Once your pumpkins have finished their season on the porch, the compost pile is one of the best places for them to go. Our post on what to do with your pumpkins after Halloween covers the basic choices. This one is for people who have decided to compost and want to do it well, so the pumpkin turns into good soil instead of a soggy mess.
Start with a clean pumpkin
Composting only works with things that break down. Mississippi State University Extension says to remove any candles, wax, paint, stickers, or anything else that is not natural before a pumpkin goes in the pile. A Mississippi State Extension garden column goes further and says not to compost pumpkins that have paint, stickers, or other decorations on them. Fairfax County Master Gardeners, who are trained through Virginia Cooperative Extension, add that any decorating material should be nontoxic before you compost. Check inside carved pumpkins for battery lights and wax drips.
Chop it into small pieces
A whole pumpkin has a tough rind that slows everything down. Mississippi State Extension notes that pumpkins compost faster when they are broken into small pieces, and the Fairfax County Master Gardeners suggest chopping them up with a shovel and mixing the pieces into the pile. University of Arkansas Cooperative Extension explains why this helps: smaller materials have more surface area and decompose faster. University of Illinois Extension adds that smashing pumpkins helps them start breaking down before they go in the pile.
Balance the wet pumpkin with dry browns
Pumpkins are mostly water, about 90 percent according to Ohio State University. In compost terms they count as a wet, nitrogen rich green, and a pile of nothing but pumpkin will turn slimy. University of Arkansas Cooperative Extension lists kitchen waste as a green and fall leaves as a brown, and suggests a pile that is about one quarter to one half greens and one half to three quarters browns. University of Georgia Extension suggests roughly one third greens and two thirds browns. NC State Extension recommends mixing pumpkin pieces into the pile with browns like dried leaves, which most yards have plenty of in November.
Moisture matters too. Both Arkansas and Georgia Extension describe the right feel as a damp, wrung out sponge. Georgia Extension says to add dry browns if the pile is too wet, which is the usual problem after a few pumpkins go in.
Decide what to do with the seeds
The Fairfax County Master Gardeners advise removing the seeds before composting, and they note that pumpkins left whole in a garden can give you volunteer plants the next year. University of Georgia Extension says a pile needs to reach about 145 degrees Fahrenheit to destroy weed seeds, and many backyard piles never get that hot. If you would rather not have surprise pumpkin vines in your garden beds next summer, scoop the seeds out first and roast them or set them out for birds.
Turn it and give it time
Air keeps a compost pile working. University of Arkansas Cooperative Extension calls oxygen critical and lists turning as a way to add it, and University of Georgia Extension says more frequent turning gives you finished compost sooner. Arkansas Extension says compost is finished when the pile no longer heats up after you turn it. Pumpkin added in November will not be ready right away, so plan on it being part of next year's garden soil.
No compost pile? Bury it
You do not need a bin to compost a pumpkin. NC State Extension suggests burying pumpkin chunks directly in garden beds, and University of Georgia Extension says that with trench composting, the rotted material becomes part of the soil within a few months. Ohio State University Extension wildlife specialist Marne Titchenell told NPR that composting is a good way to recycle pumpkins back into soil. If you have no space at all, NPR suggests asking whether a community garden will take them.
Questions about your pumpkins?
If you have a pumpkin question we did not cover here, we would be glad to help. Call or text us at (513) 409-0005, or send a message through our contact page. We are a family-run business right here in the Springboro, Dayton and Cincinnati area, and we are always happy to talk pumpkins.