While tea is a central substrate in SCOBY cultivation, its status as an imported plant material in Europe raises ecological and procedural implications that may conflict with Biodesign’s aims of fostering regeneration and biodiversity. This paper frames medium design as a foundational yet underexplored site for integrating alternative substrates into growing design practices. Building on systematic laboratory experimentation, this contribution presents two open-source protocols that support parallel testing of alternative plants into SCOBY nourishing media, enabling both quantitative assessment of biomass production and qualitative evaluation of material expressions. One protocol is grounded in controlled laboratory procedures, while the second is adapted for non-sterile, resource-diverse environments, increasing accessibility across practitioners with varying expertise and infrastructure. The present exploratory research demonstrates how this methodology integrates quantitative and qualitative insights, enabling the evaluation of customised medium protocols and the emergence of novel SCOBY material expressions. In doing so, it supports the integration of biological and epistemological diversity into growing design practices and opens up new research trajectories in plant-based Biodesign and regenerative material cultivation.