Calcium nitrate fertilizer is a highly water-soluble compound used in agriculture and gardening. This inorganic salt delivers two distinct nutrients readily available for immediate plant uptake. Its effectiveness in resolving common crop disorders makes it valuable for commercial farmers and home growers aiming for high-quality produce. This guide explores the fertilizer’s composition, identifies the deficiency symptoms it corrects, details where it can be purchased, and outlines proper application methods.
Understanding Calcium Nitrate
Calcium nitrate (Ca(NO3)2) provides two separate, fast-acting components. It typically contains about 15.5% nitrogen and 19% calcium. It contains nitrogen almost entirely as nitrate, the preferred and most easily absorbed form of nitrogen for most plants.
Calcium is a secondary macronutrient that serves a major structural role. Calcium ions are incorporated into plant cell walls, forming calcium pectate that acts like a cellular cement. This structural reinforcement leads to sturdier plant tissues, stronger root systems, and better overall resistance to stress and disease. The nitrate form of nitrogen simultaneously fuels rapid, leafy vegetative growth and promotes the uptake of the calcium ion by the plant roots.
Identifying the Need for Calcium Nitrate
Specific disorders in susceptible crops signal the need for a soluble calcium boost. These symptoms are linked to localized calcium deficiency in new growth or developing fruit, often due to poor transport rather than a lack of soil calcium. Calcium is immobile within the plant, meaning it cannot be relocated from older leaves to newer growing points.
One common sign is Blossom End Rot (BER), affecting fruiting crops like tomatoes, peppers, and watermelons. BER manifests as a dark, sunken, leathery spot on the bottom end of the fruit farthest from the stem. In leafy greens such as lettuce and cabbage, calcium deficiency causes Tip Burn, characterized by browning and necrosis of the margins on the youngest, inner leaves. Apple growers look for Bitter Pit, a disorder presenting as circular, slightly depressed spots on the fruit skin, with brown, spongy tissue developing beneath the surface.
Purchase Points and Formulations
Finding the right product is essential, and the purchase avenue depends on the quantity needed. For home gardeners, local retail options like garden centers and farm supply stores are the most convenient sources for smaller bags. These stores often stock brand formulations marketed for use on tomatoes and other vegetables.
Online purchasing provides access to a wider variety of specialized products and is the best option for bulk quantities. Major e-commerce platforms carry smaller packages, while specialized agricultural and hydroponic supply websites offer large bags at a lower cost per pound. Buyers should compare prices on these specialized sites, as the fertilizer grade and total nitrogen-to-calcium ratio can vary between manufacturers.
Calcium nitrate is sold in three commercial forms, each suited for a different application method. Water-soluble powders or fine prills are the most common, preferred for mixing into liquid solutions for foliar sprays or fertigation systems. Granular forms, sometimes coated, are intended for dry application as a soil amendment or side dressing. Liquid concentrates offer convenience for small-scale use or immediate incorporation into drip systems.
Proper Application Techniques
Correct application of calcium nitrate is important for safety and effective nutrient absorption. Personal protective equipment (gloves and eye protection) should be worn during handling, and the product stored in a cool, dry place away from combustible materials. The application method chosen often depends on the severity of the deficiency and the size of the crop.
For soil drench or side dressing, the granular form is placed around the base of the plant, several inches from the main stem, at a rate of one to two tablespoons per plant. This application must be followed by thorough watering to dissolve the product and move the nutrients into the root zone for absorption. Foliar spraying is the fastest way to correct an acute calcium deficiency in fruit or leaves, but it requires careful dilution, typically mixing one to two tablespoons per gallon of water.
Foliar sprays should be applied during the cooler parts of the day, such as early morning or late evening, to prevent the moisture from magnifying sunlight and causing leaf burn. For advanced growing methods, calcium nitrate is valued for use in fertigation and hydroponic systems due to its high solubility. Never mix concentrated calcium nitrate solutions with fertilizers containing sulfates or phosphates. The calcium will immediately react with these compounds to form insoluble precipitates like gypsum or calcium phosphate, which will clog irrigation equipment and prevent the nutrients from ever reaching the plant roots.