Long ago, before the advent of agribusiness and genetic engineering, tomato cultivars were passed down from generation to generation, like precious family heirlooms -- hence the name "heirloom tomato." For a relatively small investment, you can grow your own heirloom tomatoes from seeds or seedlings. They don't look like the tomatoes you'll find at the grocery store, but you'll notice the difference when you bite down. There's nothing like a fresh heirloom tomato.