A composition and method of protecting plants such as citrus trees, as well as other fruits and vegetable plants from damage due to exposure to frost during periods characterized by a rapid drop in ambient air temperature. The composition is formulated and applied in a manner which facilitates the formation of a coating on the exterior surfaces of the plant, thereby preventing direct contact of the frost with the exterior of the plant and preventing cellular degeneration. The composition is further formulated to have a sufficient viscosity to accomplish adequate coating yet assure easy removal during periods of rainfall or irrigation by sprinkling. The composition comprises a lignin sulfonate, which serves to regulate viscosity and a chloride salt brine solution, such as magnesium chloride, to reduce the freezing temperature. A significant bulk of the composition comprises any one of a plurality of organic by-products having sufficient nitrate content to be of nutritional benefit to the surrounding soil in which the plant is grown, wherein such organic by-products includes steepwater solubles, vintners' condensed solubles, brewers' condensed solubles, distillers' condensed solubles and whey.
