Bagged or baled peat is a regular offering at most garden centers, but in recent years, more attention has been paid to how this soil is unsustainably extracted from the earth.
Peatlands—also called bogs or mires—are unique and vital water-saturated habitats that house a number of threatened species: Acidic-soil lovers, like carnivorous plants and heathers, are among them. Like forests, peatlands are carbon-sequestering sinks, often hosting thousands of years of successive layers of low- and slow-growing plant deadfall, as well as sphagnum moss.
When peat is harvested in strips for use in the garden (or worse, for use as fuel), these delicate biomes that have taken eons to form are irreparably damaged. In building gardens that require low pH or high-organic-matter soil, consider a number of sustainably produced alternatives to keep the integrity of these non-renewable ecosystems intact. Although these solutions require some experimentation, they provide the basic building blocks for rich organic soil.
Coconut coir is probably the best commercial peat alternative. It is a hardy plant fiber is a byproduct of coconut harvesting as a food crop, meaning it is a renewable material. It has the added advantage of normally being pasteurized and free from bacteria and spores of fungi.
Wood and Bark Mulch
Finely ground wood products are another peat alternative, providing a high-carbon, moisture-retentive boost to soil structure. Wood is also, in most cases, a super-local renewable material that can be harvested from normal garden maintenance, like pruning, which cuts down on the environmental impact of transport.
Biosolids and Compost
Both waste products (biosolids from sewage processing and compost from fermenting biodegradable food and household waste), these soil conditioners are also high-carbon additions to the soil. They require a bit of care and hygiene planning to use in the garden, but otherwise make a suitable peat alternative.