How the Grateful Dead Spread "420" Across America

Last verified: April 2026

The Bridge Between a High School Code and a Global Word

The Waldos invented “420” in the fall of 1971. By 1991, High Times was publishing it for a national audience. The twenty-year bridge between those two dates is, almost entirely, the Grateful Dead. The connection wasn’t a coincidence. It was built into the Waldos’ own lives from the start.

Two Direct Links to the Band

The Waldos weren’t random fans who happened to like the Dead. They were kids in Marin County in the early 1970s, and the Dead lived in Marin County in the early 1970s. Two of the Waldos had direct personal connections to the band:

• Dave Reddix’s older brother was friends with Phil Lesh, the Grateful Dead’s bassist and a founding member of the band. Reddix’s brother managed some of Lesh’s side projects in the mid-1970s. That gave Waldo Dave direct social access to Lesh and, by extension, the rest of the band’s inner circle.
• Mark Gravitch’s father was a Bay Area real estate agent who sold houses to three members of the Grateful Dead. That professional relationship brought the Gravitch family into regular social contact with the band.

The Waldos were not outsiders trying to penetrate a famous scene. They were teenagers who happened to have a backstage pass to one of the most influential touring bands in American music. And they brought their private slang with them.

“They Were All Kind of Chuckling at It”

Dave Reddix has described the early days of the term spreading through the Dead scene directly:

“I was backstage a lot of the time with these guys like Phil, David Crosby, and Terry Haggerty — getting high and using the term 420, and they were all kind of chuckling at it.”

— Dave Reddix, to Huffington Post

What the Waldos called each other at San Rafael High became what Phil Lesh, David Crosby, and Terry Haggerty called each other backstage at Winterland. Roadies picked it up because roadies were always in earshot. The extended Grateful Dead family adopted it because the Waldos used it constantly and it was useful.

How Deadheads Carried It Everywhere

The Grateful Dead toured relentlessly through the 1970s and 1980s, averaging more than 75 shows a year through much of that stretch. Their audience — Deadheads — was one of the most committed touring fanbases in music history. People followed the band from city to city for weeks or months at a time. They had their own parking lot economy (Shakedown Street), their own vocabulary, their own norms.

Cannabis was part of the culture, openly. Parking lot circles at Dead shows were a standard feature of the touring economy. The word “420” — short, memorable, useful as a code in public spaces — spread through this network the way any shared language spreads: person to person, show to show, summer to summer. A Deadhead from St. Louis picked it up in Indianapolis, used it at home, taught it to friends who weren’t at the show. That process repeated thousands of times.

December 28, 1990: The Flyer at the Oakland Coliseum

On December 28, 1990, the Grateful Dead played the Oakland-Alameda County Coliseum in the Bay Area. Someone in the parking lot was handing out flyers. One of those flyers ended up in the hands of Steve Bloom, the news editor of High Times.

The flyer invited recipients to gather on April 20, 1991, at 4:20 p.m., in Marin County — the original Waldo territory — for cannabis consumption. It explained the “420” term and tied it back to the Waldos (though it didn’t name them).

Bloom took the flyer back to the High Times office in New York. He published it in the May 1991 issue. That was the first time “420” received national print exposure. By the end of 1991, the magazine’s readers across the country knew the term.

1998: Steve Hager Verifies the Origin

Between 1991 and 1998, High Times ran various speculative explanations for the origin of “420” — the police-code myth, the chemical-compound myth, the Dylan-math myth. In 1998, Larry Schwartz (Waldo Larry) finally had enough and called the magazine.

Editor-in-chief Steve Hager — cannabis culture historian, founder of the Cannabis Cup, and the person arguably most responsible for documenting cannabis history in the 1980s and 1990s — flew to San Rafael. He met with the Waldos at length, examined their postmarked letters and physical memorabilia, interviewed classmates, and walked the San Rafael High School campus. He concluded the Waldos’ story was genuine and published the true origin in High Times.

That 1998 article is why the origin is now a matter of settled journalism rather than folklore, and why the Oxford English Dictionary, when it added “420” to its lexicon in 2017, had a well-documented citation trail to work from.

The Dead’s Place in Cannabis Culture Generally

Even without “420,” the Grateful Dead would loom large in cannabis history. The band was openly pro-cannabis. Shows were famous for their cannabis-friendly atmosphere. The band members gave interviews about their own use for decades. Jerry Garcia is one of the most-quoted figures in cannabis culture memorabilia.

But “420” specifically is the Dead’s most durable linguistic contribution to cannabis culture. A code word invented by five kids in Marin would have stayed in Marin without the Dead’s tour network to carry it. A flyer in a Coliseum parking lot would have been an unremarkable piece of trash without a High Times editor standing there to pick it up.

That’s how an inside joke from San Rafael High School became a global cannabis holiday, an Oxford English Dictionary entry, and the number on a dispensary’s front door in every major American city. The Waldos wrote it. The Dead delivered it.

For the Waldos’ own story in detail, see the Waldos origin page. For the full origin including myths debunked, see what is 420. For 420’s concentrate-focused counterpart, see 710 Day.