I live in a place where it's cold half of the year, sometimes longer, but I want to do year-round gardening. My main question is what are plants that can be eaten and will still grow in cold weather. I'm also very interested in:

• plants that don't need a lot of help to grow indoors.
• plants that will grow on their own outdoors (even potentially through/under snow.

I'm also very interested in plants that have medicinal properties that persist in cold regions as well.