Diverse forms of material expressions can be achieved through practices that cross-fertilize biology and design. Growing Design is one such practice in which designers grow materials from living organisms, such as bacteria, algae or fungi. While this emerging practice may facilitate novel product ideas, the grown materials, to date, are often used in applications as surrogates for conventional materials. A recently introduced method, Material Driven Design (MDD) (Karana, Barati, Rognoli, & Zeeuw van der Laan, 2015), can support designers in finding novel application ideas for a material in development, by providing the ways in which the unique technical and experiential qualities of the material are emphasized and bridged in an appropriate and creative manner. The present paper explores the journey of a product design master’s student, who followed the MDD method through a six-month graduation project, in search of a product application idea for a material that is intentionally grown for design purposes, namely, mycelium-based materials. We provide a practical understanding of how the material-driven design process evolves when the material grows, and elaborate on the product application concept through the lens of materials experience, which is the main motivation for the research and design activities throughout the project. We further speculate on the tools and activities that the student incorporated in the design process to tackle uncertainty as to the micro-organism’s agency, its unique temporality, and the acceptance of the material in society.