Under Michigan law, as it currently stands, possession of marijuana is illegal unless an individual has a medical prescription and is a registered qualifying patient with medical marijuana card holder or registered caregiver with the State of Michigan, as permitted by the Michigan Medical Marijuana Act, M.C.L. §333.26421 et seq. Therefore, growing marijuana for your own use, without a medical marijuana patient card or a registered caregiver card is not permitted and doing so subjects you to potential criminal liability. While there is a very good chance that recreational possession and use may soon be legal in Michigan, if the November ballot initiative passes, for now the law is clear.
Source: Fowler & Williams
Michigan Commercial Grow License Application