Sustainable Soil Enrichment at Domaine Mirabeau

Domaine Mirabeau holds the AB Bio certification, signifying our dedication to organic farming. For the past three years, we have embraced regenerative agriculture to enhance the quality of our wines and improve soil health. In line with this ethos, Pascal, our Domaine Manager, pioneered the production of compost tea, a natural fertilizer teeming with microorganisms applied to our vineyard soils. This year, our goal is to take it a step further by creating a 100% self-made compost tea using our own vermicompost.

What is a vermicompost?

Vermicompost is a carefully crafted blend of grape marc, vine prunings, and other organic materials collected from our vineyard. Earthworms are introduced to composting beds, breaking down the organic matter into nutrient-rich compost.

How does a vermicompost work?

As the worms digest the organic matter, they produce vermicast—a nutrient-rich cast brimming with beneficial microbes. After a maturation process, resulting in a dark, rich compost with a neutral pH and low carbon-to-nutrient ratio, it is ready for direct application or transformation into compost tea.

Creation of the compost tea

In a brewing container, water and compost are combined in specific ratios within a filter bag. Through aeration facilitated by an aquarium pump, we allow it to brew for 24 to 48 hours, multiplying nutrients and microorganisms, creating a concentrated compost tea.

Application on the vines

Pascal has developed a system for the even distribution of compost tea directly on the soil next to the vines.

What are the benefits for the vines?

The application of the compost tea on the soil of our vineyard has plenty of benefits for the vines and as well the quality of our wines.
 
Enhanced Soil Health: Vermicompost acts as a natural soil conditioner, improving structure and water retention, crucial for optimal root development and nutrient absorption. Addressing a significant challenge in our vineyard, where rainfall is scarce and we refrain from artificial watering, the effective absorption and retention of rainwater by the soil are very important.
 
Nutrient-rich grapes: Nutrients released by vermicast contribute to overall grapevine health, resulting in a more complex flavour profile and a distinct expression of terroir.
 
Reduced Environmental Impact: The vermicomposting technique aligns with Mirabeau’s commitment to sustainable ethos. By recycling organic waste from the vineyard itself, the practice reduces the need for external fertilizers and minimizes the environmental footprint of the winemaking process.
 
Bolstering Biodiversity: Earthworms and improved soil health foster biodiversity, contributing to a balanced and resilient vineyard ecosystem.