What happens when you let a pumpkin rot?   That was the question proposed by my son last year…so we decided to find out.

Pumpkin Science What Happens to a Rotting Pumpkin

Rotting Pumpkin:

We carved our pumpkin & put it on the porch to greet visitors. Rotty September 142

After a few weeks, our pumpkin, who Reese named Jack Rotty, began to get a little mushy.   We got a tray for Rotty to sit on so he wouldn’t rot directly onto the porch. We made a journal to record our daily findings. We got to work!

Rotty September 191

Halloween Activity: Journal

Friday, 6:00pm “Rotty is turning soft like a sponge. It’s got black mold. It’s getting eaten by a bug & looks black and not so good.”

Reese poked his finger into the mushy parts….
Rotty September 192 Reese
Each day, Mom recorded Reese’s observations. I drew the outline of Rotty & Reese colored in the mold spots & mushy parts.   If you have an older child, let them do the recording & drawing.
Rotty September 194

September 13

Saturday, 6:00pm
“Where I stuck my finger it grew mold. The back is all fuzzy moldy. It has bugs. More mold is growing inside. I can’t believe where I stuck my finger got mold!”

Rotty September 227


September 14

Sunday, 7:15pm

Rotty September 238 Reese“It’s rotten. It looks kind of ashy. His mouth is getting all rotten. I see a spider on the pumpkin. There is more mold today. I see bugs. They must be looking for food in Rotty. He feels soft.” Rotty September 242


September 15 Monday, 6:30pm “He’s rotten & smells like a dirt pile. His face is all gooey. You can see where I stuck my finger in. Look at all the pumpkin juice! The back is falling & tipping over. I wish Rotty would stay a little bit longer. His color is black & orange.” Rotty September 305


September 17 Wednesday, 7:15pm “He is rotten. He is smaller because he’s going down. Inside there’s a lot of mold! It smells like pumpkin to me…and dirt. I don’t see any bugs today. There’s a soft part on his head.” Rotty September 339


September 21 Sunday, 7:15pm “He’s so small! Not big & bumpy. You can still see where I put my finger. He’s decomposing. Part is soft from decomposing, but part is hard because it dried up. There’s a fly on him. He must eat the pumpkin. The back is sinking fast!” Rotty September 305


September 22

Monday, 7:30pm “He’s not like that anymore…not full. He looks like rotten eggs. He’s all brownish. Look inside…mold! He is small. I see a Junebug in there…it’s laying in Rotty. I see a fruit fly inside…lots of fruit flies!”

Rotty September 498


September 26 Friday, 3:00pm “He’s not big & tall. He feels hairy. He’s dry. It’s called evaporate. Our guess was wrong. I thought he would turn into goo. We see fruit fly larva from Larva Land. No, really, they came from fruit flies.” Rotty September 532September 530September 537

Pumpkin Faces:

We loved watching how the face of Rotty got grumpier and grumpier as it aged.   This was a GREAT experiment to do together. It was Reese’s first chance at long term observation, and our record book helped keep track of the changes each time we looked. I had to put a note on Rotty that said “Please excuse our science experiment!” because I was afraid our dear UPS lady would think we’re nuts!

How do you decorate your pumpkins?



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28 Comments

  1. Hello just wanted to give you a quick heads up and let you know a few of the images aren’t loading properly. I’m not sure
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