How Does Nitrate Affect Plant Growth?

Nitrates are a source of inorganic nitrogen, the most essential element and nutrient for strong plant growth. In the form of nitrates, nitrogen is quickly released from a fertilizer and taken up by plants in a form they can directly use. However, plants receive most of their nitrogen in an organic form from the soil. Whatever the source, nitrogen affects the growth and strength of plants throughout their life cycle.

Use both nitrates and organic nitrogen for healthy plant growth.


Nitrates are inorganic, quick-release sources of nitrogen. The two most common nitrate fertilizer components are sodium nitrate and calcium nitrate. Inorganic fertilizers are available in either granular or liquid form and have three numbers associated with them. These represent the percentages of nitrogen, phosphorous and potassium, respectively, in the active ingredients of the fertilizer. For example, 30-10-10 fertilizer contains 30 percent nitrates.

Effects of Nitrogen

Nitrogen is responsible for strong vegetative growth of stems, leaves and shoots. As the main constituent of chlorophyll, which is directly responsible for photosynthesis, nitrogen promotes the production of food used by the plant. Sufficient nitrogen levels in the plant result in lush, dark green foliage. A lack of nitrogen shows in stunted plant growth and the plant's leaves turning pale green or yellow.

Natural Nitrogen Cycle

Nitrate fertilizers can supplement the supply of organic nitrogen. Plants mainly receive nitrogen from the atmosphere and from organic matter. The breakdown of organic matter, such as compost or decaying plants, produces the most nitrogen, but it is in a form that plants cannot use. Bacteria in the soil convert this organic nitrogen to inorganic forms for the plant. The plant roots take up the nitrogen and combine it with other organic substances, such as proteins and enzymes, to produce food for growth. People and animals eat the plants, and the animal and plant residues return to the soil to start the cycle over again.

Adding Nitrogen

Except for nitrogen, phosphorus and potassium, most soils already contain adequate amounts of the nutrients necessary for successful plant growth. Gardeners add nitrogen to the soil through an application of fertilizer, either organic compost or inorganic nitrate fertilizer. Annually, dig organic compost into your soil to establish a base level of nitrogen. At the start of the growing season, apply a light application of a nitrogen-heavy fertilizer to prepare the plants for their growth stage. Throughout the growing season, use a nitrate fertilizer as side-dressing for those plants that require an extra boost of nitrogen.