Heirloom strawberries are smaller than modern varieties. Robin Chotzinoff, columnist with Food & Wine magazine, suggests that you can tell an heirloom from a modern strawberry by closing your eyes and sniffing. Heirloom varieties have a stronger scent.
There are many heirloom varieties but not all are available. Look for Sparkle, Ozark Beauty, White Carolina and Hautbois, a musk strawberry.
Look for heirloom strawberry varieties in seed catalogs that sell gourmet food seeds. You might ask at your favorite nursery if they know of a local source of heirloom strawberry seed. You can also purchase the seed online at retailers such as Fraises des Bois, The Strawberry Store and Heirloom Organics.