What makes an heirloom an heirloom? What makes an heirloom tomato, an heirloom is the seeds. Each year seeds are taken from the best producing, tasting, or looking plants and passed down to grow in following season. These plants are open pollinated and usually have fun and stories and history that has been passed down with them. With unique flavors and colors, heirloom tomatoes are truly something special. At Sprouts, we like to encourage you to explore these fun varieties and carry a great selection of heirlooms for you to choose from.