K-Mag Fertilizer 0-0-22 (sulfate of potash magnesia, also called langbeinite) is a naturally mined mineral fertilizer that delivers three nutrients in a single soil-applied product: 22% soluble potash (K₂O), 11% magnesium, and 22% sulfur, with less than 2.5% chloride and no nitrogen.
Potassium supports fruit size, sugar movement, and stress tolerance; magnesium is the central atom of every chlorophyll molecule; and sulfur is required for protein synthesis and enzyme function. The low chloride content makes K-Mag well suited to chloride-sensitive crops such as potatoes, tomatoes, peppers, berries, and tobacco, and the absence of nitrogen makes it useful for late-season feeding during fruit development. Because langbeinite is less soluble than refined potassium salts, it dissolves gradually as soil moisture moves through the root zone, providing nutrient availability over weeks.
K-Mag is a soil-applied fertilizer for vegetables, fruit trees, berries, field crops, and pastures — broadcast, top-dress, or side-dress, then water in. It is not fully water-soluble and is not intended for foliar spraying or recirculating hydroponic systems. Keep the product away from direct stem and trunk contact, and store sealed and dry.
CDFA registered and third-party lab tested for heavy metals, with results consistently well below required limits.