Tips for composting your post-Halloween pumpkins
With a bounty of leaves falling from the trees, autumn is the perfect time to start making compost. “It’s a powerful, free, totally natural way to improve conditions for your plants,” said Sharon Yiesla, plant knowledge specialist in the Plant Clinic at The Morton Arboretum.
What is compost?
“It’s just dead plants that have been partially broken down by the same processes that have been improving soil for millions of years,” Yiesla said. “In nature, it’s a thin layer on the top of the soil called humus. When we make it in a pile to use in our gardens, we call it compost.”
Compost added to the soil helps plants grow by increasing its organic matter and loosening the texture so water drains more freely. It will increase the populations of healthy soil organisms that provide critical chemical nutrients to the roots of your living plants. “If you keep dead plants in your garden and turn them into compost, the nutrients they built up when they were alive will eventually help your other plants,” Yiesla said.
The actual work of breaking down dead plants is done by a wide variety of living things, including bacteria, fungi, microscopic nematodes, arachnids, centipedes and earthworms. “You give them plants to eat and they’ll give you compost,” she said.
Here are some tips from Yiesla to help you start composting or improve your existing pile’s productivity.
Start with leaves: Leaves, like all dead, brown plant matter, are rich in carbon. A compost pile should include carbonrich plant materials as well as nitrogen-rich ones — fresh, green things, such as weeds you’ve pulled, end-of-season annuals and vegetable scraps from the kitchen. “If you can, stash extra leaves away in autumn so you have carbon-rich material to add all year,” Yiesla said.
Add a bit of soil: Compost is created by natural soil organisms. Help them find your pile by tossing in a shovel full of soil from your garden. From then on, the composters will reproduce as long as they have a food supply. There’s no need for products marketed as compost starters, inoculants or accelerators.
Use mostly yard waste: Your pile should consist mainly of plant matter from your garden. It’s OK to include some kitchen waste, such as coffee grounds and the cores and peels of fruits and vegetables, but never add meat, fat, oil, baked goods or animal waste.
For details on what to put in the compost and other advice, see mortonarb.org/ composting.
Big pile, smaller pieces:
A larger pile will hold in more warmth and moisture and its materials will decay faster. Aim for a pile that is at least 3 feet high and wide. When you add big things, such as branches or post-Halloween pumpkins, cut or break them into smaller pieces to decay faster.
Consider a bin: Many municipalities require compost to be contained in a bin to deter animals, and it can be nicer to look at than an open pile. You can make a bin or buy one. Be sure it’s well-ventilated so the composting organisms get the air they need.
Air it out: Turning over the materials from time to time will improve the air supply to the busy composters and distribute them more evenly. “It’s not essential, but it can help your compost break down faster,” Yiesla said. An open pile is easy to turn over with a garden fork. Turning compost inside a bin is more awkward, but even poking holes into the center will admit some more air.
Keep it moist: The composters need water as well as air. The material in the middle should be about as moist as a wrung-out sponge. Make sure a bin’s lid admits rainwater, and when there’s no rain, water the compost pile occasionally just as you would water your garden plants.
Harvest when ready: After three to four months, check the center of the pile. Compost is ready to use when it is dark brown and crumbly, with a rich, clean, earthy smell. “There will always be chunks that haven’t broken down much,” Yiesla said. “Just toss them back into the pile to keep working.”