The expansion of human activities beyond low Earth orbit will require sustainable approaches to food production and life-support, particularly for long-duration missions to the Moon and Mars. Astrobotany and space agriculture provide a foundation for developing plant-based systems capable of producing fresh food while contributing to atmospheric regeneration, water recycling, and crew well-being. This article reviews the biological and technological challenges associated with cultivating plants beyond Earth, with particular emphasis on microgravity, partial gravity, ionising radiation, altered atmospheric conditions, restricted root-zone environments, and plant?microbe interactions. It further examines the progression of plant research from early orbital experiments to advanced cultivation platforms such as NASA?s Veggie system and Advanced Plant Habitat aboard the International Space Station. Key approaches for extraterrestrial crop production, including hydroponics, aeroponics, substrate-based cultivation, precision LED lighting, and closed-loop resource recycling, are discussed. The selection of suitable crops is also considered in relation to growth duration, nutritional value, biomass productivity, resource-use efficiency, and space constraints. Beyond food production, plants have potential roles within bioregenerative life-support systems through carbon dioxide fixation, oxygen generation, and water recycling, although current systems remain insufficient to replace conventional life-support technologies completely. The article also highlights how technologies developed for space cultivation, including controlled-environment agriculture, sensor-based monitoring, resource-efficient hydroponics, and precision lighting, can contribute to sustainable agriculture on Earth. Future lunar and Martian cultivation will depend on advances in automation, radiation protection, microbial management, resource recycling, and reliable multi-crop production. Thus, space agriculture represents not only a pathway toward sustainable human exploration beyond Earth but also an important research frontier for developing resilient, resource-efficient agricultural systems on our home planet.