Controlled-environment growing
Controlled-environment growing is the successful marriage of technology with plant biology. By using greenhouses to control heat and air conditions, using artificial lighting to control light levels, using nutrient solutions to control the nutrition plants receive through their roots, and otherwise tweaking the environment that we grow plants in, it is possible to grow more plants in less space than would otherwise be possible. For example, The Institute of Simplified Hydroponics report that in just 20m2 (215 square feet) of space, they regularly grow 2kg (4.4lb) of vegetables per day.
Controlled-environment growing covers the three "ponics": hydroponics, aquaponics and aeroponics.
Open Source Ecology promotes agricultural practices that meet the OSE Specifications i.e. food systems that are open-source, replicable, cheap, scalable, simple to build and maintain, allow automation, promote decentralization, are environmentally-friendly and lead to abundance. Industrial monoculture using petrochemicals and heavy machinery do not meet these criteria, but two methods of agriculture do: permaculture and controlled-environment growing. These two have different strengths and weaknesses; although controlled-environment growing allows city-dwellers with limited space to be self-sufficient for food, it cannot heal bad soils the way permaculture can. And although permaculture can turn wastelands into beautiful forests, it cannot grow beneficial herbs that are not adapted to the local climate the way controlled-environment growing can.