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What Is Peat Moss?

By Milton Kazmeyer
A garden in progress
Image by Flickr.com, courtesy of Jon Bennett

Peat moss is a common horticultural soil additive, whose unique properties come from the specific conditions under which it is grown. With careful use, it can be a valuable addition to any gardener’s growing arsenal.


Peat moss is the common name for a variety of mosses from the genus Sphagnum, all of which can be found growing on and in peat bogs. The tough, fibrous moss increases the acidity of the bog on which it grows, as well as reducing airflow to the decaying matter underneath. This combination of factors has led peat bogs to preserve matter that would have normally decayed long ago, and many archaeological discoveries have been made underneath beds of sphagnum.


The tough, fibrous mass of peat moss can serve a variety of horticultural uses. When living moss is harvested and dried, it can become tough and water-resistant. You can plant biodegradable pots made from this material directly into the soil, and they naturally break down over a long period of time. More commonly, however, gardeners and landscapers use the moss when it is dead and partially decayed, where they often mix it directly into the soil for different purposes.

Soil pH

The most common use of peat moss is to lower the pH of soil for planting certain species. Mixing peat moss into a planting bed allows plants that prefer a more acidic environment to survive in soil that is otherwise more alkaline. You must take care not to overdo it, however; too much peat mixed into a planting bed can leave it too acidic for anything to thrive well.

Soil Composition

Another quality of peat moss is its ability to retain water. Mixed into dry or sandy soil, it can help reduce runoff and keep nutrients from leaching away. Likewise, if mixed into heavier clay soil, it can serve to lighten the consistency, allowing plants with more delicate roots a chance to find a firm foothold.


There are a few issues to consider when using peat moss. Living peat moss can harbor the fungal disease known as spirotrichosis, whose spores can enter the skin via cuts and abrasions. When utilizing living or dried peat moss, always wear gloves to prevent infection. In addition, the widespread harvesting of peat bogs for peat moss has been known to damage local ecosystems, so take care to ensure that your peat moss comes from a sustainable source.


About the Author


Milton Kazmeyer has worked in the insurance, financial and manufacturing fields and also served as a federal contractor. He began his writing career in 2007 and now works full-time as a writer and transcriptionist. His primary fields of expertise include computers, astronomy, alternative energy sources and the environment.