Dhar Mann wants you to know that he's just another entrepreneur.

Since he founded his company at the start of 2010, his chain of stores has grown strongly, and he says he expects to have 40 outlets by the end of the year, plus 25 more in 2013. He sees his business not just as a money-making enterprise but as a bastion of social responsibility, not to mention a catalyst for job creation.

Yet some neighborhoods don't want his stores to move in.

That's because Dhar Mann also wants to help people grow marijuana.

Mann is the CEO of weGrow, which bills itself as "the first honest hydro store," in reference to hydroponics, a common method for growing pot. Unlike some other hydroponics sellers, which Mann refers to as "hydrocrites," weGrow not only acknowledges but promotes the fact that its products are used to cultivate cannabis.

"I think the more that businesses such as weGrow portray themselves in a professional manner and the more that we can show that this industry is not what it's stereotyped to be, that there are legitimate business and tax revenues and jobs that we can create for the industry, the further we can enhance the medical marijuana industry into acceptance across the country," says Mann.

WeGrow opened its newest store in Washington, D.C., last week, and the small storefront contains an array of bright grow lights, complicated-looking watering systems, jugs of fertilizer, and bags of soil—everything but the plants themselves, all intended to help people grow the best ganja possible.

A proliferation of state laws legalizing medical marijuana has made stores like weGrow look like a more and more lucrative enterprise. Medical marijuana is now legal in 16 states, plus the District of Columbia. According to the AP, projections for the so-called green rush predict that the medical marijuana industry could generate nearly $9 billion over the next five years.

WeGrow may aim to be like any other business, but there are plenty of hurdles in its way. One is widespread stereotyping of marijuana users. Mann believes that weGrow can counter this by "normalizing" medical marijuana. His employees have told him that marijuana growers are from "literally all walks of life, from professionals to seniors to the physically challenged to soccer moms."

Then again, weGrow doesn't entirely dodge those stereotypes...alongside powerful fans and instructional books, for example, the D.C. store also sells Beatles' Yellow Submarine posters while a soundtrack featuring Bob Marley plays in the store speakers.

But aside from concerns about perception, of course, weGrow faces another, much more sizable hurdle: federal law. And though weGrow does not itself sell any marijuana, the federal prohibition against marijuana still poses problems that few other businesses face.

Try opening any other gardening store that prides itself on selling the works—hoses, fertilizer, hoes, soil—everything except the seeds and seedlings.

In addition, when the customers ask where they can get petunia seeds, don't tell them where to get them. That's the level of caution that Alex Wong, the owner of Washington, D.C.'s weGrow store, takes. He has an M.B.A. from NYU, and as a businessman, he says it's frustrating that the key ingredient to growing pot—the pot itself—is the one thing he cannot sell.

When customers ask where to get a plant, he says, "We can't even recommend anything. We say things such as, 'We have no idea where to get them. They're out there somewhere.' But even before that we have to say, 'We have to see your medical marijuana card.'"

That's because, unlike most states that allow medical marijuana, Washington, D.C., prohibits patients from growing their own plants.

Wong and other proponents of medical marijuana decry laws against it as unfairly preventing people from getting helpful medicine. "Honest" stores like weGrow, they say, can make things a little easier for those patients.

"It is helpful for patients to be able to walk into a garden supply store and be able to talk about cannabis directly rather than use euphemisms like 'tomatoes,'" says Robert Raich, an attorney specializing in medical cannabis law.

Mark A.R. Kleiman, a professor of public policy at the UCLA School of Public Affairs, believes that, while the plant has real benefits for certain patients, the rhetoric surrounding medical marijuana is in many ways a smokescreen.

In California, where medical marijuana has been legal since 1996, "most of the people in the medical marijuana business are in the marijuana business," he says. "The physicians [who prescribe marijuana] are mostly not practicing medicine. They're selling recommendations. They market themselves that way."

So when the District of Columbia opens its first dispensaries, the staffers at weGrow could end up selling to recreational users posing as real patients. And if weGrow truly prides itself on selling to patients and not recreational stoners, Wong could find himself conflicted at the possibility that new revenues might come from people without a true medical need for pot...once again, a concern that doesn't keep petunia sellers up at night.

While weGrow wrestles with these philosophical questions, it must still deal with everyday business realities. And the path hasn't been all rainbows; Derek Peterson, Mann's former business partner, split from the company last year, alleging financial mismanagement. And the company was forced to close its Oakland location last year.

So at least in its growing pains, weGrow is showing it is susceptible to the same problems as any other business.