screen. The process is quite similar to olive pressing in that longer presses decrease the quality of the oil because more impurities are squashed out.

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Concentrating cannabis by screening often requires a little finesse and experience. If you have an end use in mind, then you’ll know when to stop screening. The initial screening produces the best “kief” (un-pressed hashish). Glands that slip through the screen can be smoked in a pipe, added to a joint, or simply ingested. Their extreme potency ensures that only small amounts are needed. Too much plant debris can make smoking cannabis less desirable, but the additional vegetative matter isn’t as important when eaten. For smoking, try to achieve the purest resin. For consumption, try to produce a larger yield for whatever the concentration happens to be.

Water screening

Water screening cannabis

THC glands are heavier than water and will sink when placed in it. Nearly all vegetative material is lighter and tends to float. This makes it rather simple to distinguish between the usable glands and the vegetative material. The subsequent kief is rather clean and very concentrated. The plant can be screened mechanically prior to water screening, but it doesn’t really have to be. Any pollutants, molds, and fungi are rinsed away in the “wash.”

To screen with water, put whole marijuana in a jar along with cold water and a few ice cubes. Then, just shake the mix for a minute or two. The lighter vegetative material is scooped out and the heavier glands fall to the bottom. These are taken out of the jar and dried.

Do not use warm or even tepid water because the glands will become soft and sticky, making them much harder to work with. In ice-cold water, the glands remain rigid and brittle.

As these glands are rather powerful, you’ll only need a pinch in a pipe bowl for relief. They can also be swallowed in capsules or eaten in food.

One medicinal user cooks with the THC-bearing glands. She maintains a small container of the substance and utilizes a tiny spoon to add it to the food.

Thanks for reading and if you want to start growing, download my free marijuana grow bible and order some marijuana seeds. All top quality marijuana seeds are available in my marijuana seed shop. We ship seeds to the US, CA and many other countries. For any grow related question please visit the marijuana support page.


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Robert Bergman

Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations. His passion for growing led him to develop his own Gold Leaf strain. Now, Robert is dedicated to sharing his knowledge with the world.... [Read full bio]


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