Permaculture Principles are based on close observation of nature, traditional sustainable agriculture systems earth sciences and common sense. It has been noticed that there is more life on the edge where two systems overlap. Systems can then access the resources of both. Use the edge effect and other natural patterns observed to create the best effect. (There are no straight lines in nature.)
If a pond or dam has a shallow ledge it provides places for fish to breed, for plants to grow which can feed the fish. Also, with a wavy edge it can provide more edge for this habitat.
Plants at the edge of beds often yield more than the ones in the center, so patterns that increase edge in beds will boost production. Rows of tall plants can be alternated with short ones to achieve the same effect. To increase the number of plants that can fit into a given space, place them in a wavy pattern rather than a straight line.
In general, straight lines and smooth shapes reduce the amount of edge, while shapes with lobes, notches, mounds, pits, crinkles, and crenellations will increase edge. Don’t forget about extending the edge effect into the third dimension by varying the height and depth of plantings, soil, structures, and ponds. The importance of edges is simply one more manifestation of the role of connections in the ecological garden. Edges are not a static place; they are the result of a relationship between two or more dynamic pieces of the living landscape.
In the garden, we’re working with live beings, not just shapes and colors. These creatures grow, set seed and multiply, and in time they die. Plants, insects, birds, and all the rest connect in a tight weave and enter each others’ lives, creating and sharing among them food, shade, pollen, seeds, humus, perches, burrows, nests a host of varied and valuable gifts. With a gentle, careful gaze we can peer into this wonderfully interlaced world and tease out some of the connections, transferring them to our own landscapes. Nature carries the instruction book for a sustainable world—it is up to us to read it and to preserve it.