Greetings, For those interested in Michigan sustainable agriculture, an upcoming workshop in Castro Valley, California is well worth considering, both as a profound learning experience and a vacation. It is run by Dr. Elaine Ingham, the world authority on soil biology and the relationship between the myriad of micro life in the soil to the health of plants and trees. In short, healthy soil produces healthy micro life which equates to healthy plants and trees. This is the foundation for true organic agriculture, a critical point often missed in the discussion of the subject. Additional info on the workshop is here: http://www.soilfoodweb.com/04_news/calendar.htm If you just want an introduction to the subject, buy her introductory book, "Soil Biology Primer" and also, her 134 minute lecture cd, "Introduction to the Soil Food Web 2nd ed." available here: http://www.soilfoodweb.com/02_resources/index.html I have many of her works. You will not be disappointed. Also, you will then never refer to soil as dirt. Regards, Lowell Prag