Urban green spaces (UGS) are vital for providing cultural ecosystem services (CES) that enhance well-being in cities. CES are co-produced through human interactions with the environment and involve natural, built, human, and social capital. Assessing CES through textual social media reviews on platforms such as Google Maps, offers insights into the intricate relationships between UGS characteristics, human activities, and well-being. However, research gaps regarding the role of co-production factors in the final delivery of CES persist, necessitating an improved conceptualization of CES co-production. This study provides a comprehensive exploration of the co-production of CES in UGS by analyzing 15,450 Google Maps reviews in the German cities of Bochum and Gelsenkirchen. The research assesses both the “use clause” and “ecological clause” of CES, offering a nuanced understanding of user perceptions and the contributions of UGS characteristics. Key findings highlight the entangled significance of CES categories, such as “aesthetic experiences,” “active or immersive interactions,” and “passive or observational interactions,” revealing that aesthetic value acts as a catalyst for both active and passive interactions within UGS. The study also demonstrates the intricate relationship between CES and the (perceived) biophysical environment, suggesting tangible and material connections to the natural and built environment, contrary to existing intangibility claims. The analysis of low-intensity and experience-oriented recreational activities highlights the reliance on specific UGS characteristics. The study concludes by acknowledging the strengths of utilizing textual social media reviews for CES assessment, particularly in their ability to cover a broad range of UGS classes in urban contexts. Our research enhances understanding of CES co-production in UGS, emphasizing the interplay between UGS characteristics, user experiences, and CES co-production. This provides insights for UGS planning and guides research on material aspects of CES co-production and capital interactions.