Dewitt 3-Foot by 250-Foot Thermal Blanket DTB3 Dewitt thermal blanket is designed to let rain and irrigation through to your nursery stock, while holding in precious heat DeWitt thermal blanket is a 3-ounce white, non-woven, needle-punched polypropylene material No need to worry about foliage burn due to the fabrics permeability, can remain in use even on sunny days Great for late fall and early spring applications to extend your selling seasons Dewitt thermal blanket also makes an effective alternative for over-wintering perennials and other ornamentals