The Co-creation workshop is widely used as a qualitative design (research) approach in understandings of service provision, and is here applied to sustainable design, but there is no one-size-fits-all plan for co-creation. Therefore, our research questions are (1) how to apply co-creation workshop methods for grassroots communities on the unfamiliar ‘Net-Zero’ concept, and what are practical challenges to be mitigated and how? We researched this through a case study, and here present three key challenges we experienced when conducting a qualitative study on grassroots community opinions/attitudes towards the UK government’s ‘Net-Zero’ strategy. Firstly, recruiting and engaging with participants are challenging because (A) the ‘Net-Zero’ concept is unfamiliar, and (B) grassroots are in general less well organized and lack clear communication channels. Secondly, finding alternative ways to recruit participants in a short time is challenging, and thirdly, conducting research in the ‘wild’ way is difficult. From our co-creation experience, advisable solutions to the challenges (as our research contributions) include (1) quickly developing or having a well-prepared alternative plan to actively talk to and invite potential participants to the research location, (2) using alternative qualitative research methods such as short semi-structured surveys or interviews to do on-site ‘pop-up’ research in the wild, and (3) to locate a workshop where is easier to find participants in the ‘pop-up’ way and so gather data that can be clearly communicated to the stakeholders able to design and implement future sustainable development for the local community and the future sustainable design of the local environment and energy provision.