What is the Origin of 420 (April 20) Weed Day?

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by Morgan

Last update:

August 29, 2023

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If you love smoking and growing cannabis, you probably chuckle every time you hear “420”, just like all hemp fans around the globe. But what is the origin of 420?

How did a seemingly random number become the most popular code for marijuana out there? Let’s dive into the interesting story of a group of teenagers, a treasure hunt, and a Louis Pasteur statue (the scientist responsible for giving us safe milk)!

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But what really happens on 4/20?

You might not know this, but 420 is not used just to denote marijuana in random conversations.

Each year, on April 20 (4/20), pot smokers worldwide celebrate the only national holiday of the cannabis world, which involves defying the negativity and taboo associated with cannabis, smoking it in public, and holding (political) events to raise awareness about its benefits.

April 20 is seen as the condensation of a global movement in support of cannabis — people have called it “half celebration and half call to action”. It’s not just an event; it’s a festival, a counterculture day, and a powerful way to create awareness about the positive aspects of cannabis, for e.g. its use as medical marijuana

What is NOT the origin of 420…

But just like every great story, there are a lot of myths surrounding the 420 references. Let’s get them out of the way first.

420 chemicals in the marijuana plant

Some people believe that the marijuana plant has four-twenty chemicals and that’s where the term 420 came from.

Not true! While the plant does have more than 400 chemicals, no one really knows the exact number.

Bob Marley’ death

These people believe that 420 comes from the day Marley died — but he died on 11th May, so that’s just another made-up story.

Hitler’s birthday

This is probably the wackiest myth of all. These people believe 420 has something to do with Hitler’s birthday. This is so bizarre (and non-sensical) that we won’t even attempt to debunk it.

Bob Dylan’s “Rainy Day Women #12 & 35”

Many people believe that 420 was born after the Bob Dylan song, “Rainy Day Women #12 & 35”, where the singer sings everybody must get stoned.

Multiply 12 by 35, they say, and you get 420. But not so fast…

Bob Dylan has never confirmed this, and honestly, it’s a bit of a stretch.

California’s law — the 420 criminal code

Other people believe that 420 comes from the fact that the California penal code uses 420 to denote the offense of smoking (or distributing) marijuana. But that’s not quite true because 420 in California applies to you if you try to obstruct entry on public land.

The 420 police code

Then there are people who believe that 420 refers to a police radio code that they use when they catch someone messing around with marijuana.

Unfortunately, that’s not true either. In fact, only one police department in the US (the San Francisco police) has a code 420, which they use to denote juvenile disturbance.

It’s interesting how quite a few myths about 420 revolve around law and order. A bit ironic, don’t you think?

So, what’s the real origin of the term 420?

The real story revolves around a group of 5 friends. Steve Capper, Dave Reddix, Jeffrey Noel, Larry Schwartz, and Mark Gravich used to attend the San Rafael high school in the early 1970s. Being avid users of weed, the boys used to hang out by a wall outside San Rafael for smoking marijuana, which is why they called themselves the “Waldos”.

The Waldos had a designated meeting point within the grounds of San Rafael too — a Louis Pasteur statue — where the boys would meet to plan and discuss their hunt for a cannabis plantation based on a treasure map. Unfortunately, that plan never succeeded.

Even though the Waldos couldn’t find the hidden hemp plantation, they would continue to hang out by the wall outside the San Rafael high school to smoke pot. And of course, they had to invent a secret word for marijuana — a code for smoking.

They couldn’t just go on roaming around San Rafael (or their houses) mentioning marijuana in their conversations, right?

Now, the Waldos used to meet every day at 4:20 pm to get high — this was an ideal time because high school was over and their parents wouldn’t be home yet. Sweet, unsupervised, freedom. And this is what they chose as their secret word for smoking pot — 420 came from 4:20 pm.

How did the Waldos succeed in making 420 so popular?

After all, they were just a group of ordinary high school boys — they weren’t celebrities or politicians. How, then, did 420 gain so much popularity?

