The Experiment

The purpose of this experiment was to test the effectiveness of various methods of preserving a carved pumpkin (jack o' lantern). We gathered some tips from various pumpkin carving resources, and also sampled a commercial spray. The results were observed over a two week period.

[...]

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.

Our Recommendations

Based on our findings in this experiment, we can confidently say that white glue is not an acceptable pumpkin preservative. Apart from that, we think the pumpkin preservation method you choose should be dictated by your goals and the nature of your jack o' lantern.

If you have an elaborate creation that you want to keep looking pristine for as long as possible, we recommend using either the bleach treatment or acrylic spray or hairspray (commonly used by expert pumpkin carvers). Your pumpkin's life may not be as long overall, but it will look good while it lasts. If you want to keep it looking OK for a week or less, Vaseline may suffice.

For maximum pumpkin life, Pumpkin Fresh spray seems to be effective for inhibiting mold growth and slowing decay. It is also expensive, at $4.95 per bottle plus shipping (we went through nearly two bottles in two weeks, for a small pumpkin). Although the spray will extend your pumpkin's life, the carving will show some shrinkage and age externally. Another benefit of the spray is that it is nontoxic and biodegradable, which makes it more convenient to use than bleach, and means you can compost your pumpkin. Since one of the main ingredients of the spray is borax, it would be interesting to see how effective a homemade borax and water solution would be.