Gaia Greensand 0-0-3 Soil Amendment is an iron potassium silicate containing 7% potassium, 20% iron oxide, and as many as thirty other elements. Greensand loosens hard soils, binds sandy soils, regulates moisture, and assists in the release of other nutrients. This ancient seashore deposit is valued as a slow release source of potash and other essential minerals. Greensand is excellent for loosening clay soils. 1.5kg.