¶ Starch
Starch serves only as a crafting material for certain Holoitems and has no other practical use.
¶ Crafting
Starch belongs to Lamy's collection and does not have a prerequisite to unlock it's crafting recipe. It is also used in other items belonging to Lamy's collection, that being Sake.
To get Starch, two Azure Bluets, a flower specific to the plains biome, must be placed in the crafting menu to craft starch. Before Starch had the same recipe as light gray dye and overwritten said recipe. This was changed to allow Azure Bluets to be crafted into gray dye.