Herb garden in Michigan?

Recently moved into a home with an herb garden (many different ones - rosemary, dill, chives, basil, cilantro, and quite a few more that I am not sure what they are). Not sure how to properly care for it - any suggestions? I cut them all back and put some leaves over the top of it for winter as it was suggested. Do I fertilize in spring? If so- what to use that is safe and nontoxic? Thanks!