The goal of space farming is to sustain humans in lunar and martian colonies, which provide shelter and life support in hostile environments. Space imposes new requirements on production agriculture that are not typically encountered on Earth: low gravity, low pressure, elevated CO₂ concentrations, as well as mass and energy constraints. The design of space farms has benefited from developments in ecophysiology and biological engineering, resulting in new lighting, sensor and cultural technologies. An initial concept for a space farm is a salad machine, a small controlled environment (CE) for supplementing crew diets with fresh vegetables on a continuous basis. The productivity of the salad machine will be optimized using CE research combined with proven farming methods, so lessons learned in its design have terrestrial applications. Currently, agriculture faces new challenges from environmental change caused by anthropogenic activities during the last 200 years that have altered the global climate. The impacts of these climatic changes on the Earth and its ecosystems can be minimized with solutions that reduce carbon emissions, improve water use efficiency, maintain air quality, and lead to sustainable agriculture. The salad machine concept is a possible CE solution to bolster urban agriculture because local food production reduces transportation time and carbon costs for delivering fresh produce to cities. Integrating such salad machines with rain-fed and reclaimed grey water or with recycled organic wastes via composting could further improve the sustainability of modern cities. More intensive CE solutions, like the development of large plant factories for growing food and energy crops using new LED lighting could also improve agricultural production in a world experiencing shortages in arable land and increasing population.