The Denver City Council, which on Monday thought better of trying to stop people from smoking pot on their own porches, is now considering limits on home cultivation that go beyond those imposed by Amendment 64, Colorado's marijuana legalization measure. A bill proposed by Jeanne Robb, the same councilwoman who wanted to ban marijuana consumption in outdoor areas on private property, would cap the number of cannabis plants at 12 per household, regardless of how many adults live there. Amendment 64, by contrast, allows every resident who is 21 or older to grow up to six plants, "notwithstanding any other provision of law." It says doing so "shall not be be an offense under Colorado law or the law of any locality," as long as "the growing takes place in an enclosed, locked space, is not conducted openly or publicly, and is not made available for sale." Since Amendment 64 is now part of the state constitution, it is hard to see how Robb's proposed ordinance could pass legal muster.

Leaving aside that rather significant point for the moment, Robb's justification for the 12-plant-per-dwelling limit, which parrots the talking points of the anti-pot group Smart Colorado, seems pretty weak. "The police are very worried about the homegrows and the problems they could cause," she tells The Denver Post. Specifically, she claims to be worried about "fires, pesticide use, the mold, structural damage, children who might be living in these areas, and THC on surface areas." Writing at HomeGrow.CO, a site that covers home cultivation under Amendment 64, Kris Kaiser debunks these concerns one by one. Regarding "THC on surface areas," for example, he says:

I am not sure what Smart Colorado or the Council Woman thinks happens when cannabis is grown. THC IS NOT SPEWED OUT OF THE PLANT, contaminating surfaces in the area….I checked, [and] apparently dispensaries do NOT have a problem with THC contamination on surfaces. I figured since they have 1000's of plants, SURELY they would have THC contamination issues. But no, they didn't seem to know what the heck I was talking about. So I explained it to them, [and they] still [have] no idea.

More to the point, any valid safety concerns would apply to growing 12 plants as well as 13 (or 18), and they can be addressed without arbitrarily denying Coloradans their constitutional rights. According to the Post, "Robb said police have stories of homes with dozens of plants, including an 80-year-old grandmother with more than 100 plants in her home." Robb's bill has nothing to do with a situation like that, since 100 plants is already 94 more than any one person is allowed to grow under Amendment 64.

Granted, homes with three or more adults, all of whom want to grow marijuana and at least two of whom plan to do so up to their personal limits, are fairly unusual. But Kaiser argues that Robb's restriction would disproportionately affect college students, families of modest means, and people caring for elderly parents who use marijuana as a medicine, all of whom are especially likely to live in households that include more than two adults.

Robb and her friends in the police department may be offended by the idea of three roommates growing a total of 18 plants and sharing the produce with their friends (one ounce at a time). Furthermore, it is in the city's financial interest to keep a lid on DIY production so as to maximize revenue from the taxes on sales at state-licensed stores. But the informal, nonprofit distribution of homegrown pot is protected by Amendment 64, and it can serve as an important restraint on politicians' urge to tax and regulate.

Update: Christian Sederberg, a Denver lawyer who worked on the Amendment 64 campaign, has this to say about Robb's proposed limit:

One could argue that it is unconstitutional, based on each individual being constitutionally able to grow/possess up to six plants (three mature). But I also think the localities have the right to impose reasonable restrictions. Unless the court found that collective growing is a "fundamental right," the city would likely succeed in court if this 12-plant limit were challenged. So in my opinion, it isn't necessarily consistent or inconsistent with A64. It is definitely a gray area.

I'm not sure "collective growing" is really the issue. If Amendment 64 protects the right of each adult to grow six plants (which it does) but the city of Denver tells some adults (those who live with two other pot growers) that they may not do so, that seems pretty inconsistent to me.