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Seed resources and useful seed websites
Seed identification
International Seed Morphology Association
The International Seed Morphology Association provides a Seed Identification Guide (SIG)®, author resources that include illustrations of seed shapes, textures, and embryoEmbryo: A rudimentary plant contained in a seed, usually consisting of a more or less differentiated axis and attached cotyledon(s). types, as well as a secured area featuring seed identification quizzes and a forum for peer support and knowledge sharing.
USDA PLANTS Database PLANTS Database provides standardized information about the plants of the United States and its territories. It includes names, distributional data, characteristics, images, and crop information.
Germination - Wikipedia A great overview of the germinationGermination: The resumption of active growth by the embryo culminating in the development of a young plant from seed. process.
Seed and Seedling Biology An overview of seed development, germinationGermination: The resumption of active growth by the embryo culminating in the development of a young plant from seed. , and dormancy focused on crops.
Tom Clothier's Garden Walk and Talk Gateway to the indexes for seed germinationGermination: The resumption of active growth by the embryo culminating in the development of a young plant from seed. databases, garden FAQs, articles on gardening strategy and technique, pest control strategies, photo library, and how-to-do-it sections.
Seed dormancy
The Seed Biology Place Dr. Leubner's seed biology lab website includes information on seed germinationGermination: The resumption of active growth by the embryo culminating in the development of a young plant from seed. , dormancy, after-ripeningAfter-ripening: A term for the collective changes that occur in a dormant seed that make it capable of germination. It is usually considered to denote physiological changes. , and more.
SeedQuest Technology SeedQuest's page on laboratories offering seed analysis and seed testing services.
Tetrazolium testing
Tetrazolium testing for flower seeds, USDA-ARS A book chapter on history and methods of tetrazoliumTetrazolium: Indicates a class of chemicals that have the ability to accept hydrogen atoms (and undergo reduction) from dehydrogenase enzymes associated with living tissue. When this reduction occurs, the tetrazolium (TZ) chemical undergoes a change, usually from colorless to red. testing for seed viabilityViability: Alive. Seed that has the ability to grow containing structures and substances including enzyme systems that give it germination potential. . USDA-ARS publication.
Understanding the Tetrazolium Test in Seed Analysis Overview of tetrazoliumTetrazolium: Indicates a class of chemicals that have the ability to accept hydrogen atoms (and undergo reduction) from dehydrogenase enzymes associated with living tissue. When this reduction occurs, the tetrazolium (TZ) chemical undergoes a change, usually from colorless to red. testing by International network for seed-based restoration.
Plants Human Affairs: Seed Viability A school classroom exercise in tetrazoliumTetrazolium: Indicates a class of chemicals that have the ability to accept hydrogen atoms (and undergo reduction) from dehydrogenase enzymes associated with living tissue. When this reduction occurs, the tetrazolium (TZ) chemical undergoes a change, usually from colorless to red. testing. Full lesson plan details for schools.
Seed regulatory, certification, and seed testing organizations
Analyzeseeds: AOSA and SCST Association of Official Seed Analysts's website with information on seed testing. For an updated list of seeds included on the exam, see Consolidated Exam Comittee page, open Consolidate Exam Content & Preparation tab for Seed Identification List spreadsheet.
USDA Federal Seed Act USDA Agricultural Marketing Service overview of federal seed act, filing a complaint, variety names, and more.
USDA State Noxious-Weed Seed List, revised Feb 2026 USDA Agricultural Marketing Service state noxious-weed seedWeed seed: A seed from a plant generally considered undesirable. The total percentage (by weight) of seed lot that is composed of seed of plants considered to be weeds. One of the four components of purity test. requirements recognized in the administration of the federal seed act.
types, as well as a secured area featuring seed identification quizzes and a forum for peer support and knowledge sharing.