Dewitt's Thermal Blanket is 2.5 oz. white, non-woven, needle-punched polypropylene material. The Thermal Blanket is made to trap heat while still allowing rain and irrigation to reach your nursery stock. The frost cover can be used even on sunny days because of the permeability of the frost cloth, which means there is no need to worry about foliage burn. To lengthen your selling seasons, this product is fantastic for late fall and early spring applications. It works well as a row cover or substitute for perennials and other ornamentals that overwinter.