Now that it’s legal, many who may have once dabbled in their younger years are giving cannabis another try.

And the issue of marijuana potency suddenly becomes very relevant. Stories of baby boomers completely floored by an edible or waxing nostalgic over the less potent, more socially enjoyable weed of days gone by are increasingly common amusing signs of how much things have changed in the last decades.

Or have they?

Evolution of the Cannabis Grow Op

While “back in the day,” plenty of growers were sophisticated, however, the sophistication of the equipment (and available resources) was a very different story.

Between the 1960s and now we’ve had 50+ years of selective breeding for higher and higher marijuana potency. We also have computer controlled light and AC systems, high-tech hydroponics, advanced chemical soil analyses, an astounding array of plant supplements. And, of course, access to a vast array of technical information undreamt of back then – there are now entire magazines dedicated just to growing marijuana.

Times have certainly changed.

The Infamous Police Study

One study that received a tremendous amount of publicity in the weed world looked at confiscated samples of cannabis taken over the last 20 years. In all, they tested over 38,600 samples between the years 1995 and 2015.

Analysis of these samples found that average THC rose from 4% in ‘95 to over 12% in 2015. CBD fell from 0.28% to 0.15%, a shift in the THC:CBD ratio from 14X to 80X in those years. The ratios of different cannabinoids can have a pronounced effect on the perceived potency

If you do a quick survey of marijuana potency in any given rec shop now and most strains will be somewhere close to 20%, some high potency strains pushing upwards of 30% THC.

Not The Full Story

These statistics, however, give something of a false impression.

Was weed in 1995 really only 4% THC? That seems pretty low!

When we dig into the methodology of the study, like this article in the Atlantic, we find the story is somewhat different. THC, for example, degrades over time, turning into another cannabinoid known as CBN. Any measure of THC from a 20 year old sample of marijuana will show artificially low levels of THC from this natural decay.

Further complicating their numbers are the means with which they measured THC, a technique known as gas chromatography. This also alters THC and again leads to artificially low readings.

Digging a little deeper, we find that some years they only analyzed three samples to find an average, and other years they used over 1000 samples, a degree of sample variance that would raise the eyebrow of any scientist.

What Can We Really Say?

While the study’s numbers may be somewhat faulty, it’s still pretty safe to say the marijuana of today’s industrialized and streamlined grow operations is definitely stronger.

But, also keep in mind a couple of important points:

  • Before the legalization of medical marijuana, most cannabis consumed in the U.S. was smuggled stateside from countries like Colombia and Mexico. Most of this bud was what we consider “dirt weed” (a hodgepodge of stems, flowers, leaves and other parts of the plant). It may have been lower in potency, but it was also totally unregulated and of poor quality (often infested with pesticides).
  • Most of today’s cannabis undergoes lab testing and is subject to regulation. So while the potency of yesteryear’s pot may have been lower back then, arguably so was its safety.

Nonetheless, how much stronger is today’s cannabis?

That we may never know, so to anyone out there looking to have another dance with Mary Jane, take it slow and start small. But, we can thank the ganja gods that gone are the days of low quality, unregulated “schwag!”