Lawn Bombs

Mowing your lawn can cause a fire

'HIGHLANDS RANCH – Now that spring is here, homeowners should be aware of grass fires that could start in an instant, but it is not the kind of fire you might be thinking about.

These grass fires can start with your grass clippings.

When many people mow their lawns, they take the clippings and bag them up, and it may be hard to believe, but that can be very dangerous.

"I kind of thought it was like an urban legend, waiting to see it on 'Mythbusters' or something," said Matt Garvin with Gilmore Construction.

Last Wednesday, a fire caused about $7,000 in damage to a Highlands Ranch home, and firefighters believe it was caused by mowing the lawn and the subsequent grass clippings.

"We hear a lot about spontaneous combustion," said Littleton Deputy Fire Marshal Tim Stover, but he says it's rare. "It's fairly unusual. We do see a couple of cases each year with grass clippings and mulch piles."

Stover says if you store your grass clippings in a bag or can, it can burst into flames.

"As it starts, it's a biological breakdown or decomposition of the material and it creates what's called a self-heating process," said Stover.

Stover says it is more likely to start if the clippings are moist.

"As the heat continues to build, materials drying sooner or later, that material is going to reach its ignition point," he said.

"I know that with like our painting rags and staining, that stuff will definitely do that," said Garvin.

Stover says to keep your grass clippings from catching fire you should not tie or cover them up.

"If you leave the container open or leave the bag open without tying it tight, it'll allow that heat to escape and that's what we need to avoid, is allowing that to stay confined into that area," he said.

Stover says the best thing to do is mulch your grass clippings and leave them on the lawn. If you have to bag them up, you should dump them out and let them dry out first because that will decrease the chances of a fire.'