Hempirical Evidence is the research journal of Nick Johnson, historian, editor, and author of the book Grass Roots: A History of Cannabis in the American West (Oregon State University Press, 2017).

My work is also featured in the following publications/websites:

Agricultural History
The Cannabist (Denver Post)
Colorado Encyclopedia
Colorado Heritage
Erstwhile (University of Colorado-Boulder)
Points (Alcohol & Drugs History Society)
Process (Organization of American Historians)
Public Lands History Center (Colorado State University)

On this blog you'll find short essays based on my ongoing research, book reviews, and commentary on current cannabis-related issues and events. The purpose of this blog is simply to present research and thoughtful opinions with the hope of encouraging intelligent, honest, and productive dialogue about cannabis and its place in world history and society.


In the fall of 2012, I came to Fort Collins, Colorado to get my MA in history at Colorado State University. That November, I witnessed the passage of Amendment 64, the ballot initiative that legalized the adult use of cannabis in Colorado. I was looking for something to write about for my master's thesis, and soon found that behind this momentous change in drug policy was a millennia-old relationship between a useful plant and its human propagators.

I brought my training in environmental history to bear on the cannabis story and completed my master's thesis, "Rocky Mountain High," in the spring of 2014. I argued that studying cannabis as a plant as well as a drug can allow us to better understand its various roles in American culture and society.

Grass Roots is a further exploration of the plant's historical and current impact on American society. The book examines cannabis's past through an agricultural lens in order to explain, critically engage, and offer possible solutions to the environmental and social challenges associated with the rise of America's newest legitimate cash crop.


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