Harvesting Edible and Medicinal Weed Seeds in the fall is a good way to grow your own edible and medicinal weeds. These seeds are plentiful and grow without help, so imagine if you actually planted and tended to them? You can have a huge crop of edible weeds, or grow tons of medicinal weeds to make your own medicine. Without having to even leave your yard! This is like permaculture at its finest!