We explore development of elementary preservice teachers' reflective practices as they solved problems encountered while teaching in a reading clinic. Written reflections (N = 175) were collected across 8 weeks from 23 preservice teachers and analyzed to investigate relationships among problem exploration, teaching adaptations, and problem resolution. In this sequential mixed methods design, exploratory qualitative analysis revealed co-occurrence of problem exploration, instructional adaptation, and problem resolution. Confirmatory quantitative analysis found significant relationships: preservice teachers who engaged in more problem exploration or description of instructional adaptations reported more problem resolutions the following week. Results support mixed method, longitudinal analyses to analyze preservice teachers' written reflections, and use of written reflections with responsive feedback to develop preservice teachers' agency for problem solving.