Walnut Hulls

Description

Walnut hulls are the outer green shells of walnuts. In addition to the plant’s young green leaves, its bork and roots, especially the outer walnut hulls have been used as dye for coloring textiles and skin for a long time. Two species of walnut in particular are noted as historical sources of dyestuffs: The common walnut (also English walnut), Juglans regia L., and the Eastern black walnut, Juglans nigra L. Both belong to the family of the Juglandaceae. The principal coloring matters pyrogallol and hydro juglone are found in the outer green walnut shells. In an alkaline solution, pyrogallol oxidizes to a brown dye. Hydro juglone, which is mostly found in the dry shells, oxidizes to the generic compound juglone after contact with air. In addition to these naphthochinone dyes, walnut shells also contain tannins. Since ancient times, walnut hulls have been used to dye wool and other fabric. Dried darkbrown hulls make beautiful deep brown hues, while fresh hulls should be soaked in water for 24 hours to increase the amount of the coloring agent juglone.