MONTVILLE, Maine — Glenn W. Martin said he used to secretly grow marijuana plants among the deciduous and evergreen trees on his family farm, selling the illegal products in Boston and New York to help cover escalating property taxes and other expenses.
Now Martin, 34, cultivates the herb openly in a small greenhouse by his home. He is part of an expanding industry of farmers and other entrepreneurs seeking to profit from a Maine law that allows patients — with a doctor’s approval — to buy marijuana from small growers and nonprofit centers, as well as to cultivate their own.
“I’m focusing on how to make a high-quality product,’’ said Martin. He has also built a 7,000-square-foot barn to produce what he calls a “medicinal mix” of nutrient-rich compost to help marijuana plants flourish. “It’s one of the best things to happen in our area,’’ Martin said of the law, which until two years ago permitted use of the drug, but did not provide options for patients to obtain it legally.
Maine is one of 17 US states, including four in New England, that allow qualified patients with serious illnesses such as cancer to use marijuana to treat nausea and other conditions. State laws vary on how much cannabis a patient can possess and how they can legally obtain the drug.
A medical marijuana initiative — different in some ways from from Maine’s law — will be on Massachusetts ballots in November. It would allow up to 35 state-regulated, nonprofit centers to grow and sell marijuana to registered patients.
Maine, which first approved the use of marijuana for medical purposes in 1999, has the most developed program in New England.
There are about 780 registered growers, called “caregivers,” and eight shops, known as dispensaries, that cultivate and sell marijuana. The are about 2,700 people in the state’s patient registry. Participation in the registry is voluntary, which some say opens the system to abuse.
The Maine program is still being fine-tuned — regulations about growing marijuana outdoors are under consideration — but the state official in charge of the program said the law has helped reduce patient suffering while boosting a cottage industry of farmers and shops.
“It seems to be working,” said John Thiele, manager of Maine’s program. “It has not caused the downfall of Maine’s society.”
While marijuana is illegal under federal law, the US Department of Justice has said it does not target patients or caregivers who comply with state regulations governing medicinal use.
But law enforcement officials and some health care professionals worry the law is being abused in Maine, which already struggles with an epidemic of prescription drug abuse.
They say that since mandatory patient registration was repealed last year, there is no way to know how many people are getting marijuana through the program or growing it at home.
“Substance abuse is a huge issue in Maine and marijuana is right in the middle of that thing,’’ said Roy McKinney, director of the Maine Drug Enforcement Agency, part of the Department of Public Safety. “Now we don’t even know who the patients are.”
Maine’s original medical marijuana law did not include regulations governing how patients could get the drug. A law approved in 2009, along with amended regulations in 2010, authorized patients to grow it, buy it from a caregiver, or go to a dispensary.
Each caregiver is allowed to grow plants for up to five patients, as well as their own use, if they have permission from a doctor.
Those changes to the initial law have turned underground businesses into legitimate, tax-paying operations, and created much-needed jobs, advocates say. Small farmers are growing marijuana in greenhouses and elaborate indoor facilities, equipped with bright lights and fans, and Maine’s dispensaries have hundreds of regular customers.
The outlets sell marijuana in various forms — as an herb to be smoked, or in lozenges and baked goods. The $250 to $375 price per ounce is not covered by health insurance.
“This is a chance for people to stay in Maine,” said Paul McCarrier, legislative liaison for Medical Marijuana Caregivers of Maine, an Augusta organization that represents caregivers. “People are saying, ‘I can have a job here. I can pay for the fuel in my truck.’ ”
There is little data to show whether legalization of medical marijuana actually boosts local economies. But Harvard University economist Jeffrey Miron said his studies on marijuana decriminalization indicate governments may save modestly by reducing law enforcement efforts and gain revenues from taxes on income and sales.
“People who have been growing marijuana are still going to keep doing it, but now they will be officially counted as employed,’’ Miron said.
Caregivers must collect a 5 percent sales tax on the marijuana they sell and also pay income tax on their earnings. It is too soon to determine how much revenue has been generated for the state, Thiele said.
