Heirloom tomatoes at the Walnut Creek Farmers' market in California. John Morgan / CC BY 2.0
By Tracy Matsue Loeffelholz
Sometime during the spring, backyard food growers decide what kind of tomatoes to grow: heirlooms or hybrids. Hybrid varieties have had the benefit of genetic tinkering that allows for some cool traits. But these seeds must be purchased new each year from the companies that create them.