Homeowner issues PSA after stacked mulch bags catch fire in hot, dry weather

A stack of discounted mulch bags sitting beside a garden might not seem especially dangerous, but one homeowner's close call shows how quickly that can change in summer weather.

In the PSA story shared on Reddit, a home gardener explained that during a stretch of heat, drought, and wind, the stored bags of mulch caught fire, and the home was reportedly only saved because a neighbor was home and noticed what was happening.

The homeowner on Reddit said firefighters mentioned to them that incidents like this "happen pretty frequently because the plastic bags act as a magnifying glass right over top of the wooden mulch." 

The house did not burn, but the fire still took a toll. In the comments, the original poster noted that it charred her 10-year-old rosemary plant, destroyed the chives, burned a tomato plant and Russian sage, and partially melted the home's siding.

The discussion in the comments turned to what likely started the fire, with many users arguing that the danger came from heat building inside decomposing organic material rather than from the plastic concentrating sunlight. 

One wrote: "No plastic bag can act as a magnifying glass. This is because of all the bacteria and microbes decomposing the wood combined with the sun and the bag holding heat in. Same thing happens with hay stacks and compost piles."

Another added, "We had a neighbor almost lose his garage when a too-deep pile of mulch spontaneously combusted due to composting heat."

Buying mulch when it goes on sale and leaving it stacked until there is time to spread it is a common summer habit. But in hot, dry, and windy conditions, ordinary yard supplies can turn into a fire hazard.

"Thanks for the PSA," one commenter wrote. Other commenters also appreciated the PSA with one adding, "Oh dang, I have like 8 bags laying flat in the sun (as temporary grass killers), thanks for the heads up!"

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