At 12:01 a.m. Thursday, Michigan turned green and became the 10th state in the nation to legalize marijuana for adult recreational use.

But the old saying, "Smoke 'em if you got 'em," carries many, many caveats.

Matt Abel, who has been a marijuana advocate for years and is the executive director of the Michigan chapter of the National Organization for the Reform of Marijuana Laws, said he planned to "roll a big fattie and smoke it at midnight," when Michigan's voter-approved ballot initiative on recreational marijuana officially went into effect.

"This is the last day of prohibition," he said on Wednesday. "It's significant and a milestone for marijuana laws in Michigan. But we still have a ways to go."

Indeed, when he smokes that big marijuana joint, he'll need to be inside his house or other private residence because indulging in marijuana in public will remain illegal.

And that means no firing up a bowl on the front porch or vapes in the driveway because those are considered public places, said Royal Oak cannabis attorney Barton Morris.

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"Anything that’s publicly accessible to people is out of bounds," he said. "It's customary for people to come up on your front porch or walk up your driveway."

Your backyard should be okay, said Doug Mains, an attorney who represents medical marijuana clients with the Honigman law firm in Lansing

"Is your backyard a public place? Probably not, since nobody can really walk into your backyard whenever they want," he said. "That is probably even more so if your yard is fenced in or you are far away from your neighbors."

But there is still the matter of the pungent aroma of marijuana, said Morris, which may cause neighbors to lodge a nuisance complaint.

"A next door neighbor shouldn’t be able to smell it," he said. "Everyone has the ability to the quiet enjoyment of their property."

A grow operation in a residential home in Sterling Heights, for example, was shut down this summer after neighbors complained of the noxious odors coming from the house.

So the free and easy reputation of legal weed? Not so much.

Now that it's legal, here's what you need to know about marijuana:

Where can I buy marijuana?

Marijuana won't be commercially available for sale until state regulators draft rules and regulations for the recreational market. They have until December 2019 and then they can begin to accept applications for licenses, with the first commercial retail sales expected in 2020. After the medical marijuana industry was regulated in December 2016, the first licenses weren't awarded until August 2018.

In the meantime, people can grow up to 12 plants in their homes for personal use and they can give — but not sell — the product to friends and family. That may change if Senate Majority Leader Arlan Meekhof, R-West Olive, has his way. He has introduced a bill that would ban people from growing their own marijuana, but it will need a super-majority — a three-fourths vote — to pass, which will be a difficult to accomplish.

Where can I get the seeds or marijuana plants to begin growing?

Seeds and plants are available for sale online, but since the federal government still considers marijuana an illegal drug, it's also illegal to ship it across state lines. The registered caregiver market, in which a person can register to grow up to 72 plants for medical marijuana cardholders, will stay in place even after the recreational market gets up and running and seeds and plants could be available from them.

More: Finding seeds to grow marijuana at home in Michigan will be hard

Marijuana is legal in Canada. Can I buy it there?

No. It's still considered an illegal drug by the federal government, which has control of the border with Canada, so it can't be transported across state lines or across the Canadian border.

Is there an age requirement? Or limits on pot possession?

Yes, you have to be 21 to indulge in Michigan. And once marijuana becomes commercially available, people can buy and possess and carry 2.5 ounces of pot a day, and can keep up to 10 ounces in their home as long as it's locked up. Police will no longer be able to arrest people for use or possession of small amounts of marijuana.

What health effects will marijuana have on me or those around whom I smoke?

A 2014 study published in the medical journal Current Opinion in Pulmonary Medicine said that a person heavily smoking marijuana could be more susceptible to chronic bronchitis.

In Canada, which legalized marijuana for recreational use on Oct. 17, Health Canada, the nation's health ministry, launched a campaign to educate the public about the dangers of cannabis use. The message is that young people should avoid it. "We know that the brain is still undergoing significant maturation until the age of 25," said Dr. Amy Porath, director of research for the Canadian Center on Substance Use and Addiction. "To preserve brain health, it's important for young people to delay the use of cannabis as long as possible."

It is not clear whether a human being exposed to second-hand marijuana smoke would suffer the same effects as those exposed to cigarette smoke. The National Institute on Drug Abuse said in a June 2018 report that little research has been done on the subject.

Will marijuana help relieve ailments?

Few people dispute the medical benefits of marijuana on a variety of ailments, including chronic pain, seizures, cancer, glaucoma and PTSD. And the state has designated 22 conditions, including Parkinson's disease, Tourette's syndrome, epilepsy and arthritis as qualifiers for medical marijuana cards.

In states that have legalized marijuana, opioid prescription drug use declined by 2.3 million doses in 2017, according to a study published in the Journal of the American Medical Association.

What about smoking and driving?

It's illegal. Michigan has a zero-tolerance policy for drugged driving. So any amount of THC — the psychoactive component in marijuana — in a driver's blood is illegal and can be criminally charged, just like a drunken drunk driving offense.

It will be more difficult to test for marijuana in the system, however, and will be done either by a blood draw or possibly by oral swabs if a pilot project recently completed by Michigan State Police proves successful.

What about marijuana in the workplace?

Employers can keep and enforce zero tolerance policies for their workers. The law doesn't change a business owner's ability to perform pre-employment or random drug tests on workers and refuse to hire, or to fire or discipline workers who test positive for marijuana. Some "safety sensitive" businesses such as utilities, trucking companies, manufacturers and hospitals maintain a zero tolerance policy as well as companies that have federal contracts because the feds still consider marijuana an illegal drug.

More: Michigan employers still can fire you for smoking pot

How long will marijuana stay in your system?

Part of the problem for employers and their workers is that unlike alcohol, where tests can show the exact level in a person’s blood, there are few available tests that show the level of impairment for marijuana. Saliva swabs and urine samples only show if THC, the psychoactive component in marijuana, has been used over the last few days, said Dr. Barry Sample of Quest Diagnostics, a New Jersey company that analyzes millions of workplace drug tests every year. Swabs and samples don't show a person’s level of impairment at the time of a test. Tests of hair samples will show THC levels going back as long as 90 days.

What about marijuana businesses in cities?

At least 28 communities across the state, including Birmingham, Royal Oak, Fraser, Livonia, the village of Pinckney and Plymouth, have decided to ban recreational marijuana businesses from their communities. Each town has to determine whether it wants to allow and regulate or prohibit marijuana businesses. Approximately 108 communities, including Detroit, Warren, Hazel Park, Walled Lake, Orion Township, Harrison Township, Lenox Township, Garden City, River Rouge and Inkster, have already adopted ordinances to allow medical marijuana businesses in their communities

Does the new law affect Michigan's medical marijuana laws?

No. Caregivers still can grow up to 12 plants for each of five medical marijuana card holders. The only difference for cardholders will be that a 3 percent excise tax on medical marijuana sales at dispensaries will go away in early 2019.

What about marijuana convictions?

It will be up to the state Legislature to pass a law that would work toward expunging the records of people convicted of low-level marijuana crimes. And four bills trying to achieve that goal have been introduced in the Legislature, although none has been scheduled for a hearing.

Gov.-elect Gretchen Whitmer, an East Lansing Democrat who will take office on Jan. 1, also has said that she favors clearing up the records of people convicted of crimes that will no longer be offenses under the legalization of marijuana.

Kathleen Gray covers the marijuana industry for the Detroit Free Press. Contact her: 313-223-4430, kgray99@freepress.com or on Twitter @michpoligal. To read more on the marijuana industry and its potential impact in Michigan, go to freep.com/news/marijuana