What is sphagnum peat moss and where does it come from?

When you see a picture of a harvested Canadian peat bog, it looks like any other field that is made up of mineral soil. Actually, the tan-brown peat moss that makes up the field is an accumulation of sphagnum moss plant residues; there is no mineral soil in a peat bog. Peat moss is used by professionals and consumers to make growing media or to incorporate into a garden or landscape as soil conditioner. The most common use for peat moss is for producing professional and consumer growing media to grow plants.

Most of the peat moss used in crop production comes from Canada and is composed mainly of mosses from the genus Sphagnum (of which there are 160 species of sphagnum found globally). This is where the name sphagnum peat moss is derived from. Sphagnum peat moss is valued by growers and gardeners because it is virtually free of weeds, insects and diseases. It also has a high water holding capacity with good air space, it is consistent from year to year, and crops thrive in it.

Canadian peatlands formed over 10,000 years ago in very moist and poorly drained low spots such as old river beds, lakes or ponds. Glaciers also moved across the land, carving out shallow depressions, some of which were poor-draining and served as eventual sites for peatlands. After the glaciers melted, the water runoff filled in these areas. Due to their poor drainage, the water has low oxygen, so it is anaerobic and has limited microbial populations that would normally decompose plant material. In a typical peatland, the rate of decomposition of dead plant material is very slow compared to the rate of accumulation, allowing dead plant material, known as peat, to accumulate.

Read more at PRO-MIX (Troy Buechel)