There’s a lot of interest in growing medical marijuana in Minnesota.

Whether that interest will translate into applications to become one of two state-registered growers is another question — particularly since there’s a $20,000 nonrefundable application fee.

On Friday, state officials tested the waters with a forum in St. Paul for potential applicants. More than 100 showed up, although some sounded skeptical about the state’s new program.

“It seems like it is going to be very hard to make this work,” Ben Streit of Duluth said during a question-and-answer session. “What if no one applies?”

“That would be a very bad outcome,” replied Manny Munson-Regala, assistant commissioner at the Minnesota Department of Health. “I go on an hourly basis from thinking we’ll have zero applications to thinking we’ll have 62.”

The meeting Friday at the Minnesota History Center was the latest step in implementing Minnesota’s medical marijuana law, which Gov. Mark Dayton signed earlier this year.

Minnesota is one of 21 states plus the District of Columbia that has passed a law for medical marijuana programs. Two of those states also allow recreational use of marijuana, while another 11 states provide more limited access.

The law will allow patients in Minnesota to obtain medical marijuana in pill or liquid form if they had one of eight qualifying conditions such as cancer, glaucoma or seizures. Marijuana also could be available to patients with terminal illnesses and a life expectancy of less than a year.

“We have some really sick people in our state who aren’t being aided by our medical structure today,” Munson-Regala said. “Medical cannabis has the potential to fill some of the gaps.”

For the program to work, manufacturers must come forward and be willing to pay not just the application fee, but also invest in facilities for growing marijuana and turning it into medicine. Each manufacturer that’s selected by the state also must operate four distribution centers — one center located in each of the state’s eight Congressional districts.

Start-up capital requirements could run in the neighborhood of $10 million, said Eric Reichwald, an attendee at Friday’s event who said he did lobbying at the Legislature this spring in support of the medical marijuana law. Reichwald said he hopes to work with a Colorado company to help test the quality of marijuana grown by manufacturers here.

Keeping facilities secure is one of the big expenses for manufacturers, Reichwald said.

Streit said he is working with a group that’s considering an application to become a manufacturer. He agreed that start-up costs could run in the neighborhood of $10 million and said the high costs explain why some are frustrated with Minnesota’s program. The Legislature opted against medical marijuana available for patients with intractable pain — a diagnosis that would have broadened the market.

Currently, the state expects about 5,000 people per year to use medical marijuana, although some industry sources had suggested the actual figure could be closer to 15,000, said Munson- Regala, the Health Department official. In an interview, he said he wasn’t sure exactly how much manufacturers would need for start-up costs.

The $20,000 application fee is high, Munson-Regala agreed, but he said the funds will help cover the cost of making sure that applicants have the experience and resources to produce high-quality products.

Anyone interested in applying to become a manufacturer must signal intent to apply by Sept. 19. Semi-finalists would be named by late October, and the final two manufacturers registered by Dec. 1. Manufacturers would begin providing medical marijuana to patients from at least one distribution center by July 1, 2015; all four centers would need to be operating a year later.

Minnesota’s medical marijuana law does not let patients smoke the drug. Physicians would certify that patients have a qualifying medical condition and contribute information to registry for tracking patient outcomes.

Christopher Snowbeck can be reached at 651-228-5479. Follow him at www.twitter.com/chrissnowbeck.