Organizational routines have been a useful concept to understand how organizations work. In interorganizational settings, routines can largely influence the effectiveness of interfirm coordination and cooperation. New routines are often required to set up to facilitate the workflow between organizations and to balance competition and cooperation dynamics. Although we have a much better understanding of how routines are both for stability and change, we do not yet have a clear idea of how routines are born and established. In this paper, we chose to study the routine formation process and dynamics in a temporary interorganizational project, as establishing routine swiftly is vital for the survival and success of temporary organizations in an increasingly projectified society. Using an ethnographic approach, we investigated a Horizon 2020 innovation project and how its actors managed to establish the chicken sampling routine at the beginning of the project as fast as possible. In addition to the ostensive and performative aspect of routines, we identify a projective perspective that actors reflectively project and establish new routines in a layered process. We highlight the need to further explore when routines are born to better understand the lifecycle of organizational routines. In the end, we give practical suggestions to managers how the projective aspect of routines can be helpful in their day-to-day organizational life.