If you’ve ever left a jack-o’-lantern outside for a week or two, you might have noticed black blotches on its skin. These are produced by tiny organisms, like bacteria, that feed on the pumpkin. The grinning head shrinks and shrivels. That’s because pumpkins are 90 percent water. As the fruit decomposes, the water slowly evaporates, or turns from liquid into gas.
After Halloween, many Americans toss their pumpkins in the trash. Each year, 650,000 tons of pumpkins end up in landfills. The gourds are buried under garbage. When food and plant-based waste decompose underground without any oxygen, bacteria release a gas called methane. The gas stays in Earth’s atmosphere, trapping some of the sun’s heat and contributing to climate change.
That’s why groups like SCARCE collect pumpkins. After the events, the smashed fruits are brought to facilities where they’re shredded and left in piles (see Gourd to Ground, below). Workers regularly flip the piles so that bacteria have oxygen and don’t release methane. This process is called composting.
After about six months, the pumpkins turn into a material similar to dark soil that is rich in nutrients. When it’s added to gardens, it helps plants grow!