Volcanic Rock Dust (Basalt) 5KG

The reason we use Volcanic Rock Dust in potting soils and living soil blends is for the for mineral content, mainly Silica. Silica is essential for optimal plant health and vigour, but is lacking from commercial soil mixes. It isn’t tested for on most soil tests and is often overlooked but having a good Silica content in your soil will amaze you with the results.

It is formed when volcanic eruptions deposit molten rock full of minerals to the earths surface, it gets moved around by glacial action and pushed to places where we can access it by excavating and breaking into small chunks and dust. In soils with good sand content, silica is present but in soil less mediums like organic potting soils, unless sand is added, silica may be missing. Basalt is a great way to bring silica in, but with extra minerals that sand does not.

Volcanic basalt contains concentrated amounts of trace elements and minerals that are long lasting, it does take a long time to break down so we tend to use plenty of it – the finer particles get mineralised first and as the microbial population develops they go to work on the larger pieces.

When making soil mixes we usually use 4 cups per 50L to ensure there is plenty for microbes to get working on, there is no danger of using too much and releasing too much too soon so it’s one amendment where plenty is better.

Our latest batch comes from Scotland, analysis below: