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Peat moss soil amendment, made of partly decayed, dried sphagnum moss (By Ragesoss (Own work) [CC-BY-SA-3.0-2.5-2.0-1.0 ( or GFDL (], via Wikimedia Commons)


Peat is the partially decomposed remains of plant material, especially sphagnum moss. It is found in a wetlands environment where the addition of new plant material is faster than the decomposition of the accumulated plant material. A number of essential conditions that contribute to peat formation is provided in a wetlands: the plant material remains waterlogged, the temperature is low and there is a lack of oxygen both of which slow decomposition. “Wetlands” include floodplains, marshes, swamps, and coastal wetlands.

Peat is the first material formed in the process that transforms plant matter into coal. As coal formation progresses, volatile materials like water are driven off, and the percentage of carbon content of the material increases, making it increasingly dense and hard.

The majority of the peat harvested is called reed-sedge peat. The other harvested forms are sphagnum moss, humus and hypnum moss.


The word peat has its roots in the Old Celtic root word pett- meaning piece in reference to a piece of peat that had been cut from a bog.


In the United States, Florida, Michigan, and Minnesota are the leading producers of peat, although 20 of the contiguous states and Alaska produce peat. The United States is estimated to have 110 billion tons of peat, and approximately one-half of it is in presently undisturbed areas of Alaska.

Of the peat that is imported into the United States, most comes from Canada. Other significant producers of peat are Belarus, Estonia, Finland, Germany, Sweden, Lithuania and Russia. It is estimated that world resources of peat are 2 trillion tons.


caption A small chunk of peat. (Source: University of Wyoming)

Approximately 95% of the peat consumed is in agriculture and horticulture for soil improvement (peat retains large amounts of water and liquid fertilizer), potting soils, for earthworm farms, and golf course maintenance. It is also used for other gardening and agricultural applications such as packing plants and growing mushrooms and vegetables. In some parts of Ireland, peat is burned in fireplaces to heat homes.

Because peat is so absorbent, it is used in industry to absorb oil spills. This same quality makes peat a good material to filter contaminants from water. Peat has also been used as a sterile absorbent in such products as diapers and feminine hygiene products.

Substitutes and Alternative Sources

Natural materials (leaves, plants, vegetable matter, etc.) can be composted. These materials compete for some peat applications (improving soil, for instance). But most products do not match the superior absorbent qualities of peat.

Further Reading



Disclaimer: This article is taken wholly from, or contains information that was originally published by, the Mineral Information Institute. Topic editors and authors for the Encyclopedia of Earth may have edited its content or added new information. The use of information from the Mineral Information Institute should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content.




Institute, M. (2014). Peat. Retrieved from


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