Potassium Nitrate NPK 13 0 45 Water Soluble Fertilizer is 100% Water Soluble White Crystalline Free Flow Powder. Potassium nitrate is a source of potassium and nitrogen, two macronutrients (primary nutrients) essential for plant nutrition and growth. Since healthy growth requires large amounts of nitrogen and potassium, those elements have to be applied to the soil in order to achieve healthy growth. (For Further query related product- please ask question below)