USDA Certified Organic foods and farms cannot use most synthetic or petroleum derived pesticides and fertilizers, any irradiation, or sewage sludge. No genetic engineering is allowed. Organic farmers use crop rotation, tilling and natural fertilizers, such as compost.
A USDA-accredited certifier verifies that a farmer or producer meets the standards of the USDA National Organic Program.
ecomii Green Dictionary A to Z. [online] Available from: http://www.ecomii.com/ecopedia/organic [accessed 16 December 2009]