The feds began monitoring the potency of the nation’s pot supply in the ‘70s by drawing samples from stashes seized by law enforcement, and boy was it schwag. The percentage of THC—the main psychoactive component in cannabis—averaged from less than 1% in 1975 to just under 3% a decade later, according to the data.
These notoriously low levels reflected the times, as the weed subculture in America was just starting to take root and could help explain why some of the most memorable old school brands have names like Acapulco Gold, Panama Red, Afghani, Thai stick, and Jamaican sensi; they were all originally cultivated outside of the country.
Now, as some critics have pointed out, it’s impossible to empirically confirm how strong domestically grown pot was back in the day due to inferior testing and sampling methods, however, there does seem to be enough prevailing research, firsthand testimony, and common sense to show that the illicit reefer from decades ago wasn’t nearly as powerful as today’s. Even if we account for the inordinate amount of Mexican brick weed that’s said to have dragged down national averages, the percentage of THC was still remarkably low across the boards well into the late 1990’s.
A recent federal study found that “the potency of illicit cannabis plant material has consistently risen over time since 1995 from approximately 4% in 1995 to approximately 12% in 2014.” This marked increase represents a shift when smokers began to pivot from dirt to mid-grade and hydro.
In one standout bust from 2009, the DEA nabbed some sticky-icky that scored an impressive 33.12%, the highest concentration of THC the agency has ever seen in a domestic sample of weed. Keep in mind, the government stats don’t include samples from the “legal” market, where flowers—a common euphemism for buds—have tested way above 20% and even upper 30%, with cannabis concentrates soaring into the 90% range, a remarkable achievement in human history. Generally speaking, anything over 15% is considered good shit.
There’s also the less scientific method of examining photos of buds from early issues of High Times, since you can also tell a lot about cannabis from how it looks. The visual evidence suggests that the “grass” in the free love era—including the stuff Bob Marley smoked—lacked the characteristics associated with the quality found in today’s headier brands like Girl Scout Cookies, Bruce Banner, and Gorilla Glue.
Many of the nostalgic strains didn’t have large concentrations of trichomes, the crystal-like resin glands that are very identifiable in photos and which have come to define modern day chronic. The old school buds were also stringy and brown. By all accounts, it looked inferior, because it was.
This week on Giz Asks, we asked the DEA, weed dispensaries, cannabis cultivators and an esteemed professor who has been growing weed for the federal government for the past few decades, why cannabis is getting so potent.
Mahmoud A. ElSohly, Ph.D.
Professor of Pharmaceutics in the School of Pharmacy at the University of Mississippi, Director of the Marijuana Project at the University of Mississippi. For the past few decades, he has been growing weed for the federal government at the only legally-permitted weed farm on the Ole Miss campus.
The answer to your question in my opinion lies in several facts:
1) The cultivation practices in the cannabis industry has moved into the production of sinsemilla as the preferred product. Sinsemilla is the product generated from the flowering tops of female plants that have not been fertilized. It is the part of cannabis plant with the highest THC content.
2) The trimming of the cannabis products (sinsemilla or buds) and removal of all large leaves which have low levels of THC.
3) Selection of high THC varieties or strains for high cash value.
4) THC is known to produce tolerance in frequent users. Therefore the more one uses marijuana the more THC one needs to achieve the same degree of high one once had. So the users demand more marijuana or higher THC content.
CEO of Terra Tech California-based, publicly traded cannabis company (TRTC) that grows, markets and retails cannabis
Over the last decade, potencies in cannabis have risen sharply because of the adaptation of the plant sciences that have migrated from traditional agriculture into the cannabis scene. A major driver in the increased presence of cannabinoids is primarily due to better breeding, strain-crossing as well as tissue culturing. However the plant’s genetic makeup is just one component. In addition, we’ve seen an increase in scientific and data based plant cultivation techniques. Essentially, the combination of better genetics coupled with more advanced cultivation techniques have led to a higher quality end product. We believe this trend will continue over the coming years.
Spokesperson for Marijuana Policy Project, an influential lobby group focusing on reforming federal law so states can decide legalization
Marijuana has gotten more potent over the last few decades for several reasons. The first is prohibition. By breeding marijuana to be more potent, less must be consumed to achieve the desired results, which means that there is less to grow, transport, or hide illegally. The same thing happened during alcohol prohibition. Hard liquors became much more popular because it was easier to move and hide from authorities.
Another reason is customer demand and safety. The more potent marijuana is, the less people have to smoke, which is easier on the lungs. The popularization of vaporizing marijuana also creates more demand for higher potency since this process works better with higher-density cannabinoids.
The increase in patients using marijuana for medical purposes has also driven a huge increase in THC and other compounds through selective breeding and the development of concentrates. Many patients need instant, powerful pain relief that is much harder for them to achieve with low-potency marijuana.