Certified GKH Gardening Expert
Many wildflower seeds do best when planted in the fall. Do you have a seed packet that tells you when to plant? If not, wait till after the threat of frost is past, then plant in warm soil. They normally don't need to be covered, but in order to prevent birds from getting them, I would cover lightly.
Plant hostas in early spring or early fall. It's still a bit cold right now.