Alaska law now explicitly defines how many personal-use cannabis plants a household can have, doubling the number of plants assumed legal under the state marijuana board's definition.

Up to 12 plants per household are now legal under state law — if at least two adults over the age of 21 are living in the residence.

The language was included in House Bill 75, which passed the Legislature in May. It was signed into law Thursday by Gov. Bill Walker and took effect Friday.

Bill sponsor Rep. Cathy Tilton, R-Wasilla, said Friday that law enforcement had asked legislators to establish an explicit number of plants in law. They wanted a "bright line of where (a grow) went from a personal use to a commercial use establishment," Tilton said.

Under Alaska's 2014 initiative, each person can possess up to six plants, three of which may be flowering. But the initiative said nothing about how many plants were legal in one household.

Regulators worried that people would try to create illegal commercial grows by amassing a number of residents' plants under one roof in a so-called "community grow" or "cultivation center."

To avoid this, the Marijuana Control Board voted to define "possession" as having the plants under one's physical control, which effectively set the legal plant limit at six per household.

The passage of HB 75 changes that, making it explicit that households can have up to 12 plants, six of which may be flowering. Two adults over the age of 21 would have to be living in the home.

In their homes, Alaskans can possess as much marijuana as those plants produce. In public, people can possess up to an ounce legally.

Legislators arrived at the 12-plant limit based on the average number of adults per household in Alaska, Tilton said. They also analyzed how much cannabis one plant could produce, and tried to compare ounces of marijuana to the legal amount of homebrew a person can possess — 100 gallons — in an attempt to stay true to the oft-repeated campaign slogan of regulating marijuana like alcohol.

The second major piece of the bill adds language that allows established villages to opt out of the commercial marijuana industry — language that was lacking from the 2014 law allowing other types of local government to opt out.

Municipalities had asked to include this language, giving villages the same powers as boroughs and cities – some of which, like Wasilla and Palmer, have already opted out of the industry.