The short answer
Colorado legalized cannabis in two steps. Voters approved medical cannabis in 2000. Voters approved adult use on Nov. 6, 2012, through Amendment 64. The amendment took effect on Dec. 10, 2012, when Gov. John Hickenlooper signed the ballot proclamation. Retail stores opened on Jan. 1, 2014.
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Timeline
- Nov. 7, 2000: Voters approve Amendment 20, the medical cannabis measure.
- 2001: The Colorado Medical Marijuana Registry begins issuing patient cards.
- Nov. 6, 2012: Voters approve Amendment 64 with about 55 percent of the vote.
- Dec. 10, 2012: The governor signs the proclamation. Adult possession and home grow become legal under state law.
- Jan. 1, 2014: The first licensed retail cannabis stores open.
Medical cannabis: 2000
Amendment 20 added Article XVIII, Section 14 to the Colorado Constitution. It allowed patients with a doctor's recommendation to possess and grow limited amounts of cannabis. The state created a registry of patients. The measure passed with 54 percent of the vote.
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Adult use: Amendment 64
Amendment 64 added Article XVIII, Section 16 to the Colorado Constitution. It made possession legal for adults 21 and older. It set a state framework for licensed cultivation and sales. Colorado and Washington were the first two states to pass adult-use laws in the same election.
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The amendment did not make sales legal at once. The state needed rules for licenses, testing, packaging and taxes. The legislature passed HB 13-1317 in 2013 to build that system. Stores opened the next year.
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What Amendment 64 allows
- Possession of up to 1 ounce for adults 21 and older.
- Home grow of up to 6 plants per person, with 3 mature flowering plants.
- Gifts of up to 1 ounce to another adult, with no payment.
- Local bans on stores and cultivation.
- No public use. No use in a car.
Federal status
Cannabis remains a Schedule I drug under federal law. Colorado law does not shield anyone from federal charges. Federal prosecutors have not targeted state-legal cannabis businesses in recent years, but the conflict in law remains.
Changes after 2014
The legislature has amended the rules several times. Later laws added delivery licenses, social consumption areas and limits on concentrate sales. Local rules still control store locations, hours and zoning. Check the current Colorado Marijuana Enforcement Division rules and your city code before you buy or grow.