Updated Oct 28, 2022
Not sure what to do with your jack-o’-lanterns after Halloween?
Instead of chucking old pumpkins in the trash, aim for the compost bin instead. Like other vegetable scraps, pumpkins are compostable. Leftover peelings, rinds, and cores are ideal composting materials because they break down quickly and easily, developing into nutrient-rich fertilizer.
Composting helps more than just your garden plants – it’s an excellent way to keep food waste out of landfills.
According to the U.S. Green Chamber of Commerce, nearly 1.3 billion pounds of pumpkins end up in landfills each year. In landfills, food waste like rotting pumpkins emits methane, a greenhouse gas capable of depleting the ozone layer and contributing to global warming. Adding this waste to a compost pile provides a controlled environment for the scraps to decompose into a biodiverse concoction perfect for healthy plant growth.
You shouldn’t use rotten pumpkins for decorations and baking, but don’t hesitate to add them to the compost pile. Moldy pumpkins are teeming with microorganisms beneficial to the composting process. These tiny fungi and bacteria are expert decomposers, helping to speed up the decay process needed for rich compost.
You may not want to bake old pumpkins into a pie for your family, but you can still keep them from going to waste. We’ll show you how to compost leftover pumpkins in three easy steps. You’ll keep yard waste out of landfills and have nutrient-dense compost to show for it.
The first step to composting decorative pumpkins is to remove any candle wax, ribbons, glitter, or paint. Paint, glitter, sealants, and wax won’t decompose in your compost pile. The chemicals in these decorations can contaminate the natural components of the pile, producing a harmful batch of fertilizer.
If only part of your pumpkin is painted or decorated, you can remove that section or scrape off the top layer of skin. The goal is to include only organic matter in your compost.
Next, clean the inside of the pumpkin. Remove all the pumpkin seeds to keep your compost bin from sprouting new plants. This part may already be done if you carved your pumpkin as a jack-o’-lantern.
Seeds are natural and won’t harm your compost, but they may start growing new pumpkin plants where you don’t want them. If you’d like some seeds to plant next year, remove them from the pumpkin, wash off the pulp, and let them dry on paper towels for a few weeks. Then, store them in a paper bag until the next planting season comes around.
Once you’ve cleaned up your pumpkin, it’s time to get smashing. If your pumpkin was already rotting on its own, this step will be easy.
Pumpkin flesh is rather tender and will break down easily. On the other hand, the rind is a thick, hardy material that will take weeks to decompose if left whole. Instead of throwing a whole pumpkin straight into the compost bin, chop (or smash) it into smaller pieces to speed up decomposition.
This step can be a fun way to teach kids about decomposition. Let them throw the old pumpkin off a balcony and watch it crash to the ground. Or, turn it into a competition and see who can throw their pumpkin farthest. If all else fails, throw on rubber boots and have a pumpkin stomping party. When you’re done, you’ll have bite-size chunks for microorganisms to munch on.
The final step is to add your pumpkin to your compost pile. We recommend mixing the pile with a rake or shovel after adding the chunks. A good stir will incorporate the fresh scraps into the hot, steamy parts of the pile that are already busy decomposing.
New to composting? No problem.
The UCCE Master Gardener program provides the following steps for starting a compost pile:
Backyard composting isn’t the only way to use leftover pumpkins. Here are some other ways to get rid of your gourds:
Uncarved pumpkins are edible for eight to 12 weeks after they’re picked. This means you may be able to put that decorative pumpkin to good use in the kitchen. This article from Splendid Table serves up four ways to cook decorative pumpkins.
Cut the pumpkin into chunks and leave it in the woods for critters like raccoons, squirrels, and birds. If you want to avoid attracting wild animals to your yard, see if a local farm will take your scraps. Animals like cows, pigs, horses, and goats will love to snack on some crunchy pumpkin rinds.
Drop off your leftovers at a community compost program or recycle center. These centers help communities manage food waste with minimal environmental harm. This guide from Good Start Packaging can help you find a composting service center near you. You can also look for a Pumpkin Smash event to ensure your pumpkins are composted instead of tossed in a landfill.
Pumpkins are charming fall decorations that happen to be wonderful composting materials. If the spooky season ends or you start noticing a little mold on your jack-o’-lanterns, you can dispose of them in an earth-friendly manner that’s beneficial to your garden. You’ll keep food waste out of landfills and produce a homemade fertilizer, all while cleaning up your space for the exciting seasons to come.
Other Lawn Resources