Lecture by Watertown resident and author Peter Del Tredici, on how healthy soil impacts your garden. Free and open to public.  Seed swap follows discussion, so please bring seeds you've saved from your own garden, or extra seeds from seed packets that you've bought. If your seeds are more than 2 years old, please mark the approximate year on the package. We will have seed envelopes on hand if you would like to divide larger packages of seeds.