At its freshest and best, garlic not only is a zestful seasoning but it's a healthy food, as well. It's our biggest vegetable import from China. At the White Dog Cafe in Philadelphia, chef Andrew Brown is using tender young garlic scapes from Green Meadow Farm in Gap while anticipating the July harvest of regular, red and elephant bulbs from Overbrook Herb Farm in Lansdale. The garlic used by chef Frank Maragos at Foti's, in Culpeper, Va., comes from nearby Campi di Sogni Farm, where owner Juliana De Santis grows about 30 kinds. But most of us buy garlic at...