The study of plant biology in environments beyond Earth’s gravity emerges as a crucial scientific pursuit as humankind prepares for establishing a permanent presence on the Moon and Mars. Migrating from short durations in space to creating permanent habitats to facilitate life around celestial bodies elicits strong research focus on space food security. Space agriculture has extended beyond survival to include mental health, cultural identity, and the shaping of habitation in the future. Plants not only are vital for sustenance but also play a key role in oxygen production, water recycling, and psychological well-being, which are essential for prolonged human space missions. Transitioning from the gravitational conditions of Earth (1 g) to the altered gravity environments of space travel poses fundamental challenges for plant growth, morphology, cellular orientation, and biochemical processes. Space plant biology, thus, is not only about growing crops on planets but also about nurturing life systems while navigating the cosmos. This chapter explores a spectrum of phenomena, from the influence of gravity in evolutionary processes on Earth to plant adaptations under conditions of microgravity and hypergravity. We assemble information from space experiments conducted on the International Space Station (ISS), BIOS-3, Veggie, and China’s Tiangong and augment it with ground-based studies using clinostats, RPMs, and centrifuges. This chapter also summarizes the evolution of human food systems in space, from simple, packaged foods to complex, self-sustaining, culturally integrating bioregenerative systems. Combined with knowledge gained from experiments on board the ISS and Tiangong, and in the EDEN International Space Station (EDEN-ISS) – and Mars Desert Research Station (MDRS) – simulated environments, crops grown in environmentally challenging habitats are more desirable for space food security. In addition, this chapter addresses the broader relevance of agricultural technology for space applications.