Onobrychis viciifolia - seeds

Cultivated Sainfoin or Onobrychis viciifolia is a perennial legume that grows to about 80 cm tall, grown as a forage plant and a green manure. Like all legumes, it can fix atmospheric nitrogen in the soil while protecting it from rain leaching. Sainfoin is known for its good hardiness (-10°C) and is particularly well-suited to shallow, chalky, and dry soils. Sow from March to late April.

Cultivated sainfoin or Onobrychis viciifolia, is a herbaceous plant in the Fabaceae family. It is an upright plant with pinnate leaves, with 6 to 14 pairs of oblong to linear leaflets. The flowers appear in the axils of the upper leaves in long pendulous clusters. They are pink, marked with purple veins. The fruits are small toothed pods. Sainfoin has a strong root system. The plant measures 50 to 70 cm high.

Green manures like cultivated flax are widely used in organically cultivated gardens and have many advantages. They nourish and improve the soil by providing it with various nutrients and stimulating the soil's microbial life. Their roots will loosen the soil, break up compacted areas, and improve aeration. Additionally, the presence of a vegetative cover protects the soil from leaching (nutrient loss in sandy soil), rain compaction (crusting in loamy soil), and erosion (caused by runoff on sloping terrain during heavy rain). This vegetative cover also helps control weed growth. Finally, green manures are often nectar-rich and attract pollinators.

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

A gardener's tip: just like with vegetable crops, it is important to consider rotations for green manures: don't always sow the same ones in the same place!