How to Keep Your Halloween Jack-o-Lantern Looking Fresh and Teach Your Kids a Little Science in the Process

Carving Jack-o-lanterns is a fun Halloween tradition. Whether you transform your pumpkin into an exquisite work of art or a sweet smiley face with triangle eyes, preserving your Jack-o-lantern from mold and mildew can be tricky. But here’s a Halloween treat of a hint: Jack-o-lanterns can be preserved for a short time with the help of a dilute solution of chlorine bleach.

Dunking Jack

The directions below are based on a recommended procedure found on the Clorox website for extending the “porch life” of your Jack-o-lantern.

  • After cutting the top of your pumpkin off, use a spoon to remove seeds and stringy fibers from the inside of the pumpkin and the underside of its top. (If you have one, a grapefruit spoon – with a serrated edge – is a great tool to help dislodge fibers.) Consider collecting the pumpkin seeds for roasting and snacking.
  • Rinse the inside and outside of the pumpkin with tap water.
  • Carve your Jack-o-lantern masterpiece.
  • In a 5-gallon bucket or a large sink, prepare a solution of 4.5 teaspoons of 6% bleach in 3 gallons of water.
  • Immerse your Jack-o-lantern into the solution and stir it around to ensure 2 full minutes of contact of every part of the Jack-o-lantern with the solution; remember to immerse the Jack-o-lantern top too. The Jack-o-lantern will float, so keep pushing it down with a spatula or your plastic-gloved hand to ensure full immersion.
  • Remove the Jack-o-lantern and its top from the solution and place them on newspaper or paper towels to dry.
  • Pour the bleach solution down the drain. (Once used, the solution will not last for a repeat treatment in a few days – a new solution will have to be made.)

Halloween Science

When the kids ask you why you are dunking their poor Jack-o-lantern in a bucket or sink full of bleach solution, seize the moment to impart a brief science lesson, complete with Halloween themes of decay and vampire-like attack. Here are your “talking points”:

  • Pumpkins, like all vegetation, decay slowly over time. Carving a pumpkin speeds up the decay process because:
    • You have cut into the fruit, exposing the inner “flesh” to oxygen in the air. Oxygen combines with some of the chemical substances in the flesh of the pumpkin, breaking them down chemically. [And, yes, pumpkins are classified as fruit because they have multiple seeds, which you will be confronted with in droves when you carve yours! They make a wonderful snack.]
    • In the process of cutting into the pumpkin, you have likely transferred bacteria from the outer surface of the pumpkin to the inner flesh (although there may be fewer bacteria as a result of your rinsing the pumpkin before carving). Those bacteria that “hitched a ride” on your carving knife assist in the decay process by “feeding,” vampire-like, on chemical substances in the pumpkin such as natural sugars.
    • Dunking your Jack-o-lantern into a solution of chlorine bleach helps destroy “vampire” bacteria and mold, thereby helping to preserve it a bit longer on the front porch. With any luck, and especially if the outside temperature does not run too high, your “treated” Jack-o-lantern will be in fine shape for Halloween. [Most chemical reactions run faster when the temperature rises; cold slows them down, which helps preserve the Jack-o-lantern.] Storing your Jack-o-lantern in the fridge for a few days is certainly an option, if you have the space!

Here’s to a fun-filled Halloween!
Linda F. Golodner is President Emeritus of the National Consumers League and Vice Chair of the Water Quality & Health Council.

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