Hi-Yield Calcium Nitrate is a fertilizer containing 2 important nutrients that plants need: Calcium (Ca) and Nitrogen (N). Used primarily in vegetable gardens, particularly for Tomatoes and Peppers, in the prevention of Blossom End Rot. Blossom End Rot is a common problem with Tomatoes. It is a physiological disorder (not a disease) caused by a lack of Calcium. Apply at a rate of 1 cup per 50 feet of row or 1 level teaspoon per each plant. 15.5-0-0