This study explores how children's agency can be supported in spontaneous, multiparty conversations on emergent science topics in outdoor kindergarten settings. We analyse a student teacher’s practice through a critical case study, focusing on how specific interactional moves, especially contextualised, unaddressed invitations, create space for children to participate and inquire. Using dialogic and interactional theory, the analysis highlights how pauses, embodied orientation, and minimal responses invite children to self-select into conversations without explicit turn allocation. The findings show that while these flexible strategies foster child-led exploration and relational engagement with nature, they also pose challenges for sustaining deeper scientific inquiry. The study contributes to research on early science education by offering new insight into how agency unfolds in polyphonic and dynamic ways during multiparty interactions. From a sustainability perspective, such conversations can nurture early ecological awareness through shared, inquiry-driven experience in natural environments. This suggests that teacher education should focus on developing professional sensitivity to spontaneous moments of inquiry. Student teachers and teachers must balance openness with the ability to recognise and scaffold conceptual learning in unpredictable, group settings.