Narrator: This is Science Today. Farmers, advisors and many consumers are often looking for accurate information about the production and marketing of organic produce, which has become the fastest growing segment of agriculture. Julie Guthman, an assistant professor in community services at the University of California, Santa Cruz, says the basic definition of organically grown is that a crop can't be grown with a material that's not allowed.

Guthman: What's not allowed is the result of a long history of debate within the organic farming movement of what the standards should be.

Narrator: The first organic standards in California were written on half a page in a newsletter insert and were very much focused on a set of processes. Now, Guthman says the standards are written in an inch-thin book.

Guthman: But the basic information is that a material is not allowed to be used in organic farming if it's synthetically produced, that organic farming should be more process oriented, pay more attention to the use of biological pest controls and composting and cover cropping.

Narrator: For Science Today, I'm Larissa Branin.