Sometime later, Dave Reddix’s (one of the Waldos) brother helped him get a job with the Grateful Dead bassist Phil Lesh as a roadie. And so, it’s believed that it was the band Grateful Dead that was responsible for bringing 420 into the mainstream.

Grateful Dead fans distribute 420 flyers

In 1990, Grateful Dead fans in Oakland distributed flyers around the area, inviting people to celebrate the cannabis culture by smoking 420 at 4 20 p.m on April 20. Steve Bloom, who is an authority on cannabis and was then a reporter for the High Times magazine got his hands on one of these flyers.

In 1991, the magazine printed this flyer and continued to use the term 420 to refer to cannabis and the cannabis culture. So while the Waldos were the real inventors of 420, a Grateful Dead concert and a magazine publication are what it took for 420 to soar to popularity.

Is April 20 a holiday?

We wish it were, but right now, it’s just wishful thinking. You could probably call in sick and have a nice time but that’s up to you!

How to celebrate 420?

There are many ways to celebrate 420, and one of the most important things you can do is to educate yourself about the fact that the marijuana legalization campaign is really a push for equity. It’s been the people of color that have been the most affected by the so-called war on drugs.

And of course, there are many other fun things you could try like:

  • binge-watching TheWeedTube — it’s basically YouTube for hemp-lovers (and is mostly made up of people who got kicked off YouTube because, well, hemp is illegal!)
  • learning how to smoke weed politely. Yes, that’s a thing! Check out the Emily Post Institute guide High Etiquette
  • educating yourself on what modern science has to say about pot — an excellent place to start is Joe Dolce’s podcast Brave New Weed
  • learning about how to grow high-quality pot at home
  • reading our interesting guide on how to differentiate between male and female hemp flowers, which is really going to help you when you’re trying to grow some in your house
  • learning about the best grow-lights out there
  • mixing your love of cooking with your love for hemp with Bong Appétit’s Mastering the Art of Cooking with Weed
  • learning about the best seed banks of 2021

Remember, 420 came from the Waldos!

The next time someone tells you a wacky story about how 420 started, make sure you tell them how it really started with a group of high school boys, an American rock band, and a magazine!

Also, remember to celebrate 420 responsibly, read our weed hacks to thoroughly enjoy this day, and keep in mind the views of others. This is a controversial event, and not everyone feels the same way about it as you do. This doesn’t mean everyone dislikes you — it just means they’re a little less aware right now and things will improve!


1. What are some theories about why April 20th became known as weed day?

There are many theories about why April 20th became known as weed day. Some people say it is because that is the date that Bob Marley died, and he was a famous marijuana smoker. Others say it is because April 20th is 4/20 in American dating notation.

2. What are some of the events that have taken place on April 20th?

April 20th is a day that has been associated with several events throughout history. Some of these events include the Columbine High School massacre, the Battle of Lexington and Concord, and the signing of the Louisiana Purchase.

3. How has the meaning of April 20th changed over the years?

April 20th has come to be associated with marijuana culture, as that is the date of a major cannabis-related event in the United States. However, the original meaning of the date was quite different. April 20th was originally chosen as a day to commemorate Adolf Hitler's birthday.

4.  How Did April 20 Weed Day Start?

There are many myths and legends about how April 20 became known as Weed Day, but the most commonly accepted story is that it originated with a group of high school students in California in the early 1970s. The students would meet every year on April 20 to smoke marijuana, and the tradition gradually caught on with other cannabis users across the country. Today, April 20 is widely recognized as a day for celebrating and enjoying cannabis culture.

5. What is the Purpose of April 20 Weed Day?

April 20th is known as "Weed Day" because it's a day where people celebrate and use cannabis. Some people believe that the date was chosen because 420 is police code for marijuana possession. Others believe that it was chosen because the date falls on 4/20 in the US calendar.

🌿  Join my "growing" community 
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cannabis farmers! 👩‍🌾

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from seeds to smoke! 
— Morgan, 420GreenThumb 🌱

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About the author 


I discovered the benefits of Cannabis at a young age in 2002, with years of trial and error, my knowledge grew just like my plants. As my love for cannabis unfolded I began to teach and learn, trying to gain as much information and practical growing experience.

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