The purpose of this action research study was to develop a rubric that identified levels of integrated science, technology, engineering, and mathematics (STEM) lessons through agriculture, food, and natural resources (AFNR) lessons that were developed and implemented in afterschool programs by preservice informal educators. The research study expanded on the knowledge base by identifying three levels and six features of integrated STEM through the context of AFNR. Using the rubric, we analyzed 10 mini-units, consisting of 27 lesson plans, of STEM integrated AFNR lesson plans that were developed by preservice informal educators. There were three major findings. First, teaching AFNR content and skills was the main focus of integrated STEM lesson plans. Second, the lesson plans attempted to use real-world problems to connect students' learning to use content knowledge and skills to solve the problem, yet failed to connect other disciplines. Finally, students who had previous teaching experiences in non-formal and informal settings achieved the highest scores, but students who were in formal teacher preparation programs had the lowest scores in terms of developing integrated STEM through AFNR lesson plans.