Decomposing Pumpkin Activity

What to do with that jack-o’-lantern once Halloween is over? Why not set it in a corner of your yard for a science activity about making observations and the circle of life?

What you need:
• pumpkin
• area of ground outside where the pumpkin can decompose
• pen
• colored pencils and/or digital camera
• science journal

What you do:
• Put either your jack-o’-lantern or another pumpkin you are done with in a corner of a yard where it can rot freely.
• Help your child record the starting date and then draw or take a picture of the pumpkin at the beginning of your experiment. Have your child write some notes recording his or her observations about the pumpkin at this moment.
• Make weekly observations of the pumpkin over the next several months. Continue to observe it until it has rotted away to the ground. During each visit, have your child take or draw a picture and write notes.
• From time to time, discuss the changes you are observing and have your child make suggestions about why these things are happening to the pumpkin.
• Alternate versions: Observe both a carved and an uncarved pumpkin decompose (and compare differences in the ways and rates at which they decompose) or, if you have no place to let a pumpkin rot outdoors, watch a piece of pumpkin in a glass jar rot inside.

What you can talk about:
• Explain that the pumpkin is rotting because bacteria, fungi, small insects, and other decomposers are breaking it down into tinier parts.
• Note that seeds are left behind to grow more pumpkins.
• Explain that as the decomposers turn the pumpkin into tiny bits, they make nutrients that enter the soil and turn the soil into a great place to grow more pumpkins. Rotting old plants provide food to grow new ones.

Literature Links
• Pumpkin Circle: The Story of a Garden by George Levenson contains a good series of photographs chronicling the decomposition of a pumpkin.
• Pumpkin Jack by Will Hubbell tells the story of a boy who watches his jack-o’-lantern rot away after Halloween and leave behind seeds that sprout the next spring and grow into new pumpkins, one of which the boy carves into a new jack-o’-lantern.