Powdered fertilizers must be dissolved with water before use. Dissolve powders thoroughly in a small volume of water, then pour the resulting solution into a larger volume of water. Heating water helps powders dissolve better. Calcium and magnesium powdered fertilizer needs to dissolved with water independently of other fertilizers because it can cause clumping when mixed at same time with phosphorus and sulphur. Always use a mask when working with fertilizers to avoid inhalation.