Colorado legalized recreational marijuana in 2012, but it has a Green Rush nagging black-market problem. Law enforcement and state lawmakers attribute the black-market problem in part to weak restrictions on who can grow pot. The Colorado state constitution authorizes people over 21 to grow their own pot, or to assist someone else in growing pot. That language allows groups to designate a single farmer to care for their marijuana plants, allowing them to avoid pot taxes that approach 30 percent, depending on the jurisdiction. But police groups and Hickenlooper, a Democrat, have called on lawmakers to curb the practice of assisting other recreational pot users. The bill had already passed the House. The governor plans to sign another bill this week in the states pot crackdown. It limits the number of marijuana plants that can be grown in a home to 12 plants, which would force medical marijuana users authorized to grow more than 12 plants to grow it in agricultural or commercial locations or to buy it from dispensaries that tax marijuana. Hickenlooper plans to sign that bill this week, his office said.