Laurie MacEachern doesn't grow tomatoes or roses in her backyard garden.

The director of the Medicinal Cannabis Patients Alliance of Canada lovingly tends to roughly a dozen bushy green marijuana plants outside her modest home south of Ottawa. 

MacEachern's garden is hidden away behind a ramshackle wooden fence. But the pungent aroma given off by her prized plants hits you long before she unlocks the gate. 

"The smell is just amazing," MacEachern says, using scissors to trim back thick stalks dense with narrow leaves and dark, fat buds. 

MacEachern has government permission to grow her own supply of medical marijuana.

Her garden provides her with a year's supply, which she uses to treat chronic symptoms from a number of ailments, from back pain to depression. 

"What it gives me is a year without pain," she says. "A year without muscle spasms, a year without being so depressed that I want to end it all."

MacEachern and other marijuana advocates ascribe almost magical healing qualities to their homegrown medicine. 

But starting next year, she and thousands of other medical marijuana users will have to dig up their gardens and start buying only from suppliers approved and licensed by Ottawa. 

Health Canada announced the changes in June, which are now beginning to come into effect. 

Starting Oct. 1, licences will no longer be issued to people who wish to grow their own medical marijuana. As of April 2014, the practice will be outlawed. Anyone using medical marijuana will need to get it from a licensed medical supplier.

Cost to rise for users

Ottawa says it's acting to weed out abuse in the system and to ensure quality control over a medicinal product whose popularity is growing rapidly. Health Canada says that when the medical marijuana program was established in 2001, there were fewer than 500 authorized users across the country. That figure has since grown to more than 30,000 and is expected to keep rising. 

But marijuana advocates and some small growers worry the changes will end up driving medical marijuana users back underground. 

Sitting among her own small crop of marijuana plants, MacEachern has no doubt about how the changes will affect her.

Laurie MacEachern

As of April 2014, Laurie MacEachern and others who used to grow their own medical marijuana will have to buy it from a licensed medical supplier. (Tom Parry/CBC)

"If it goes forward the way it’s intended, I will not be able to medicate unless I do it illegally," she says.

MacEachern says she can grow her own cannabis for just pennies a gram. The federal government is predicting licensed suppliers will sell a gram of medicinal marijuana for roughly $7.60 when the new system comes into effect next year. 

Ottawa will allow the market to decide whether the price goes up or down. With more than 150 firms bidding to become suppliers, the thinking is that costs could eventually fall, though there's no guarantee.

There have been calls for Ottawa to rethink its new policy. The BC Compassion Club Society, which helps supply medical marijuana to patients who need it, made a submission to Health Canada earlier this year in which it urged the government to continue to allow users to grow their own cannabis.

"The elimination of the licences represents an unconscionable cost increase to patients, many of whom are already burdened by extensive medical expenses," the submission noted. 

"Many find that cultivating their own medicine can be an integral part of their healing process. For those patients, the loss of autonomy, and the disruption of their medicine supply represents a severe impact on their quality of life."

Despite such arguments, the federal government isn't prepared to water down its proposals. That has led to criticism not just from marijuana activists but also from the Opposition in the House of Commons. NDP Leader Thomas Mulcair yesterday lashed out at the government over its proposed changes.

"Fact-based decision making is what Canadians are allowed to expect from their government, not decision-based fact making," Mulcair said.

"On medical marijuana, let's not make any bones about it, the Conservatives have never been in favour," the NDP leader added. 

"So, what they're trying to do is to make it increasingly difficult bureaucratically .... making it extremely difficult in fact to have access to that."