(Adds reaction from federal health minister, paragraphs 8-10)
By Julie Gordon
VANCOUVER, Feb 24 (Reuters) - A federal court judge in Vancouver on Wednesday ruled that medical marijuana patients have the Constitutional right to grow their own cannabis, striking down a ban introduced by Canada's previous Conservative government.
The court suspended its decision for six months to give Ottawa time to respond.
A group of British Columbia residents took Canada to court in 2013, arguing a new law requiring medical marijuana patients to buy cannabis from licensed producers, instead of growing their own, was unconstitutional.
They said marijuana grown under the government system was too expensive and did not allow them to control the strains and dosages of their treatment.
The then Conservative government, which overhauled its medical marijuana program in 2013, argued that its mail order system was safer for both the patient and other Canadians, who could be hurt by unsafe home-grow operations.
In his decision, Federal Court Judge Michael Phelan said restrictions imposed by the Marihuana for Medical Purposes law were arbitrary.
"The access restrictions did not prove to reduce risk to health and safety or to improve access to marihuana - the purported objectives of the regulation," he wrote.
In the election last October, the Liberals defeated the Conservatives. In Ottawa, new federal Health Minister Jane Philpott told reporters she would study the ruling.
Philpott stressed the matter had nothing to do with recreational marijuana, which the Liberals pledged during the election campaign to regulate and legalize.
"We understand that of course Canadians who require medical marijuana for the purposes of addressing their illness need to have access to it," she said.
The Liberals have not addressed their plans for medical marijuana at length.
Last June, Vancouver city councillors voted to license marijuana dispensaries, which operate outside the current federal framework, becoming the first Canadian city to regulate retailers selling the drug.
Shares of medical marijuana producers plunged on Wednesday after the ruling, with Canopy Growth Co falling 10.79 percent to C$2.81, OrganiGram Holdings dropping 9.88 percent to 73 Canadian cents and Aphria Inc down 12.4 percent to C$1.13. (Additional reporting by David Ljunggren in Ottawa; Editing by Alan Crosby and David Gregorio)