The History of 420: How a High School Code Became Cannabis Culture [2026]

This guide to 420 history covers the background, key facts and related seeds from the Seeds Here Now catalog, for adults 21+.

Every April 20th, millions of cannabis enthusiasts worldwide celebrate 420—the unofficial holiday of weed culture. But most people who light up at 4:20 p.m. or attend a 420 rally have no idea where the tradition actually started. It wasn’t a police code. It wasn’t a Grateful Dead song. It was five teenagers in San Rafael, California, a treasure map, and a statue of Louis Pasteur.

The Origin of 420: The Waldos

In the fall of 1971, five students at San Rafael High School in Marin County, California, heard about an abandoned cannabis crop planted by a Coast Guard service member who could no longer tend it. The students—Steve Capper, Dave Reddix, Jeffrey Noel, Larry Schwartz, and Mark Gravitch—called themselves “the Waldos” because they hung out by a wall outside the school.

The Waldos agreed to meet at 4:20 p.m. by the Louis Pasteur statue on campus, pile into a car, and drive out to Point Reyes to search for the legendary free crop. They never found the plants.

“420 Louis” eventually shortened to just “420.” And the Waldos used it constantly—before school, after school, during school. It was their signal. Their culture. Their thing.

How 420 Spread: The Grateful Dead Connection

Here’s where the story gets interesting. The Waldos had direct connections to the Grateful Dead’s inner circle. Dave Reddix’s older brother was close friends with Dead bassist Phil Lesh, and Mark Gravitch’s father managed Dead real estate. The Waldos spent time backstage at Dead shows, and their “420” code spread through the band’s extended family of roadies, crew members, and the Deadhead community.

From there, it went viral—1970s viral, meaning it traveled through concert lots, crash pads, and word of mouth across the counterculture network that followed the Dead around the country. By the late ’70s, “420” was embedded in the vocabulary of cannabis culture nationwide, even though most people using it had never heard of the Waldos.

High Times and the Mainstream

A reporter from High Times magazine got hold of the flyer, and the magazine began using “420” regularly in articles and references.

High Times went on to popularize April 20th as an annual cannabis celebration, and by the late 1990s, 420 was everywhere—on bumper stickers, T-shirts, rolling papers, and eventually in mainstream media. The number became the universal code for cannabis, recognized around the world.

Common 420 Origin Myths (Debunked)

Over the decades, several false origin stories have circulated. Let’s clear them up:

• “420 is a police code for marijuana.” No. California Penal Code 420 deals with obstructing entry to public land. The number has no law enforcement connection to cannabis.
• “There are 420 chemical compounds in marijuana.” Not accurate. Cannabis contains over 500 identified compounds, including more than 100 cannabinoids. The number doesn’t match.
• “April 20th is Bob Marley’s birthday.” Bob Marley was born on February 6, 1945. He died on May 11, 1981. Neither date is 420.
• “It started with a Grateful Dead song.” The Dead didn’t create 420, but their community was the vehicle through which it spread from five kids in Marin County to the world.

420 today

What started as a teenage treasure hunt code has evolved into something much bigger. April 20th is now a day of celebration, activism, and industry significance:

Cannabis Rallies and Events

Major cities host 420 events drawing tens of thousands. Denver’s Mile High 420 Festival, San Francisco’s Hippie Hill gathering, and events across Canada, the Netherlands, and beyond have turned the date into a global celebration of cannabis culture and legalization progress.

Industry and Retail

For cannabis businesses, 420 is essentially Black Friday. Dispensaries, seed banks, and accessories companies run their biggest sales of the year. At Seeds Here Now, we go hard every April with drops, deals, and limited genetics that collectors and growers wait all year for.

Political Activism

420 has been a rallying point for legalization movements worldwide. The visibility of mass gatherings on April 20th has helped normalize cannabis use and push legislative reform forward in states across the U.S. and countries around the globe.

Celebrate 420 the Grower’s Way

The best way to honor the spirit of 420? Grow something. The Waldos weren’t buying pre-rolls from a dispensary—they were searching for free plants in the hills of Northern California. That DIY, grow-your-own mentality is the actual root of cannabis culture.

If you’ve been thinking about starting a garden, April is prime planting season. Grab some feminized seeds, some autoflowers for a quick summer harvest, or go old-school with regular seeds and do some breeding. Whatever you grow, you’re carrying on a tradition that started with five kids, a map, and a meeting time of 4:20.

Shop 420 deals and the latest genetics at Seeds Here Now. We’ve been serving growers since 2010—and every April, we make sure 420 hits different.

How to Read a Seed Pack Label

Most breeder labels show the strain name, the breeder, the seed type and the seed count. Feminized and autoflower packs are marked as such, and regular packs contain a natural mix of male and female seeds. Many labels also print the cross, for example “Parent A x Parent B”, plus a filial marker such as F1, F2, S1 or BX.

F1 is a first-generation cross of two distinct parents, S1 is a line made from a single parent and BX is a cross back to one of the original parents. These details tell you far more about a pack than its name alone.

Frequently Asked Questions

What does 420 mean?

420 is a slang term for cannabis and cannabis culture. It originated in 1971 with a group of high school students in San Rafael, California, who used “420” as a code for meeting at 4:20 p.m. to search for an abandoned cannabis crop. The term spread through the Grateful Dead community and eventually became a worldwide symbol of cannabis culture.

Why is April 20th a cannabis holiday?

April 20th (4/20) became the unofficial cannabis holiday because of the connection between the number 420 and cannabis culture. High Times magazine popularized the date as an annual celebration in the 1990s, and it has since become a global event featuring rallies, sales, and community gatherings.

Is 420 a police code for marijuana?

No. This is a common myth. The number 420 has no connection to law enforcement codes related to marijuana. California Penal Code 420 deals with obstructing entry to public land, not cannabis. The real origin traces back to five high school students in 1971.

Who were the Waldos?

The Waldos were five students at San Rafael High School in Marin County, California: Steve Capper, Dave Reddix, Jeffrey Noel, Larry Schwartz, and Mark Gravitch. They coined the term “420” in 1971 as code for their after-school cannabis treasure hunts. Their connection to the Grateful Dead’s inner circle helped spread the term nationwide.

420 history: Quick Answers

How do I choose between feminized, regular and autoflower seeds?

Feminized seeds keep things simple, regular seeds suit anyone making their own crosses, and autoflowers suit short seasons and quick runs.

How should I store seeds?

Keep them sealed in the original pack inside an airtight container with a desiccant packet, somewhere cool, dark and steady.

Further reading: Wikipedia: Cannabis strain.