Purple Clover - Green Manure

The violet clover, in Latin Trifolium pratense, is a small perennial of the legume family that is used as a green fertilizer for several years or as a forage plant. Its roots have the ability to fix atmospheric nitrogen, which it will return to the soil, thus reducing the need for fertilizer. It is also a honey plant, with dark pink flowers rich in nectar that feed pollinating insects. Through its root system, it loosens the soil, limits the proliferation of unwanted weeds, and combats soil leaching or compaction caused by rain. It is sown from March to August.

The violet clover belongs to the Fabaceae family (formerly legumes) and the genus Trifolium like white clover or Alexandrine clover. These different clovers are characterized by their leaves with 3 leaflets and their ability to fix atmospheric nitrogen in the soil. The violet clover has good frost resistance and develops a significant vegetative cover. During the summer, it blooms in the form of spherical heads of dark pink color. The violet clover is suitable for all types of soils.

Widely used in organically cultivated gardens, green fertilizers like violet clover have many advantages. They feed and improve the soil by providing it with various nutrients and stimulating the soil's microbial life. Their roots will loosen, break up, and aerate the soil. Moreover, the presence of a vegetative 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 steep terrain during heavy rain). This vegetative cover also helps limit weed growth by preventing the growth of unwanted weeds. Finally, green fertilizers are often honey plants and attract pollinators.

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