Marijuana initiative may make Colo. ballot DENVER, Jan. 5 (UPI) -- Backers of a campaign to legalize marijuana in Colorado say they've gathered sufficient signatures to put the measure on the state's ballot. The campaign said it has collected about 160,000 petition signatures and delivered them to the secretary of state's office Thursday, The Denver Post reported. The initiative needed only about 86,000 signatures from valid Colorado voters to make the ballot. "We were overwhelmed with the support we received," initiative proponent Brian Vicente said. If certified by the secretary of state, the initiative will put a proposed constitutional amendment before voters to legalize possession of up to an ounce of marijuana for any purpose by people 21 or older and allow people to grow up to six plants in their homes. Consumption of marijuana in public would not be allowed. Supporters have dubbed their petition effort the "Campaign to Regulate Marijuana Like Alcohol," though they said the initiative would create stricter regulations on marijuana than those currently applied to alcohol.