SALEM -- Gov. John Kitzhaber expressed concern Tuesday about how much marijuana Oregonians would be allowed to possess at home under the new legalization measure -- and he indicated that he might ask legislators to seek lower limits.

The governor, saying he has "many concerns" about the initiative approved by voters, questioned the logic of allowing voters to possess up to a half-pound of marijuana at home but just 1 ounce in public.

"The amount you can actually grow in a home-grow operation seems to me to exceed the amount that you're supposed to have legally," Kitzhaber told reporters. "I don't know how you enforce that."

Backers of Measure 91, which was approved by 56 percent of voters in the November election, say they purposely set higher possession limits at home to allow adults to grow marijuana and make concentrates and pot-laced edibles.

"Just like home brewing of beer and the home making of wine, you need to have reasonable rules for personal cultivators and hobbyists who want to produce their own marijuana," said Anthony Johnson, the measure's sponsor.

He said the measure allows people to possess four plants, which he said is what many growers believe they need to produce a reliable supply of marijuana. And Johnson said the possession limits in the measure reflect the kinds of amounts growers are likely to produce.

Sen. Ginny Burdick, D-Portland and the co-chair of a special legislative marijuana committee, said she also had some concerns about the home-possession limit because of fear that it could lead to diversions to the black market.

"We need to take our best shot at setting the right limit," said Burdick. She added that she is also working on a bill that would prohibit people from growing marijuana at home if they were ever caught selling it illegally.

Kitzhaber, speaking at an Associated Press event to preview the legislative session that begins Monday, did not say what kind of limits he wants to see.

Instead, the governor said he will lay out his general principles for marijuana regulation in a letter this week to the Oregon Liquor Control Commission. In addition, Kitzhaber said he also expects to ask legislators to make several legal changes in Measure 91.

The OLCC is charged under Measure 91 with regulating the market in recreational marijuana. The measure calls for possession to become legal on July 1 and for commercial sales to begin sometime after the start of 2016.

Kitzhaber opposed the legalization measure, saying he thought Oregon should wait to see how Washington and Colorado fare with legalizing the drug.

In addition to looking at the home possession limit, Kitzhaber also questioned whether the Oregon Health Authority should continue regulating medical marijuana separately from the new market in recreational pot.

"You need one regulatory body over both of them," said Kitzhaber, adding:

"One could ask, 'If you could use marijuana recreationally, why do you need a separate medical marijuana statute?'"

Medical marijuana patients and growers have been adamant about wanting to keep a separate program, and Measure 91 explicitly calls for that.

"It's premature to make drastic changes to the medical marijuana program at this time, especially before we've even implemented the rules for Measure 91," said Johnson.

Burdick said she supports continuing the medical marijuana program. But she said she wants to tightly regulate growers for that program to make sure they don't sell marijuana on the black market. She also said she's open to discussion about whether medical marijuana patients should have to pay the same taxes as recreational users.

-- Jeff Mapes

503-221-8209

@Jeffmapes