Weather balloon flights provide affordable access to a space-like environment for student research. Typical flights last for 2.0-2.5 hours and reach altitudes of approximately 30 km. Payloads are exposed to intense cosmic and ultraviolet radiation, temperatures below -60° C, and atmospheric pressures of approximately 0.01 atmospheres. We report on simple laboratory procedures intended primarily for high school and middle school students in studying the effects of high-altitude balloon flights on yeast and plant seeds.