I'm not much help for vegetables, but just saw a quick/easy way to harvest purple cone flower seeds. Cut the dry seed heads off (preferably before the birds get them...if they haven't already! Then, if you've got an empty coffee can or similar sized container (I'm using an HEB plastic leftover container, large-ish), put 4-5 seed heads into the container, put the lid on, and shake vigorously for a bit to dislodge the seeds. Remove the spent seed heads, and continue shaking your harvested seed heads in batches. Et voila! You should have a nice pile of seeds left in the bottom.
