A mycelium sheet or panel material which has had an upper portion of its growing surface removed prior to or concurrently with harvest, provides a more homogeneous surface for later processing of the mycelium sheet or panel material into a mycelium-based textile. An additional rinsing step of a mycelium sheet or panel material which has had an upper portion removed provides a surface which is even more amenable to textile processing into a mycelium-based textile. Such removal and rinsing steps produce a mycelium-based sheet or panel material which provide more homogeneity, such as in color appearance or texture, thereby leading to a more homogeneous mycelium-based textile end product. By addressing and eventually removing fungal growth metabolites during the mycelial growth and harvest processes, later textile processing challenges with the mycelium-based material may be eliminated. Undesirable surface irregularities in the mycelium-based material of final textile products may also be eliminated.