Legumes — beans, peas and non-edible relatives such as clovers — give back to your garden because they have a symbiotic relationship with a soil bacteria. This special relationship allows them to convert atmospheric nitrogen (N2) into ammonium nitrogen (NH4), which they release into the soil.

Do beans fix nitrogen?

Green beans are one of many plants that are well known for doing nitrogen fixation. And, they do this work in tiny bean-like nodules in their roots. However, there are many other plants that are called nitrogen fixers. For instance, all plants in the bean family do this.

How do beans fix nitrogen in the soil?

Legumes (peas, vetches, clovers, beans and others) grow in a symbiotic relationship with soil-dwelling bacteria. The bacteria take gaseous nitrogen from the air in the soil and feed this nitrogen to the legumes; in exchange the plant provides carbohydrates to the bacteria.