Not only are green beans a nice, crunchy, low-calorie food but also they provide many key nutrients. Young, tender green beans are a good source of vitamin C, dietary fiber, folate, vitamin K and silicon (needed for healthy bones, skin, and hair). They’re also easy to grow, with the added bonus of improving the soil they grow in because of their ability to “fix” nitrogen from the air in nodules attached to the bean roots. When the nodulated bean roots decompose, they liberate the nitrogen to become available for the next year’s crop planted in that spot. The leaves have three leaflets with a long petiole.