Vetches are plant species belonging to the genus Vicia and the Fabaceae family. Like all legumes, vetches associate with rhizobium bacteria to fix nitrogen in the soil. This mechanism supports plant growth, as well as that of other nearby species, without the need for fertilizers. They also provide excellent cover and improve soil structure. Mainly used as green manure in vegetable gardens, vetches are annual plants with climbing stems and purple, pink or white flowers. Sown from spring to autumn, depending on the species, they are then mowed 3 months later and left to mulch or incorporated into the soil.