Compost induces resistance to a wide array of bacterial and fungal diseases.1 Induced resistance (as opposed to acquired immunity) is a form of epigenetics. That is, how a plant or animal expresses its genes is not controlled simply by the genes themselves, but also how various environmental factors affect that expression. Plants were not intended to be grown in sterile soil. Rather, they were intended to be grown in living soil. Compost creates and sustains a living soil, so when grown in the proper environment as nature intended, the gene expression of plants is optimized for their health.
This concept also applies to humans. Humans were never intended to be sedentary bumps on a log. Studies show that proper exercise literally turns certain genes on or off and thereby affects our vulnerability to a host of diseases to a substantial degree. So the fact that environmental factors such as the presence of compost can have a large effect on the well-being of plants is not at all surprising. When humans eat right and get their exercise, the aggregate cost of health care is reduced. When plants eat right, the cost of their health care is also reduced. Just as a human in optimal health is more productive, a plant grown in soil amended with compost has greater yields.
According to the Washington State University Cooperative Extension Service (along with dozens of other sources), compost helps soil retain fertilizers better, and also reduces or even eliminates the need for fertilizer altogether. Fertilizer, like fungicides, costs money. WSU also states that the beneficial microorganisms in compost can help protect crops from pests, thereby reducing the need for pesticides. That’s even more money.
So right there, if you garden and your intention in gardening is to save money over buying an equivalent product at the grocery store, the case for using compost is open and shut—done. If you aren’t using compost, you are throwing money away.
Another reason to use compost is human health. Depending on which experts you ask, humans need anywhere from twenty-two to fifty elements in their diet for optimal health. I am not speaking of vitamins and other complex molecules, but rather basic chemical elements that we need in order to catalyze the synthesis of cellular enzymes or even as core constituents of structures such as bones. Though a person can survive and even thrive for a time with an ongoing deficiency in some of these elements, over time deficiency takes its toll, and some USDA researchers have come to believe that most cancer and as many as 50 percent of all deaths globally are caused directly or indirectly by insufficient intake of important trace elements.
Though this information has not been widely disseminated in an environment where other branches of the USDA continue to push nutritionally vapid commodities as “healthy”, it is available for those who care to search. In fact, long before the USDA researchers came along, Dr. Maynard Murray conducted numerous experiments demonstrating dramatically reduced risks of cancer and many other chronic diseases in animals fed foods grown in such a way as to contain as many elements as possible.
Many find it puzzling that in an era where preventable causes of cancer and heart disease are in decline, many other forms of cancer and heart disease are increasing. But taken with the information above, it might not seem so surprising once we realize that the elemental content of agricultural soil has declined by 85 percent over the past 100 years and the nutritional content of commercially available foods has declined by anywhere from 30 percent to 81 percent over the past thirty years.
So the elements in the soil you use for growing food are important. The full complement of elements is certainly important for the well-being of your crops, and assists them in fending off pests and diseases through their own robust immune systems. But the elements in your soil are also important for the well-being of the people who eat those crops, including you.
Standard agricultural methods can be described as having mined all the nutritionally necessary minerals out of the soil. Those methods return a handful of elements in the form of fertilizer, but only thirteen elements are generally required to grow a good-looking and marketable food commodity in a competitive market that doesn’t distinguish one tomato from another. All of the other elements needed for human health— elements that were abundantly present a century ago—are either absent or severely depleted.
Compost contains and preserves these micronutrients that are so important to human health. So if you grow a garden for your health, you really need to use compost otherwise you are largely wasting your time.