Dirty Dozen is an ongoing Organic Nation series that seeks to explain the benefits of certain organic foods and products over their conventional counterparts. To see other recent posts in this series, click here.

When the Environmental Working Group released their latest wallet-size "Dirty Dozen and Clean 15" scorecard last spring, kale, the most crinkly of the hearty greens, was catapulted into eighth place on the list of conventional fruits and veggies to be avoided.

Kale is tasty and nutritious stuff, and it's great in salads, soups, or even just sauteed with onions and olive oil. The other neat thing about kale is that it can survive year-round -- even in deep snow. When I visited my parents near Buffalo, NY last month, my mom went out and picked some fresh kale from beneath a six-inch layer of snow for our dinner.

However, according to EWG, it's one of the foods that should always be grown organically.

It's surprising to see that kale is sprayed with so many chemicals, because it seems like such an easy plant to grow. Because of it's heartiness, kale is great for gardens, but it can attract some pretty pesky pests when it's grown on a larger scale in an agricultural setting. Aphids, diamondback moths, and flea beetles are all considered to be major pests to kale.

The EWG's list isn't based on the total amount of chemicals sprayed on fruits and vegetables in the field or on the vine. Instead, most of the data they use to compile the "Dirty Dozen" list comes from tests taken from foods that are ready to be eaten. According to the website, "nearly all the studies used to create the list test produce after it has been rinsed or peeled."

In addition to EWG's scorecard the new website whatsonmyfood.org gives conventional kale very low marks. According to that site, conventional kale contains 49 pesticide residues found by the USDA pesticide data program. Those chemicals include two dozen possible hormone disruptors, 10 neurotoxins, and seven known or probable carcinogens. Yummy!

-Mark