At left, a woman holds the saffron crocus during the saffron harvest in Herat, Afghanistan. At right, saffron flowers are collected in Saint Hippolyte, eastern France. Since the stigmas need to be picked from the flowers by hand, saffron is the world's most expensive spice. Majid Saeedi/Getty Images; Maxppp /Landov hide caption

itoggle caption Majid Saeedi/Getty Images; Maxppp /Landov

Wheat fields like this one could yield wheat with less zinc and iron in the future if they are exposed to higher levels of CO2, according to the journal Nature. Zaharov Evgeniy/iStockphoto.com hide caption

itoggle caption Zaharov Evgeniy/iStockphoto.com

Rowbot is designed to fit in between the rows of crops. Moving up and down each row, a fleet of 20 bots could fertilize and monitor the corn crops during the growing season. Courtesy of Kent Cavender-Bares hide caption

itoggle caption Courtesy of Kent Cavender-Bares

The seed library is a partnership between the Basalt Public Library and the Central Rocky Mountain Permaculture Institute. Seed packets encourage gardeners to write their names and take credit for their harvested seeds. Courtesy of Dylan Johns hide caption

itoggle caption Courtesy of Dylan Johns