My herb garden, buried under several inches of packed snow, holds all the promise of spring, and so do the seed catalogs that begin to fill my mailbox. One of my favorite companies, Seeds of Change, sells 100% organic vegetable, herb and flower seeds. Through their donation program, Sowing Millions, they offer premium seeds at very low cost to nonprofit community gardens. By shopping through the Seeds of Change catalog, we help make those donations possible. If you buy seeds by mail, what are your favorite catalogs/sources?