Q: When should I buy organic, and when should I not worry about it? 

A: The Environmental Working Group lists the “Dirty Dozen”, the top twelve produce items that carry the most pesticides. These are the ones to splurge on when you have the opportunity to buy organic: 

Peaches, apples, sweet bell peppers, celery, nectarines, strawberries, cherries, pears, grapes (imported), spinach, lettuce, potatoes. (source: www.ewg.org)