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Basalt - Finely Ground Volcanic Rock Dust

Price From €6.49

Soil additive made of basalt rock dust. German origin. Contains a high content of readily metabolisable silica and lime which promote soil fertility and the avoidance of micro-nutrient deficiencies. Approx. 44% silica, 9% CaO, and 11% iron oxide. More details below.

Basalt Rock Dust

This finely ground rock dust will improve heavier soils and the health and taste of the crops grown. It can also be used to enrich compost. Basalt can also mop-up Carbon Dioxide. Please see this article in the Guardian for more info.

Application rate:

  • For soil improvement with regular use about 100-150g/m², or 1,000 kg/ha
  • For soil remediation and in acidified soils up to 500g/m²
  • When composting sprinkle about 20 kg/m³ of compost material

Plants benefit in many ways from adding silica to the soil. These benefits include greater tolerance of environmental stresses, such as heat, cold, drought, salt buildup, mineral toxicity or deficiency. They also, experience accelerated growth rates, and improved resistance to insects and fungal diseases. Silica is an essential building block for the structure of your plants.

Plants incorporate silica into their cell wall, which then acts as a barrier against invading fungi such as powdery mildew and Pythium (root rot), significantly reducing the need to use fungicides. Additional silicon is stored as protection and foundational support between cells, making plants more resistant to insects and other environmental stresses, such as heat or drought.

Thicker cell walls also build bigger stems and branches, which in turn allows more food and water to move through the plant. Leaves are thicker and darker green compared to those grown without soluble silicon. This produces a stronger plant overall, with higher chlorophyll production and greater rates of photosynthesis and growth. As a result plants are able to produce heavier fruits, vegetables, and flowers on branches that support the extra weight. The shelf life of cut flowers and specialty crops is also extended.

The benefits of silica are particularly evident in stressful situations. Following a fungal infection, greater deposits of silicon are found around the affected plant tissue showing that silicon is selectively accumulated at the site. The silicon deposited at the sites of infection form stronger, harder cell walls in order to deter the fungus.

The analysis average is:
SiO2 — 49.97
TiO2 — 1.87
Al2O3 — 15.99
Fe2O3 — 3.85
FeO — 7.24
MnO — 0.20
MgO — 6.84
CaO — 9.62
Na2O — 2.96
K2O — 1.12
P2O5 — 0.35

Approved for use on organic holdings subject to approval from your certification body.

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