Aside from set and setting, the main factors in determining the quality and intensity of the high are the amount, and the particular ratio, of cannabinoids present in the material.
THE CANNABINOIDS
There are more than 40 known cannabinoids, but most of these occur in very small amounts and are not important to the high. The cannabinoids found in greatest quantity are THC, THCV, CBN, and CBC.
THC (tetrahydrocannabinol) is the main psychoactive (mind-bending) ingredient in marijuana, and accounts for most of the high. Actually THC is found in four or five variations with slight differences in their chemical structure. The variants have similar effects. THC occurs in all varieties of cannabis, in concentrations that vary from trace amounts to about 95 percent of all the cannabinoids present.
THCV (tetrahydrocannabivarin) is closely related to THC, and has been found in some varieties of Asian and African grass. Colombians have not yet been tested for THCV, but some varieties are likely to contain this substance. THCV seems to be much faster in onset and quicker to dissipate than THC, but its psychoactivity appears to be somewhat less than that of THC. THCV is usually associated with extremely potent grass.
CBD (cannabidiol) also occurs in almost all cannabis varieties in quantities that range from trace amounts to 95 percent of all the cannabinoids present. In its pure form it is not psychoactive, but does have sedative, analgesic, and antibiotic properties. CBD contributes to the high by interacting with THC to potentiate or antagonize certain qualities of the high. It appears to potentiate the depressant effects and to antagonize the euphoric effects. It also delays the onset of the high, but makes it last considerably longer. Terms such as “knockout,” “sleepy,” “dreamlike,” and “contemplative” are often used to describe the high from grass with sizeable proportions of CBD.
CBN (cannabinol) is produced by the degradation of THC. Fresh samples of marijuana contain very little CBN, but curing, poor storage, or processing can cause much of the THC to be oxidized into CBN. When grass is pressed for shipping, the resin glands that hold and protect THC are sometimes ruptured, exposing the cannabinoids to air and increasing the rate of oxidation. CBN in its pure form has at most 10 percent of the psychoactivity of THC. CBN seems to potentiate THC’s disorienting qualities, making one feel more drugged, dizzy, or generally untogether, but not necessarily higher. With a high proportion of CBN, the high may start well and then feel as if it never reaches its peak, and may not last long. Colombian grasses sometimes contain half as much CBN as THC.
CBC (cannabichromine) is inactive in its pure form, but is suspected of potentiating THC. Some tests made for CBD may actually have measured CBC, which is chemically similar.
THE EQUATORIAL THEORY
The ratios of cannabinoids found in different varieties of cannabis differ greatly. Generally, marijuana grown at the equator contains mostly THC, CBN, and THCV, with only traces of CBD. As the distance from the equator increases, the amount of CBD in relation to THC increases. At the 30th parallel (northern Mexico, Morocco, and Afghanistan), amounts of CBD and THC found in adapted varieties are about equal. Above the 30th parallel, cannabis plants are usually considered hemp.
But this is not a hard-and-fast rule. Within any macroclimatic area there are many microclimates, which may show extreme variations in environmental conditions. Since a patch of plants is adapted to the conditions in exactly the area where that patch is located, there may be major differences in the quality of adapted marijuana from several nearby stands. In the American Midwest, the content of CBD in samples of cannabis taken from escaped hemp (plants which had escaped from hemp fields) ranged from trace amounts to 7.1 percent; the THC content, from trace amounts to 2.3 percent. The high THC content indicates that there is potent marijuana growing “wild” in the Midwest. On the other hand, samples of hemp from India and Iran, two countries usually associated with good marijuana, contained (respectively) .11 and .18 percent THC and 2.4 and 1.63 percent CBD.
All this means that over many generations, each population of cannabis adapts to the particular conditions it faces. However, cannabis grown directly from tropical seeds will resemble its parents in growing habits and potency. First-and second-generation descendants will also reach a potency close to that of their tropical ancestors.
Evolutionary theories are predicated on the process of natural selection: that is, the plant that is more fit (for a particular environment) will be more likely to survive and reproduce. Just why the change in THC-CBD ratios occurs is unknown. However, America’s marijuana growers, through selective breeding, have developed high-THC varieties adapted to the temperate environment.
The serious consumer faces two problems: ascertaining where the marijuana comes from, and determining the variety of seeds from which it was grown. Much of the grass now being imported was grown from top-quality seeds given to the grower by the dope exporter. For instance, the quality of Mexican has improved in recent years as Colombian and Southeast Asian seeds have been introduced to the area. Twenty years ago there was virtually no grass grown in Hawaii. Today, almost all of the grass grown there is descended from seeds recently imported to the islands from various sources. This becomes apparent when buds from different Hawaiian growers are compared. They differ in color, shape, size, as well as potency — factors determined in part by genetics.