The Brief Students at Barack Obama School of Leadership and STEM in Chicago Heights grow watermelon, peppers, tomatoes, and zucchini in their school garden. They sell the produce at a weekly farmer’s market while applying STEM lessons — using fractions and percentages to set prices below grocery store costs. The Barack Obama School of Leadership and STEM in Chicago Heights is turning the soil into a syllabus. We have really big banana peppers," Logan said. What's next:The farmer's market runs every Wednesday morning through Oct. 1 at Barack Obama School of Leadership and STEM in Chicago Heights.