As Canadians prepare for legal recreational cannabis, farmers are facing a difficult choice: whether they should use their land to grow cannabis or food.

Some farmers are in support of the idea of shifting to cannabis cultivation, but the idea is drawing opposition from others.

In B.C.'s Central Saanich, a district municipality in Greater Victoria, a plot of agricultural land was set to become a large-scale medical marijuana production facility with 21 greenhouses.

Then, petitioners showed up, calling for a ban on cannabis production on farmland and arguing farms are for food.

"We're not against marijuana," said Ken Mariette, spokesperson for the group Citizens Protecting Agricultural Land.

"We just don't want it grown on prime farmland."

Ken Mariette is a spokesperson for the group Citizens Protecting Agricultural Land, based in Victoria. He argues that that marijuana production isn't the same as growing land-based crops, like corn, and using farmland for cannabis production threatens food security. (Khalil Akhtar/CBC)

But Shawn Galbraith, the founder and CEO of Evergreen Medicinal Supply, told CBC Radio's On the Island that his company's marijuana production facility should indeed be on agricultural land.

"This is an agricultural business.… We feel that it should rightly be on agricultural land. We're producing plant material, which typically wouldn't be grown in an industrial area," he said in a December 2017 interview.

As well, he argued, "it's difficult to get large tracts of industrial land for this type of operation, and in order for our company to be competitive in the future market, we will require some scale."

New legislation doesn't favour marijuana growers

The Citizens Protecting Agricultural Land group cropped up after the facility was proposed in Mariette's neighbourhood, on land that had been used as a dairy farm for generations.

The current landowners planned to retire and sold the property to Evergreen, a medicinal marijuana company. With Health Canada approval, it looked like a done deal.

The argument came to a head this summer when the provincial government stepped in and changed the rules governing agricultural land use.

The new legislation gave local governments and First Nations the ability to block marijuana-growing operations on land that is part of the Agricultural Land Reserve — the provincial zone in which agriculture is recognized as the priority use — under certain conditions.

It was a fatal blow to the proposal that Mariette and his neighbours campaigned against from the beginning.

Marijuana growers could face similar challenges in other jurisdictions that have a covenant placed on farmland. Those covenants could restrict what any future owner may do with the land.

Is farmland meant for food?

Mariette argues that that marijuana production isn't the same as growing land-based crops, like corn. Growers build concrete-floored, climate-controlled greenhouses.

Those greenhouses could go on industrial land, but manufacturers prefer the cheaper option of rural agricultural land. That's what worries Mariette.

"By concreting over prime farmland, you ruin future food security," said Mariette.

"You can't grow food on concrete pads. When you take the earth off, put in fill, concrete over 30 acres, build 21 150-foot greenhouses, you never get that land back again."

They're going to do what's best for our province in terms of revenue, not necessarily for protecting future food security. - Ken Mariette , Citizens Protecting Agricultural Land

But the question becomes far more complicated when you look at the reality of farming across the country.

In Canada, farmers grow tomatoes and cucumbers in climate-controlled greenhouses with concrete floors. Should those also be restricted?

Other non-food crops grown on agricultural land include Halloween pumpkins, hops and barley for beer, grapes for wine, tobacco and flowers.

"Not all of the [Agricultural Land Reserve] land is currently being used for food anyways," B.C. cannabis activist Dana Larsen told CBC News in a March 2018 interview. "I think it's a crop like any other."

But Mariette argues governments may be motivated by the potential tax revenue from marijuana production.

The federal government has agreed to give 75 cents of every dollar collected from taxes on legalized cannabis sales to provinces and territories, though municipalities have not been cut into the deal so far.

"In the end, if you're getting 75 per cent of the tax revenue as a municipality and as a government, it comes down to money and they're going to do what's best for our province in terms of revenue, not necessarily for protecting future food security," said Mariette.

The question of food versus cannabis is likely to come up more often, as legal recreational marijuana becomes a part of Canadian life and production moves out of illegal, hidden grow-ops and onto mainstream farmland.

Whether or not municipalities allow that is another story.