Peat moss if formed by the slow decomposition of mosses, like sphagnum, or sedges in a wet, acidic environment such as aquatic bogs. Peat is mainly produced in Europe or Canada, although production in China is starting to develop. Peat is the main component in many potting mixes that are readily available and widespread.
Advantages:
Peat moss has high porosity, good water holding capacity, and is readily available.
Disadvantages:
The low pH, typically less than 5.5, means it must be amended prior to planting for most plants. Most peat is not sterilized, so plant pathogens can be an issue depending on source of material. Peat has good water holding capacity, but because of peat’s particle size it does not have very good aeration.