Home gardens are one of the most adaptable agricultural systems in time, because they have the capability to convert their production from external to internal necessities through changing the type of plants in the plot. For example, home garden structure and function varies in response to the modernization process. Home gardens in villages in the outskirts of cities tend to have more ornamental species and commercial fruit plants than home gardens in isolated villages.
The term "home garden" has been used rather loosely to describe diverse practices, from growing vegetables behind houses to complex multi-storied systems. Home gardens involve the intimate association of multipurpose trees and shrubs with annual and perennial crops and, invariably livestock within the compounds of individual houses, with the whole crop-tree-animal unit being managed by family labor.
In spite of the very small average size of the management units, home gardens are characterized by a high species diversity and usually 3-4 vertical canopy strata, which results in intimate plant associations. The layered canopy configurations and combination of compatible species are the most conspicuous characteristics of all home gardens. Contrary to the appearance of random arrangement, the gardens are usually carefully structured systems with every component having a specific place and function.
In general terms home gardens consist of a herbaceous layer near the ground, a tree layer at upper levels, and intermediate layers in between. The lower layer can usually be partitioned into two, with the lowermost (less than 1 m height) dominated by different vegetable and medicinal plants, and the second layer (1-3 m height) being composed of food plants such as cassava, banana, papaya, yam, and so on. The upper tree layer can also be divided in two, consisting of emergent, fully grown timber and fruit trees occupying the uppermost layer of over 25 m height, and medium-sized trees of 10-20 m occupying the next lower layer. The intermediate layer of 3-10 m height is dominated by various fruit trees, some of which would continue to grow taller. This layered structure is never static; the pool of replacement species results in a productive structure which is always dynamic while the overall structure and function of the system are maintained.
The multilayered Chagga home gardens (Mt. Kilimanjaro, Northern Tanzania) are characterised by an intensive integration of numerous multipurpose trees and shrubs with food crops and animals, simultaneously on the same unit of land. The Chagga are skilled farmers with an intimate knowledge of the crops and their ecological requirements. They have a good idea of functions/uses of the plant species on their farms. The large species diversity provides both subsistence and cash crops. It enables the farmer to keep his management options open and provides insurance against drought, pest and economic risks.
The Javanese pekarangan home garden system is a clean and carefully tended system surrounding the house, with plants of different heights and architectural types, though not planted in an orderly manner, optimally occupy the available space both horizontally and vertically. The home gardens in the Pacific Islands present a more clearly defined arrangement of species following the orientation and relief characteristics of the watershed. The West African compound farms are characterized by a four-layer canopy dominated by a large number of tall indigenous fruit trees.
One of the ways we can begin solving our global environmental problems is by growing our own food. This puts us back in touch with the cycles of life and death -- from plant to food to offal to decay to soil to plant again. Might this be the underlying mission of sustainable agriculture?