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The history of 4/20
420 traces to 1971, when five friends at San Rafael High School in California used "4:20" as their code for an after-school meetup to hunt a rumored cannabis crop. The number stuck, spread through Grateful Dead culture, and became the world's cannabis holiday. Almost every other origin story is a myth.
Meet the Waldos
The five friends, Steve Capper, Dave Reddix, Jeffrey Noel, Larry Schwartz, and Mark Gravich, called themselves the Waldos because they hung out by a particular wall on campus. One autumn they got hold of a hand-drawn treasure map: a Coast Guard serviceman who grew cannabis near Point Reyes had supposedly abandoned the crop and passed the map along. The Waldos agreed to meet after school at 4:20 p.m. by the statue of Louis Pasteur and go looking. They never found the stash, but "4:20 Louis," their code for the meetup, got shortened to just "420" and became their private signal for cannabis.
How it went national
One Waldo, Dave Reddix, had connections to the Grateful Dead; his older brother managed a side project for bassist Phil Lesh, and Reddix went on to roadie for the band. That brought "420" into the inner circle of one of the most influential touring acts in America, and the Dead's wandering, cannabis-friendly fan culture carried the slang from California to concert lots across the country through the 1980s.
In December 1990, Deadheads in Oakland handed out a flyer inviting people to smoke "420" on April 20th at 4:20 p.m. A copy reached High Times magazine, where editor Steven Hager championed April 20th as an unofficial cannabis holiday in print through the early 1990s. With the magazine's reach in counterculture circles, the term spread onto bumper stickers, song lyrics, and T-shirts everywhere. In 2003 California passed Senate Bill 420, regulating medical cannabis under the Compassionate Use Act; whether the bill number was deliberate has never been confirmed, but it cemented 420 in cannabis law and lore.
Clearing up the myths
420 is one of the most myth-plagued numbers in pop culture. A few of the most persistent, put to rest:
| The myth | The truth |
|---|---|
| "420 is a California police code for cannabis." | There is no such code. It does not exist in California’s penal code or any law-enforcement radio system. |
| "It comes from Bob Dylan’s Rainy Day Women #12 & 35." | The math works (12 x 35 = 420), but there is zero evidence Dylan chose those numbers for that reason. A coincidence, not the origin. |
| "420 is the number of active chemicals in cannabis." | Scientists have identified over 500 compounds in the plant. The number 420 has no special chemical significance. |
| "April 20th is Bob Marley’s birthday." | Marley was born on February 6th. His legacy is enormous, but he is not the source of this one. |
The documented origin, the Waldos, the treasure map, and the Grateful Dead, is backed by physical evidence, including original letters and a "420" flag the Waldos saved from 1971. The story is real; the rest are just stories.
What 4/20 means now
For a lot of people, April 20th has grown into something bigger than its origin: a moment to recognize how far cannabis has come, and how far it still has to go. We think of it as a reminder of why education matters, because the more anyone understands about the plant, its history, its compounds, and how it works in the body, the better equipped they are to make informed choices. So here is to the five kids from Marin County who unknowingly gave the world a reason to show up at 4:20.
Educational and cultural content, not medical advice. Cannabis laws vary by state. For adults 21 and older where adult-use is legal, or qualified patients where medical-only. Keep cannabis out of reach of children and pets.