Sowing green manure: benefits, types, planting schedule

Green manures: what are they?

Green manures are plants that are sown not to be harvested, but to nourish, protect, and structure the soil. Once sown, they grow quickly, cover the ground, and are then mowed or buried to enrich the soil.

They are a pillar of permaculture and sustainable gardening, as they help to avoid chemical fertilizers, improve fertility, and limit erosion.

1. Why sow green manures?

• Structure the soil thanks to strong roots that loosen without digging.
• Fix atmospheric nitrogen (plants from the Fabaceae family).
• Limit weeds by a dense cover effect.
• Protect bare soil from frost, drying out, or crusting.
• Promote microbial life by adding organic matter.

2. What types of green manures to choose?

🌿 Phacelia

• Fast growing, melliferous (attracts pollinators).
• Not part of cultivated families: low risk of imbalance.
• Sow from March to October, grows in 6 to 8 weeks.

🌱 Crimson clover or dwarf white clover

• Powerful nitrogen fixer.
• Good soil cover, slow but dense growth.
• Sow in spring or autumn.

🌾 Rye, oats, wheat

• Perfect for winter: they cover the soil and prevent regrowth of unwanted weeds.
• Strong, very structuring roots.

🌼 White mustard

• Very quick to sprout (a few days).
• Occupies the soil between two spring or summer crops.
• Warning: from the Brassicaceae family, avoid just before or after cabbages.

🍀 Alfalfa

• Fixes nitrogen, aerates the soil deeply, long coverage duration.
• Ideal for tired or depleted soils.

3. When to sow green manures?

🗓️ Spring (March to May)

• Phacelia
• Mustard
• Crimson clover

🗓️ Summer (June to August)

• Mustard after harvesting potatoes or garlic.
• Phacelia on soil freed in July-August.

🗓️ Autumn (September to November)

• Rye, oats: to cover the soil during winter.
• Clover to sow before a demanding crop the following spring.

Tip: sow in rows, broadcast, or in strips, according to your preferences and available space. Lightly cover the seeds, water, and let it do its work.

4. When and how to cut them?

• Before flowering to avoid seed setting.
• Mow or cut close to the ground, let dry in place (mulch effect), or lightly incorporate into the soil.
• Allow a resting period of 2 to 4 weeks before the next crop.

5. Where to integrate them in a crop plan?

Green manures are ideal:

• Between two main crops (rotation or fallow).
• At the beginning or end of the season on “empty” plots.
• In garden areas at rest (tired, uncultivated soil).

Conclusion

Sowing green manures means taking care of the soil between two harvests. It is simple, inexpensive, and deeply effective. Whether you are in the city, countryside, on mounds or in containers, they will always find a place. A small gesture… for a big impact.

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