Martin is investing money in the marijuana business, part of a long-term effort to finance a lifestyle once supported by lumber sales. Marijuana sales still account for only about 15 percent of his family income — the rest comes from wood cutting and raising animals — but the extra money makes a big difference, he said.
Martin prides himself on living off his 500-acre farm, called Hogback Mountain. He and his wife are raising three children who do not expect a lamp to turn on with a switch or a toilet to flush.
The family lives in a small house where a hose provides the only running water, a kerosene lamp offers light, and the stove is fueled by wood.
“It’s a struggle,” he said of making a go of it in Maine.
McCarrier said a caregiver such as himself can launch a business with only a few thousand dollars. He said he earns about $600 a week growing marijuana at his home in Stockton Springs. He is also a patient, he said, but would not disclose his medical condition.
“It’s a way of life up here,’’ he said about growing marijuana. Now, McCarrier said, “You no longer have to be a pot dealer in hiding.”
In nearby Washington, Jake McClure, 33, runs a consulting business for marijuana entrepreneurs. He also has rigged his farmhouse to be a self-contained farm, growing plants in a former in-law apartment as well as an enclosed back room, using a complex set of high-intensity lights, fans, dehumidifiers and air conditioners.
McClure expects to earn about $65,000 after expenses this year between his two marijuana-related businesses. It’s a decent income for a guy without a college degree, he said.
“There’s just a humongous explosion of money and economic development going on here,’’ he said. “We have people who are making comfortable livings now, and they are used to being on welfare.”
All eight Maine dispensaries opened within the last two years. They generally charge higher prices than individual growers, between $325 to $375 an ounce, but are considered more convenient by some patients.
Becky Dekeuster, executive director of the nonprofit Portland-based Wellness Connection of Maine, which runs four of the dispensaries, said marijuana helps seriously ill people fight pain, stimulate appetite, and reduce nausea. As a bonus, she said, dispensaries also have put people to work.
“The job market is tough. These are jobs at good wages with good benefits and the added benefit of the ability to do what’s right for people who are sick,’’ Dekeuster said.
Increasingly, states are looking to dispensaries as the primary way to get marijuana to patients. In June, Connecticut approved a medical marijuana law that would rely on dispensaries for distribution. Rhode Island and Vermont are in the process of changing existing regulations to allow for dispensaries similar to those in Maine.
The Massachusetts measure also focuses on opening dispensaries, but would allow some patients to grow their own marijuana.
Whitney A. Taylor, a spokeswoman for the nonprofit Committee for Compassionate Medicine — which is lobbying for the Massachusetts initiative — said the Bay State’s proposed law was written to incorporate “best practices” from other states.
“This is not going to be somebody ‘s uncle or cousin out in the field trying to figure out what to do with someone’s medicine,’’ Taylor said. “The reality is growing medical marijuana is not easy.’’
Opponents of the Massachusetts initiative, including the nonprofit physicians’ organization, the Massachusetts Medical Society, say there is not enough scientific research to show marijuana use is safe and effective.
Heidi Heilman, president of the Massachusetts Prevention Alliance, an Acton group opposing the ballot question, called it a “ploy” to allow “pot shops.”
“This would increase widespread use and abuse in Massachusetts,” she said. “It’s another industry like tobacco and alcohol that hook their consumers early.”
In Maine, however, medical marijuana initiatives have won the support of voters on two occasions. Thiele said Maine’s experience stands out because federal law enforcement officials haven’t swooped in to raid dispensaries, which has happened in California and other states.
Tight state regulations, a limited number of dispensaries, and a Yankee culture that frowns upon pot smoking in public have given medical marijuana a relatively low profile in Maine, according to Thiele, the program’s manager.
“So far, knock on wood, we haven’t had the type of inflammatory conflict that would draw the feds to the state,’’ he said.
Jenifer B. McKim can be reached at firstname.lastname@example.org. Follow her on twitter @jbmckim.