St. Paul Fire Chief John Maczko said that the plastic pot, full of potting soil, was on a plastic table on the deck of a home in the Mendota Heights neighborhood, the St. Paul Pioneer Press reported. The right combination of heat and humidity caused the soil to get hotter to the point where it burst into flames.

"It is hard to believe, but our house is the all the proof you need," homeowner Dan Stoven said Tuesday. "The only miracle was that my daughter got out."

Stoven's 17-year-old daughter, Amy, was asleep in the basement. Three passersby alerted her to the fire.

Maczko said that once the soil began burning, the heat melted the plastic in the pot and then the table. When the burning pot landed on the deck, it set the wood ablaze.