Much of the work of carving a pumpkin involves separating the fibrous strands and seeds inside it from the harder pulp that makes up the pumpkin’s walls. As you scoop out the pumpkin’s innards, thoroughly inspect the inside walls for soft rotten patches or dark tissues, which may have been colonized pre- or post-harvest by bacteria, fungi or water molds. Diseased pumpkins sometimes produce an off-putting smell, so use your nose as well.

If you find these issues as you carve, you may want to try carving another pumpkin. You can also paint your pumpkins instead of carving them, which averts the need to peer inside.

Some online tutorials and YouTube videos recommend thinning out pumpkins’ walls to better allow candle or LED light to pass through. But if you make the walls too thin, your jack-o’-lantern’s fangs will become inward-curving skin tabs as the pulp desiccates and deforms. A toothless jack-o’-lantern scares no one.

Another advantage of maintaining thicker walls is that it enables you to try a 3D carving. This involves shaping the pumpkin’s surface as you would carve a piece of wood, without breaking through the shell, and can produce dramatic results.

Some people soak their carved pumpkins in diluted bleach or vinegar water after completing them. But this technique is a double-edged sword: Adding more free moisture to your masterpiece invites windblown mold spores and rain-splashed bacteria to colonize it. However, applying a light coating of petroleum jelly or vegetable oil to all the exposed parts can extend the shelf life of your sculpted squash.

October is a wet month with frequent rains in many parts of the U.S. Rain falling on your jack-o’-lantern will invite every mold in the neighborhood to take up residency in or on it. For this reason, I recommend keeping your pumpkins on a covered porch or displaying them from indoors in a window.

It’s OK if some mold forms inside it, as not all fungi cause soft rots – diseases that produce wet spots that spread, become mushy and turn black. If a pumpkin does become overly moldy on the inside walls, move it outdoors to avoid producing a lot of spores in your home.

When your pumpkin does start to mold and collapse, don’t throw it in a landfill. Put it out for your neighborhood deer or atop your compost pile. Or find a spot in your yard where you can watch it degrade over time, until it turns back to soil in time for next year’s pumpkin patch.

This article is republished from The Conversation, an independent nonprofit news site dedicated to sharing ideas from academic experts. It was written by: Matt Kasson, West Virginia University. If you found it interesting, you could subscribe to our weekly newsletter.

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Matt Kasson receives funding from the National Science Foundation, The National Geographic Society and the U.S. Department of Agriculture. He is an active member of the Mycological Society of America and the American Phytopathological Society.