How to Preserve a Halloween Jack o Lantern

Tips To Make Your Halloween Pumpkin Last

Keep a carved pumpkin looking its best all season.
Keep a carved pumpkin looking its best all Halloween season with a little help from chemistry. Gail Shotlander/Moment/Getty Images

Your carved pumpkin or Halloween jack o lantern doesn't have to rot or mold before Halloween! Here is how to use chemistry to preserve a jack o lantern so that it will last for weeks instead of days.

How To Preserve a Carved Pumpkin

  1. Mix up a preservative solution for your carved pumpkin consisting of 2 teaspoons of household bleach per gallon of water.

     

  2. Fill a sink, bucket, or tub with enough of the bleach solution to totally immerse the carved jack o lantern. Place the jack o lantern in the bleach mixture right after you have finished carving it. Soak the carved pumpkin for 8 hours or overnight.

     

  1. Remove the pumpkin from the liquid and allow it to air dry. Spray the pumpkin inside and outside with a commercial pumpkin preservative or use your own mixture, consisting of 1 teaspoon of bleach in water. Spray the pumpkin once daily, to prevent the growth of bacteria and mold.

     

  2. Smear petroleum jelly on all of the cut surfaces of the pumpkin. This will prevent the pumpkin from drying out and getting that puckered, shriveled look.

     

  3. Protect the jack o lantern from sun or rain, since one will dry the pumpkin out, while the other will promote the growth of mold. If possible, refrigerate your jack o lantern when it's not in use.

How Pumpkin Preservation Works

Bleach is dilute sodium hypochlorite, an oxidizer that kills microorganism that decay the pumpkin, including mold, fungi, and bacteria. You need to reapply it because it loses its effectiveness fairly quickly. The petroleum jelly locks in moisture so the jack o lantern doesn't get dehydrated.

Now that you know how to keep it fresh, make a science Halloween jack o lantern.

More Tips to Preserve Pumpkins

  • Another way to make a pumpkin last is to simply wait until it's closer to Halloween to carve it. One idea is to mark the carving for the big event, but not actually cut it. Then coat the entire pumpkin except the areas to be carved with glow-in-the-dark paint. This gives you a glowing pumpkin with dark areas where the carving will go.
  • While bleach reacts with air so it needs to be re-applied, you can get lasting protection against critters and mold by treating a carved pumpkin with borax. You can either sprinkle borax powder around the interior of the jack o' lantern and the carved surfaces or you can dip the pumpkin in a solution of borax in water.
  • Another good tip is to use care when selecting your pumpkin. If you can, try to select a pumpkin that is fresh and firm. A freshly cut pumpkin won't have a shriveled stem or soft spots anywhere on the fruit. You have a much better chance of keeping a pumpkin until Halloween if it doesn't have an established colony of bacteria and mold.
  • When you carve the pumpkin, clean the inside as well as possible. If you leave any strings or seeds, you'll providing extra surface area for microorganism growth. It's easier to keep a smooth surface clean than a rough one.