DTE Solution Grade Langbeinite is an organic water-soluble powdered mineral derived from Sulfate of Potash Magnesia. This solution grade product provides a balance ratio of potassium (K), magnesium (Mg) and sulfur (S) in a highly available sulfate form. Designed for efficient delivery and quick uptake, this high performance langbeinite will provide your plants with the tools for optimal growth and maximum performance. A soil or plant tissue analysis or a home soil test is recommended before use, but application can be made without one (see instructions for details).