Peat moss, a common organic ingredient in potting soil and soil conditioning products, presents a fire hazard under certain conditions. Gardeners prize the ability of peat moss to hold moisture for use by plants. The presence of peat moss in planters and flower beds provides a flammable medium in many homes which may not be considered until a fire begins.
With an ignition temperature of 500 degrees Fahrenheit, dry peat moss provides a safe soil conditioner under most conditions. (see reference 2) Fire most often occurs when an outside heat source makes contact with the peat. For example, a discarded cigarette butt generates temperatures in excess of 700 degrees Fahrenheit, Smokers should avoid discarding butts in planters.
Home and apartment fires which begin in planters can burn unnoticed for several hours. Peat smolders rather than bursting into flame and can burn down to the base of the container with no more evidence than a thin smoke plume and pungent odor. Any flammable materials near the container can help spread the fire. Decks and other wooden structures present a rich source of fuel.