More theories:
-Bob Dylan theroy
In Bob Dylan's song, 'Rainy Day Women #12 && 35,' the lyrics contain 'everybody must get stoned.' 420 comes from the title, as 12 * 35 = 420.
-Highway 420
In Ontario, Canada in the 60's, marijuana grew freely on one of the Highways. This highway was later renamed in 1972 as Highway 420.
-There are 420 chemicals in Weed.
-4/20 is police code for Maryjane.
-The Grateful Dead Theory
Supposedly, on April 20th (some year between 65' and 75') the band was trying to buy some weed. They put together all the money they had on their persons at the time, and it amounted to $420. On April 20th, The Grateful Dead bought $420 dollars of weed, and after they realized the coincidence, they decided that in light of the "herbal" phenomenon, they would smoke before any/every show, at 4:20 PM because most Dead shows started around 5ish. During the show, the Dead would entertain their audiences with stories about what happened before the show, or just any stories that they had. They would usually include any crazy "Trips" or "Thoughts" they had while they were high. Normally, in the middle of someone's story, another band member would chime in and say "Yeah, but you weren't feeling that way until 420". Once the hippies caught on, it was just a spiral Up from there.
- It was mistakenly reported that there were 420 atoms in one molecule of the
Ganja, and later found to be incorrect, but not until the drug culture had adopted the number as a code for marijuana.
-There are 4 oxygen molecules and 20 carbon molecules in THC.
-420 stands for April 20th, which is Adolf Hitler's birthday, which many people in the Netherlands (home to Amsterdam) and Germany celebrated during Hitler's time by drinking alcohol and smoking marijuana. The tradition then made its way over to the United States.
-The term refers to the birthday of Bob Marley he was born on April 20 hence 4/20 and shortened to 420. He is the universaly proclaimed leader of the religious use of marajuana.
-April 20th is the best time to plant your seeds for pot growing season. your plant will get just enough sunlight just enough water.
-It's a sticker that stupid potheads put on their vehicles to advertise to police that if you pull me over you'll probably find weed, pipes, roaches, and maybe even a firearm.
-One rumor of its' origin comes from Proposition 420 which was to legalize weed, but failed.
-The temperature in degrees Farenheight which marijuana has to be heated to to work.
-There is a 4:20 verse in the Bible, about how God planted the seed.
-Because a Dodge Viper will go 420 mph and ALL stoners want to do burnouts in the driveway of their grow house with a Viper (n. see Trevor's monster grow).