At night you would need either supplemental heat or massive passive heat storage to supply the heat, like drums of water. Without heat, the greenhouse would get almost as cold as the outside temperature, and that would wipe out any crops you had growing. Given how cold Michigan can get, you might need heat during the day as well. I don't live in the Midwest anymore, and have never tried this, but what you would like to do might not be a very economical way to produce vegetables given the cost to heat the greenhouse.

In-ground, if you can do it, is better than containers in winter.
Select only hardy greens to grow, like mache, claytonia, spinach, kale and collards.
Starting seed in winter will not work. Light levels are too low. However, fall-started seed (start ASAP) will continue to grow, at a very slow rate, if you use only hardy crops and protect them additionally with row covers.

If you are interested in all this, check out Eliot Coleman and how he does it in Maine.

I second the recommendation for Eliot Coleman's books. I think Winter Harvest gives more detailed information about each vegetable variety they grow and the critical timing. He does not heat his greenhouses but uses a system of high hoops and low tunnels. The low, fabric covered tunnels give additional protection.

The current issue of Mother Earth News has some hoop house building instructions. Cost around $1,000 DIY. We are planning to build one next year.

Understand that there will be little growth during the short days of winter. I heard people at the NOFA spring conference in NH talk about when you had to sow in order to get some growth before the short days.

This year we started out with a single fabric covered low tunnel that would cover one bed. I planted a row of beans, a row of kale and a row of summer turnips in early May. The beans did fine despite a cold, wet spring. I heard other gardeners complain that their seed just rotted.

Meanwhile, on Facebook our daughter-in-law's uncle was setting out his plants that he had started indoors. They were eating zucchini in June. He uses a system of plastic covered low tunnels.

We recently put the fabric tunnel back into use to protect a late planted double row of string beans when temps got into the high 30s F at night. This past week it got hot and humid so we took the tunnel off. I was worried about air circulation/rust and pollination. The plants were in full bloom by mid-Sept. It looks like we have a nice batch of new yellow beans for supper tonight 9/26. It's going to get cold again by the end of the week. We'll watch the forecast and put the tunnel back on. We left some steel fence posts that held the pea fencing in the ground otherwise I probably could have tipped the tunnel off by myself. The bottom is a wood frame so the frame holds the hoops instead of putting the hoops into the ground.

My plan is to start seed indoors where it is warmer and then put heat loving plants out under plastic low tunnels although I'm debating about fabric which doesn't need ventilation if it gets hot. But, I have the heaviest weight of Agribon. It was great for protecting our strawberry harvest from birds but in July it was too hot on young blueberry bushes.

I've been debating the costs. Greenhouse plastic will need to be replaced about every 4 years. We will probably keep things simple and affordable but it will be "season extending" techniques for cool weather vegetables. We won't try to have tomatoes in January.

kawaiineko_gardener: This winter will be my third year of experimenting with Winter gardening. I am in Massachusetts, Z5. My GH is a bit different so your results may vary. Here's what I find...

I plant beets in late november and can havest them in march or April. Spinnach is one crop that i can harvest through January, thoug it does slow down. I consider that successfully gardening through Winter.

I've played with a variety of plants and am willing to say that anything that stays green until the first frost outside is a candidate for winter growing.

There are likely exceptions, for example, I won't try any cole crop again as my GH uses a double plastic layer and they just don't do well with the reduced light (Even in summer).

My biggest issue is humidity. It rains in the greenhouse.
Even though my tomatoes survive into december, the high humidity makes them rot and mouldy. I have no power in the GH, so no fans.

This week i'll plant cukes, summer squash, carrots, beets, lettuce, chard, spinnach, raddishes and peas. The squash and cukes are experiments to see if i get something off them before they succumb to the cold. The rest should do well.

Poppa