Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel, mineral wool, or coconut husk. Aquaponics is a sustainable food production system that combines a traditional aquaculture (raising aquatic animals such as fish, crayfish or prawns in tanks) with hydroponics (cultivating plants in water) in a symbiotic environment.
Permaculture is an approach to designing human settlements and agricultural systems that are modeled on the relationships found in natural ecologies. Permaculture is sustainable land use design. This is based on ecological and biological principles, often using patterns that occur in nature to maximise effect and minimise work. Permaculture aims to create stable, productive systems that provide for human needs, harmoniously integrating the land with its inhabitants. The ecological processes of plants, animals, their nutrient cycles, climatic factors and weather cycles are all part of the picture. Inhabitants’ needs are provided for using proven technologies for food, energy, shelter and infrastructure. Elements in a system are viewed in relationship to other elements, where the outputs of one element become the inputs of another. Within a Permaculture system, work is minimised, "wastes" become resources, productivity and yields increase, and environments are restored. Permaculture principles can be applied to any environment, at any scale from dense urban settlements to individual homes, from farms to entire regions.
