What is Permaculture?
Permaculture is eco agricultural approach that encourages you to design with natural systems and sees strength in diversity.
It teaches you to utilize all your land in the best way possible to fill your belly - like creating a food forest! Perennial plants are key, managing water usage and storage plus utilizing everything to eliminate waste are 3 core aspects of Permaculture. With these principles in place, this system can be scaled both to small and large spaces.
We have been practicing this on our organic farm for 15 years. Bill Mollison and David Holmgren coined the term and wrote the book Permaculture : A Designer's Manual back in 1978. This book offers a ton of information and on the web there are wonderful online communities available to become a part of like Permies. Here is a comprehensive list of great books worth investing in. Also, here are Permaculture Design Principles for a better understanding.