Buy local is the biggest crock (with one exception: if you honestly and truly believe the food is better quality). It causes a net loss for society. Consumers can't purchase as many goods, and the goods being purchased are not being produced as efficiently as the 'non-locals' version. Which means your groceries cost more every week then they would have otherwise.
http://mises.org/daily/5283/The-BuyLocal-Canard