Agriculture has changed dramatically since the end of World War II. As a result of new technologies, mechanization, increased chemical use, specialization, and government policies, food and fiber productivity has soared. While some of these changes have led to positive effects, there have been significant costs: topsoil depletion, groundwater contamination, harmful pesticide residue, the decline of family farms, and increasing costs of production.To counterbalance these costs, there is a growing movement to grow plants organically.

On a local level, suburban homeowners and city dwellers are finding ways to plant their own food for personal consumption in plots that are...