Chemboys - XL Cal-Mag 5 GallonChemboys Cal Mag 2 0 0 is a highly fortified calcium and magnesium plant supplement formulated to correct common deficiencies in your plants ecosystem and is critical throughout all stages of growth, especially in heavily fruiting plants and fast blooming annuals. We use a proprietary blend of minerals in our Cal Mag formula to help boost plant yields in fruiting and flowering plant varieties, prevent blossom end rot in tomatoes and peppers, and