The magic 0.3 percent figure is thrown around quite often, but what does it actually mean? And why 0.3 percent? In the US, this figure represents the dry weight of THC in any cannabis crop. If it contains more, the crop is considered marijuana. If it contains less, the harvest is hemp. Europeans have it even more difficult, as in the majority of Europe, the legal limit is 0.2 percent. But who decided on these limits to begin with?
The 0.3 percent figure actually stems from a 1976 report authored by two Canadian plant scientists—Arthur Cronquist and Ernest Small. It’s doubtful that they could have imagined their research would become the basis of the legal limit separating criminal activity from non-criminal activity, but there you have it.
Their report, titled A Practical and Natural Taxonomy for Cannabis was essentially a study of the characteristics of the plant. In the paper, the researchers defined cannabis sativa as containing less than 0.3 percent THC by dry weight and plants containing more were classified as Cannabis indica.
The document briefly mentioned that sativa had only a limited ability to be intoxicating while indica was more likely to produce mind-altering effects. However, the purpose of the research was not intended to establish a person’s level of intoxication while using the plant. It was simply a study of the plant itself.
Nevertheless, the Canadian government used the material in the paper to create legislation, and the US soon followed suit. And that is where the arbitrary 0.3 percent number originated.
Although it lacks scientific credibility and is even a bit silly, the line of demarcation established with that number is what legally separates CBD from THC. Up until a few years ago, there was no such separation. The 2018 Farm bill established a long-awaited green light for hemp farmers to move forward and CBD was decriminalized.
For what it’s worth, that capricious number is what allows us, for now, to use CBD without fear of prosecution.