
A townhome in the northern Minnesota city of Hallock was destroyed by fire August 31, and now a deputy state fire marshall said the blaze was caused by a potted plant.
The plant, a mum, which had been discarded and placed in a trash bag next to the house, most likely spontaneously combusted. The fire spread to the Adamson Townhomes, destroying the dwellings of Kelly Mowry and Jeff Thompson. No one was injured in the blaze.
Many believe the spontaneous combustion of potted plants to be an urban legend, but occasionally fire investigators peg common house plants as the source of some house fires.
However, the makers of potting soil strongly dispute this, and maintain that it's all an urban legend.
In a prepared statement, the Miracle Grow and the Mulch and Soil Council said:
“As we understand the question, there is no scientific evidence that organic products in small quantities can generate sufficient heat for spontaneous ignition. There are several urban legends suggesting potted materials may be subject to spontaneous combustion; however, we have requested all sources to provide facts that substantiate such claims or remove the information from their website. To date, all claims have been removed due to a lack of any factual evidence of spontaneous combustion."
Yet, many fire state fire marshalls and other investigators disagree. It is rare but not unheard of, they say, to find evidence of combustion in the root ball of potted plants. And there have been confirmed cases.
In 2006, Wisconsin resident Ron Severson returned home from a weekend trip to discover that the plastic pot in which rested a begonia was melted. The plastic table it was sitting on was melted, too.
Severson sent the melted pot to the state’s Department of Agriculture, Trade and Consumer Protection, which determined that it was chemicals the plant's soil that produced the heat.
Many potting soil mixes on the market today contain flammable material such as shredded wood, bark and/or peat moss -- and little real dirt. Some potting soil mixtures may contain fertilizers which can accelerate fires.
That means putting out a cigarette in a potted plant is a very bad idea!
None of this means that everyone should throw out all of their indoor plants -- just keep them well watered, and don't use them for ashtrays.