PHOENIX — Medical marijuana patients could learn later this month if they have a constitutional right to grow their own weed.

Two medical marijuana patients have sued the state after Health Director Will Humble denied them permission to grow their own plants. The law approved by voters in 2010 allows only those living more than 25 miles from a state-licensed dispensary to grow their own plants, which Humble says covers just about everyone in the state.

But Michael Walz, who represents the patients, says Humble’s action violates a 2012 voter-approved constitutional amendment that overrules any law that requires anyone to “participate in any health-care system.”

Walz contends that means individuals can’t be forced to give up the cheaper option of growing their own plants.

Maricopa County Superior Court Judge Katherine Cooper said she will begin unraveling the conflicting voter-approved measures on Oct. 18, when she considers a bid by the Department of Health Services to have the lawsuit thrown out. Assistant Attorney General Gregory Falls hopes to convince her nothing in the Arizona Constitution about the rights of patients to choose their own health care extends to making their own drugs.

If Cooper doesn’t dismiss the suit, she is ready for the next step: She scheduled an Oct. 21 hearing to allow Walz to tell her why she should order Humble to let them have their plants.

If Walz ultimately succeeds, the implications go far beyond these two men. It would pave the way for similar rights for the approximately 40,000 individuals who already have been granted permits to possess the drug but are required to purchase their supply from one of the state’s nearly 100 state-regulated dispensaries.

“People are legally entitled, if their doctor gives them certification, to obtain and use marijuana for medical purposes,” Walz said Wednesday.

“Many people cannot afford the prices that are charged by dispensaries,” he continued. “Therefore, they need to be able to grow their marijuana for themselves.”

And, Walz said, for some patients, the strain of marijuana is crucial.

“A particular strain may be effective to treat their specific condition and they need that strain,” Walz argued. “They can’t depend on a dispensary to make the effort of providing a specific strain for any particular person.”

Humble, however, points out that voters themselves approved the provision in the 2010 law that says the right to grow your own marijuana disappears if there is an available dispensary.

Walz dismissed that as irrelevant.

“I don’t know that the voters were aware of that specific provision,” he said.