Potting mix, called “potting soil” in the United States and “potting compost” in the United Kingdom, often contains no soil, no compost, and is not even always used in pots. Instead, the material farmers mix themselves or buy in bulk every winter is actually a sterile, soil-less mix of organic and inorganic materials meant to offer plants a perfect goldilocks place to put down roots. Depended upon by backyard gardeners, farmers, greenhouse and nursery growers, botanists, landscapers, foresters, conservationists, and biotechnologists, potting mix is a ubiquitous, quiet part of everyday life that is surprisingly exotic — made from mosses, fibers, and minerals that originate all over the globe, from Sri Lanka to India to South Africa, Greece, and Canada.