According to annual reports from the National Institute on Drug Abuse, the potency of confiscated marijuana has consistently increased over the past few decades. Until 1978, weed tested at an average of less than one percent THC. Today, that kind of weed wouldn’t even get you high. Since then, growing techniques and testing methods have evolved—leading to an increase in potency.

Has Weed Gotten Stronger?

If we’re measuring potency by the level of THC, weed is getting stronger over time.

Weed subculture only began to blow up in the 1970s. Back then, all popular buds were uncrossed landrace strains, usually named after the area of origin. For example, strain names like Colombian Gold and Thai Sticks hinted at where the bud originated from. Nowadays, a lot of the cannabis in the United States is grown domestically.

If you took a look at a High Times magazine from the ’70s, you’d think our top 40 buds looked like trash by today’s standards. Back then, bud was dark green or brown in color, leafy, thinner and there were lots of visible stems. If they look lower quality than what you’re used to, it’s because they were.

Nowadays, the “top” strains are dense, dank buds covered in shiny crystal-like trichomes.

Putting looks aside, the test results agree that weed is getting stronger than it once was. According to data from recent High Times Cannabis Cups, flower entries are consistently testing at around 30 percent THC.

The DEA didn’t see weed like that until around 2009, when they scored a 33 percent THC crop during a drug bust. Since then, THC levels haven’t gotten much higher—unless you count cannabis concentrates which can test at over 90 percent cannabinoids.

What Made Weed This Strong?

One of the reasons weed is getting stronger is because the cannabis industry has shifted focus on the production of sinsemilla. Sinsemilla is the tops of female plants that have not been fertilized, which contain the highest levels of THC. Harvesters cut off trimmings and remove all large leaves that contain lower levels of THC.

All of the above are likely responsible for weed getting stronger.

Strain selection has also contributed to the increase in potency. Strains with high levels of cannabinoids are favored by growers. Unlike the landrace strains that dominated the ’60s to the ’80s, today’s strongest strains are hybrid crosses of other popular strains. New, more potent combinations are being discovered every day.

Thirty years ago, you’d be lucky to find anything with over 10 percent THC. Now, most “top-shelf” strains are 20 percent or higher. We’ve come a long way from smoking schwag with low levels of THC.

Now that growers have gotten THC levels high enough, the focus lately has been on terpenes and other cannabinoids.

According to the entourage effect, when THC works together with other cannabinoids and terpenes, new medical benefits arise. As a result, a well-balanced flower can end up feeling more potent than one with a high-THC content alone. So now, potency is being measured by a full spectrum of terpenes and cannabinoids—rather than just the THC content.