Business has been smokin' at one hydroponics shop and warehouse in Surrey, B.C. ever since two U.S. states legalized the possession of marijuana through ballot initiatives last November.

On any given day, courier vans and transport trucks join a steady stream of walk-in customers at Pacific Northwest Garden Supply and Green Planet Wholesale Ltd., ready to pick up or purchase hydroponics equipment and nutrients to grow medical marijuana and organic food products.

The owners say sales have quadrupled in the last three weeks alone, and the multi-million-dollar businesses now employ about 60 people, including three new members of a sales team.

The owners say they even have plans to open a new distribution facility in Washington state, somewhere near Bellingham or Seattle, in the next 90 days.

"I say a good portion of (the growth) would be the initiatives that have taken place," said co-owner Steven Betts, who says he's been involved in the hydroponics industry for about 20 years.

"I think there's been more of a social acceptance of that for, you know, medical benefit. So people are kind of getting over the social stigma of it, and they're jumping into it. Plus, there really is a big movement towards just general home gardening."

The companies' other co-owner Justin Cooper said the hydroponic business has "come out of the shadows" in the last five to 10 years because people are also accepting it as a better way of growing healthier plants.

Colorado allows small grow-ops

The ballot initiatives behind the U.S.-based business boom were approved in Washington state and Colorado Nov. 6, 2012 and allow adults over the age of 21 to posses up to an 28 grams of marijuana.

In Colorado, users can also grow up to six marijuana plants in a private, secure area, although under U.S. federal law the plant still remains illegal.

Betts said about 40 per cent of their sales now go to the U.S., and products are distributed through centres located in California, Colorado and Michigan.

But the headquarters for the companies' retail, wholesale and manufacturing operations remain in a 1,980 square-metre warehouse in Surrey.

The facility distributes equipment to purify water for plant nutrients through a reverse-osmosis process and bottling and labelling machinery, and has shelves stocked with artificial-lighting and ventilation systems, growing structures and tents, air conditioning units, non-toxic pesticides, and plant nutrients.

Hanging near the checkout counter is a giant yellow sign, warning customers that they'll be asked to leave if they mention any "illegal substances."

"We've never been about doing things illegally," said Betts. "We're not martyrs. We don't try to be radicals or rebels. We're really about how to garden and how to garden efficiently."

Medical cards drive Michigan market

Lee Bryant, owner of Great Lakes Garden Wholesale, the Michigan-based U.S. distributor of Green Planet products, said most of the customers who are buying the products in his state are doing so with a medical card for marijuana.

In Michigan, he said, the state allows individuals to obtain a medical card that allows them to grow marijuana for themselves or for other patients, as a caregiver.

Bryant credits Green Planet's success on its use of high-quality products such as reverse-osmosis water and raw nutrients, and its decision not to use plant-growth regulators, which may grow larger plants but are harmful to the health of consumers.

"We got the product in and it's done phenomenally," he said. "I mean, we have absolutely changed the market in Michigan and now in quite a few other states in the U.S. that have become big supporters of the product."

Big-box marijuana supplies?

Because of that success, one university academic is questioning how long it will be before other, larger companies get into the game, too.

Stephen Easton, professor of economic at Simon Fraser University in Burnaby, B.C., and a senior fellow at the Fraser Institute, said whenever there's a big margin of opportunity in business, others begin looking.

"You've got to believe that somebody else is going to move in, too," said Easton. "You think that Wal-Mart's not going to notice or Home Depot?"

Easton said he's not surprised Americans are drawing resources from a Canadian company.

"Obviously, they have some expertise," he said, adding social attitudes towards marijuana have changed, although the laws in Canada have not.

"[In] the olden days... it was sort of demon marijuana, you know, turn you into a... dope fiend," he said. "I think a large part of society is past that, but the laws are sufficiently slow in reacting."

Cooper and Betts said they're already looking at the companies' future growth. Cooper said while a portion of the company's business is focused on medical marijuana, its long-term vision is food production, giving people the ability to grow healthier, more environmentally friendly, more sustainable crops.

"We've got to stay ahead of the curve," said Cooper.

"Everything we do is always, 'how can we make this better?' That's one of the things we say all the time. 'What is it going to take to make this type of product better than what currently is on the market?'"