“Effective Microorganisms” or EM is a formula of specially selected microbes which can be used for many applications. For example, they are a metaefficient compost additive. If you add a mixture of them to your kitchen compost and it will decompose more quickly and with less odor.
EM is a microbial consortium (aggregate of more than one type of microbe) that was developed by Dr. Teruo Higa, a Japanese horticulture professor.
Similar to the wine-making process, this system relies on fermentation rather than putrefaction. The ME mixture, called “Bokashi”, is made by mixing sawdust and bran that has been inoculated with the microorganisms. It takes about ten days to do its work, and in the end you are left with nutrient-rich liquid compost. The system will also allow you to compost meat and diary products. A step-by-step guide can be seen here and here. The EM system is very popular with apartment dwellers in Japan and Korea. Real Goods sells a bokashi system. EMTrading has a lot of Effective Microorganism information. Whole Foods will soon be selling EM too.
There are many other uses for EM. The exact microbes in the microbial consortium may vary somewhat over time, but there are certain principles which guide which beneficial microorganisms are included and how they are combined with the other microbes in the formula. It is likely safe to say that the single largest area of EM utility is in farming (agriculture), and even moreso within the realms of organic farming, sustainable farming, or “super-organic” farming. However, EM has also found applications in waste treatment, waste water treatment, toxic waste remediation, remediation of polluted waterways, human and animal health, protecting building materials (architects call EM “building friendly”), and in many other diverse areas as well. See more information here.