The soil used to grow potted plants and fill raised beds appears to be excellent. However, it conceals some troubling issues for the environment and our health. All of those bags at the nursery are dirt-free sterile mixtures of exotic mosses, fibers, and minerals, components that conceal lung illness, water waste, and a colossal carbon footprint.
So why do we use it at all?
The number of urban gardeners has increased by 30 percent in last 30 years, and nurseries and greenhouses are the two fastest expanding agricultural enterprises in the United States. This has increased the demand for potting soil’s key ingredients: vermiculite, sphagnum peat moss, and coconut coir, all of which pose environmental and human health risks.
For instance, vermiculite, which is appreciated in horticulture for its popcorn-like texture, is mined and then roasted at temperatures above 1000 degrees Fahrenheit into the light crumbs seen in potted plant’s soil. However, the deep, open pits, heavy machinery, and propane-powered production plants have a negative impact on the environment, as can asbestos-contaminated vermiculite, on human health.
Similarly, most popular alternative to peat is coconut coir, which must be repeatedly soaked and rinsed during processing. Once the dehydrated coir bricks arrive at their destination, they again require large amounts of water for rehydration, all this result in hung amount of water wastage.
However, to make this more environment friendly we have options ranging from corn stalks to peanut hulls, nettles to yucca, beach grass to recycled cardboard, there are many things that can be recycled into growing media.
Reference- National Geographic, Horticultural Substrates Lab, Yale Carbon Containment Lab, Wikipedia, BBC Earth