I have. Mostly Field, Winter, or Cereal Rye with some Vetch, sometimes clover and/or oats if the bed is to be fallow for the growing season. Mulch mowing them, before they set seed, or tilling them in is a good method of adding organic matter to the soil and aiding in suppressing unwanted plant growth.

Peaceful Valley Farm Supply in Northern California has lots of information about cover crops and you can order from them as well.

I have ordered from them in the past with no problems.

Ginny

Here is a link that might be useful: Peaceful Valley -Cover Crops

For a home garden, I recommend a clover for the nitrogen fixation. I know you are in a different zone than I, but there are some clovers (crimson clover here) that are much more tender, don't get weedy, and are easily just chopped up, hoed away, sheet mulched, and/or overplanted.

A slightly more adventurous approach: I use a tough perennial white clover cover. Chop and drop the clover where it gets too big and/or cardboard sheet mulch around the root zones of weak plants (eg vegetables). The decaying clover shoots/roots under cardboard are good soil-builder. This also suggests a system that increasingly incorporates more fruit/nut trees, berries, herbs, tubers, and other tough ecosystem-building perennial food-plants.

I've also heard buckwheat is a good soil builder, and easy to progress out of, but I don't have as much experience using it.

-B

I have tillage radishes growing now. They winter kill and crowd out weeds pretty well as they take off quickly. They need to be planted here by about September 5....so too late for you this year.

Your county horticulturist at the Michigan State University
Cooperative Extension Service office would be of much help in determining which cover crop does best in the northern lower peninsula of Michigan.

Here is a link that might be useful: MSU CES

Oats (some types -- be sure it's a type that winter kills) has worked well for me -- can plant now and generally winter kills in zone 5. No tilling necessary, just rake to the side to plant in spring.

The radishes are the easiest of about all cover crops. They disentigrate by themselves in winter/spring and quickly deep root themselves.

I'm experimenting this winter in one of my beds with some beans. Great Northern beans, to be exact. I hear that beans fix nitrogen? They were cheap, and I had an empty spot in the garden, so i figured...why not?

I'm expecting them to grow for a few more weeks and die back with the first frost.

I purchased a bag of deer plot seed from Walmart on sale. It was a blend of oats, rape and peas. The deer plot is designed to be used in fall and has done well . Throughout spring and summer Marigolds or buckwheat are my favorite choices though bc of beneficial insects they attract. I've grown a array of seeds as green manure, and try new types of blends every year.