There are several ways to preserve the goodness of calendula blossoms. Drying the blossoms is the easiest way, but dried flowers will preserve the goodness of calendula for only a year. By preserving it in other ways, you can extend this shelf life
Remember Hugulkultur in creating raised beds. Since I like the higher beds, filling the bottom half with prunings and such will reduce amount of topsoil needed to fill bed.