Governor Sununu has vetoed a bill that would have allowed medical marijuana patients to grow their own plants.

In his veto message, the governor cited concerns about more marijuana ending up on the black market.

Backers of the proposal, which would let qualified patients to grow up to six plants after registering with the state, said the home grow option would lower costs and increase accessibility for patients.

The bill passed the Senate on a 14-10. It passed the House on a voice vote, after being endorsed by the House Criminal Justice and Public Safety Committee 17-4.

Sununu, in his veto message, writes that the state has reasonable regulations to ensure responsible operation of medical marijuana dispensaries. "This bill would bypass those public health and safety guardrails and make the job of law enforcement significantly more difficult. Furthermore, it could serve to undermine the protections we have built within the Alternative Treatment Center system by making those facilities less sustainable."

It was the 43rd bill Sununu has vetoed this year. (Related: N.H. Veto Tracker)

The N.H. Association of Chiefs of Police opposed the legislation.

There are currently five dispensaries in New Hampshire for therapeutic cannabis, and more than 7,000 people and nearly 450 caregivers are enrolled in the program.

The bill had bipartisan support, particularly in the House. It was sponsored by Sen. John Reagan, R-Deerfield, and Rep. Renny Cushing, D-Hampton. In a phone interview Friday, Cushing said it is an injustice for a person to be charged with a felony "for growing their own medicine."

Cushing said the concerns over diversion have not materialized since medical cannabis dispensaries first opened more than three years ago. "The idea that somehow there'd be diversion doesn't make sense," he said.

Matt Simon, New England political director for Marijuana Policy Project, called the veto a "heartless decision."

In a statement, he said, "The governor does not seem to understand that many patients are relying on cannabis to stay off opioids but are unable to afford a consistent supply from dispensaries. Patients should absolutely not be considered criminals if they grow a few plants for their own use in the 'Live Free or Die' state."