When we talk about successfully creating a garden, we often think of plants, exposure, or watering. But there are discreet and essential players that we too often forget: earthworms and the soil microfauna. These small organisms work in the shadows, but without them, the fertility of the soil and the health of the plants would be compromised.
Why are earthworms essential?
Earthworms are true soil engineers. Their role is multifaceted:
- Aeration: by digging galleries, they allow the roots to breathe better.
- Drainage: their tunnels facilitate the infiltration of water, limiting flooding.
- Fertilisation: their excretions, called turricules, are rich in nutrients that are directly assimilable by plants.
- Decomposition: they recycle organic matter (dead leaves, roots) into fertile humus.
For example, one hectare of fertile soil can contain up to 2 tonnes of earthworms and produce more than 25 tonnes of manure per year.
The microfauna: a hidden biodiversity
Beyond the worms, the soil harbours a multitude of microscopic organisms:
- Bacteria and fungi that decompose organic matter.
- Springtails and mites that regulate organic waste.
- Mycorrhizae that form an alliance with roots and improve the absorption of water and nutrients.
This underground biodiversity creates a natural balance and contributes to the garden's resilience against diseases or climate stress.
How can we promote this underground life?
A living soil is cultivated and maintained:
- Limit soil cultivation: avoid turning the soil deeply, as this destroys the galleries.
- Bring organic matter: compost, mulch, manure… to nourish the microfauna.
- Avoid aggressive chemicals: pesticides and herbicides are highly detrimental to soil life.
- Maintain a plant cover: lawns, mulch, ground cover plants protect and stimulate biodiversity.
In summary
The earthworms and microfauna are the true invisible allies of the gardener. By respecting them and nourishing their habitat, one achieves fertile soil, more vigorous plants, and a sustainably balanced garden.