A Post-Halloween Trick: the Moldy Pumpkin

Nov 6, 2018

Each October, sights of carved pumpkins greet passersby on doorsteps and porches across the country. Ghoulish faces and spooky sayings illuminated by candles on bright orange gourd-like fruit are a sure sign that Halloween is just around the corner. In early November, however, drooping and discolored pumpkins still on stoops are a sure sign that Halloween has come and gone. So what causes a carved pumpkin to rot and how can you ensure this doesn’t happen to a jack-o’-lantern until after trick-or-treaters have filled their bags with candy?

Pumpkins, just like all produce, do have an expiration date. Once they are cut to be carved into glowing creations, this expiration date arrives even faster. Pumpkins typically soften and rot within a week after being cut, so keep that in mind when planning out a pumpkin carving session.


Emerson the Pumpkin (gone before his time…)

Emerson was taken by an unidentified rot

The ideal temperature for carved pumpkins is 50-55 degrees Fahrenheit. Warmer temperatures will speed up deterioration while freezing temperatures will slow deterioration. On the other hand, the cold will damage plant cells once the pumpkin warms up again, leading to the aforementioned softening and rot.

After they are cut, a lot of organisms like to reside on pumpkin flesh and break it down, including fungi, bacteria, mold and insects. Some of the top contenders for pumpkin destroyers are:

  1. Black rot: this is the most important disease contracted during the storage of pumpkins in the Northeast. Affected fruits might show lesions of black rot or collapse soon after harvest. Black rot typically appears as black specks in a ring pattern on pumpkins. Large Halloween pumpkins are more susceptible to this than smaller types for pies.

  1. Phytophthora blight: fruit that develop with phytophthora blight are typically undersized and distorted. White mold and fungus spores will develop on areas affected, which later become covered with a yeast-like growth.

  1. Sclerotinia white mold: pumpkins are particularly susceptible to this white mold. Decay is rapid and is characterized by rot that is watery and odorless along with an abundance of white cottony mold containing embedded black bodies of fungus. The rot can spread by contact from fruit to fruit.

While the outlook isn’t great for long-term survival of carved pumpkins, you can take some precautions to try to extend the stoop-life of your pumpkin for following Halloweens:

1) Pick a healthy pumpkin: choose a pumpkin that is fresh, healthy, and firm.

2) Get rid of all guts: make sure the inside is as clean and dry as possible before carving.

3) Use some petroleum jelly: apply a thin layer of petroleum jelly to the inside of your pumpkin to reduce mold and slow down decay.

4) Put your pumpkin in the refrigerator: if you are able to, placing your pumpkin in a refrigerator each night can go a long way in rehydrating your carved fruit as well as keeping it away from bugs and critters.

5) Soak overnight: another rehydration method is soaking the pumpkin overnight to keep it fresh. This is great to try if you notice that your pumpkin is beginning to wilt or fade. Make sure to use cold water as warm water can speed up the rotting process.

Hopefully staying informed about what can afflict pumpkins in addition to taking steps to prevent pumpkin deterioration will be more of a treat instead of a trick for the next Halloween. What was the best jack-o-lantern you saw this year? Do you have any good tips for keeping carved pumpkins rot-free longer for next year’s Halloween? Let us know in the comments section.

PathSensors’ Pumpkin Palooza

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