Buckwheat - Green manure

The Buckwheat, in Latin Fagopyrum esculentum, commonly known as Black Wheat, is an annual plant known as a 'cleansing' plant that is used as a green manure to improve the soil in the vegetable garden, between two crops. It is known to attract beneficial insects, limit the growth of unwanted weeds, contribute to soil loosening while combating soil leaching or the phenomenon of compaction linked to rain. Buckwheat is sown in spring after frost, until August. It is mowed from April to July or from August to October, and the waste is buried from May to August or in October-November.

Buckwheat belongs to the family Polygonaceae and not to the wheat family (Triticum) despite its name of black wheat. It is used as a green manure, particularly for its 'cleansing' properties with regards to unwanted weeds and its strong covering power. Buckwheat develops upright stems of 30 to 70 cm (27.6 in) in height, with a purple color. The leaves are heart-shaped while the small flowers, white-pink in color, are clustered tightly. Buckwheat is sensitive to frost. It thrives in all types of soils, including poor soils.

Widely used in organically cultivated gardens, green manures like buckwheat have many advantages. They nourish and cleanse the soil by providing it with various nutrients and stimulating the soil's microbial life. Their very dense roots will loosen, break up and aerate the soil. Additionally, the presence of a vegetation cover protects the soil from leaching (nutrient loss in sandy soil), rain compaction (formation of a crust in loamy soil), and erosion (caused by runoff in case of heavy rain combined with a sloping terrain). This vegetation cover also helps to limit weed growth by preventing the germination and development of unwanted weeds. Finally, green manures are often nectar-producing and attract pollinators.

Green manures are sown on uncultivated plots or on intercalary plots, between vegetable rows. They are destroyed either naturally by frost, or by mowing before seed formation. Once destroyed, they can be left in place as mulch, or be crushed and incorporated into the surface layers of the soil, or be collected and added to compost.