Jack's Nutrients Magnesium Sulfate Epsom Salts vs Supply Solutions Calcium Nitrate 15.5-0-0

These are not substitutes. Jack's is pure magnesium sulfate (Epsom salt), a secondary-nutrient boost for magnesium and sulfur. Supply Solutions is calcium nitrate, a primary nitrogen-plus-calcium fertilizer. Buy Jack's to fix magnesium deficiency or run the Jack's 3-2-1 program. Buy Supply Solutions when you need nitrogen and calcium, especially to prevent blossom end rot in tomatoes and peppers. Both are water-soluble and work in soil or hydroponics; Jack's is the cleaner single-nutrient input, Supply Solutions does more per scoop but is a blunt instrument for magnesium problems.

• Choose the Jack's Magnesium Sulfate if your plants show interveinal yellowing, you run the Jack's 3-2-1 schedule, or you want a pure Mg and S source with no nitrogen.
• Choose the Supply Solutions Calcium Nitrate if you need fast nitrogen for leafy growth or calcium to stop blossom end rot on tomatoes and peppers.