What is grass mud horse made of?

From your description, the water grass mud is sintered from natural soil, so it is named water grass mud. Water grass mud is a kind of sintering method, which uses instantaneous high temperature to burn the soil into solid particles, which not only retains the nutrients in the soil, but also keeps its shape underwater for a long time. This is grass mud.

Water grass mud is one of the important raw materials for water grass cultivation and landscaping.