Calcium Nitrate Fertilizer 15.5-0-0 (Ammonia Calcium Nitrate 15.5-0-0)

Calcium Nitrate Fertilizer 15.5-0-0 is a 100% water-soluble source of 15.5% nitrogen and 19% calcium — two of the most in-demand plant nutrients delivered in a single dissolving step. The nitrogen is almost entirely fast-acting nitrate, plant-available the moment it dissolves, and the formula contains no phosphate or potash.

Nitrogen drives chlorophyll production, protein synthesis, and vegetative growth, while calcium supports cell-wall structure in fruit and leaf tissue that expands fastest. Nitrate is also the preferred nitrogen form for calcium-sensitive crops, since ammonium competes with calcium for uptake at the root. Calcium nitrate is widely used as a sidedress for tomatoes, peppers, and cucurbits, as a clean phosphate-free calcium and nitrate source for hydroponic and fertigation systems, and as a low-rate foliar supplement during rapid growth. It dissolves completely with no residue and has a near-neutral effect on soil pH.

One essential handling rule: calcium and concentrated phosphate or sulfate fertilizers should never be combined in the same stock tank, as they form an insoluble precipitate — keep calcium nitrate in a separate stock tank and combine only in the dilute solution. Water in dry applications, apply foliar sprays in cool conditions, and store sealed and dry, as the product is hygroscopic.

CDFA registered and third-party lab tested for heavy metals, with results consistently well below required limits.