Sunflower seeds usually are left on the flower to dry. The flower may have to be wrapped with cheesecloth to prevent the birds from eating the seeds.
Seeds may be dried in the sun or in a dehydrator at 100ºF. Higher temperature affects the flavor.
When seeds are dried, they can be roasted in a shallow pan at 300ºF for 10 to 15 minutes.
This document was extracted from "So Easy to Preserve", 5th ed. 2006. Bulletin 989, Cooperative Extension Service, The University of Georgia, Athens. Revised by Elizabeth L. Andress. Ph.D. and Judy A. Harrison, Ph.D., Extension Foods Specialists.