So, it turns out that when you pick an already ripe pumpkin from your garden, carve it up and find seeds already sprouting, don’t expect Mr. Jack O’Lantern to last very long. Our little guy was literally growing mold out the mouth in 3 days.

A quick google search found a great article about what makes the best preservative at a site called My Science Project.

Summary of Results

  • White glue – Preserved pumpkin for 6 days. Profuse mold and rot.
  • Acrylic spray – Preserved pumpkin for 9 days. Profuse mold and rot.
  • Vaseline – Preserved pumpkin for 9 days. Profuse mold and rot.
  • Bleach – Preserved pumpkin for 10 days. Minimal mold, some rot.
  • Control – Preserved pumpkin for 14 days. Minimal rot, some mold.
  • Pumpkin Fresh – Preserved pumpkin for 14 days. Minimal mold, some rot.

Basically, the best pumpkin is a fresh pumpkin (one that I assume is not sprouting seeds), and that the commercial preservatives only seem to be slightly effective.

One interesting thing to note, is that Pumpkin Fresh does a similar experiment, the results after 14 days being the following:

So the thing to take away from all this is, don’t carve your pumpkin until just before Halloween if you want to put it out on the porch! Even at 2 weeks, most of the pumpkins are looking sad and a little gross.

Also interesting to note, is that while the bleach seems like a good alternative, it is obviously not environmentally friendly and you can’t really compost your pumpkin when you’re done with it. It looks like one of the main ingredients in Pumpkin Fresh is Borax. So maybe next year we’ll try some Borax and water solution and see if we can’t get Mr. Jack to stay a bit more mold free and he’ll still be able to end up on the compost heap when we’re done.