Pumpkin Composting + Soil Sustainability Science Experiment

Don’t throw away your pumpkins after Halloween. Try this simple pumpkin composting sustainability science experiment for kids to learn about soil and recycle the pumpkin for the planet.

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Composting is everywhere. It’s starting to show up in some pretty mainstream places. Just during the last couple of months, two teachers at my boys’ school have asked about educational resources related to composting for their classes. Individual and organization interest in composting is rising quickly, which is great!

Composting is easiest when incorporated into your lifestyle, and it feels second nature. I’m thrilled to see students exposed to composting at young ages so they’ll know nothing other than this responsible method of waste disposal. Surely, they won’t think it’s gross if it is a standard part of their school lunch experience.

In one particular case, my son’s teacher asked about composting pumpkins in the fall. You may already know that we throw away billions of pounds of pumpkins in the aftermath of Halloween each year. Isn’t it crazy that we grow billions of pounds of delicious and nutritious food just to throw it in the trash?

If you can eat your pumpkins after Halloween or fall decorations, go for it! Bake ‘em. Roast ‘em. Saute ‘em. Toast ‘em. For all the pumpkins you can’t eat after Halloween, however, composting is one of many great ways to recycle pumpkins instead of throwing them in the trash.

After a little brainstorming, my son’s teacher and I (with the help of my RGK co-founder Jess) devised a simple sustainability science experiment to examine the impact of pumpkin decomposition in soil. My son is a second-grader so most of the students in his class are 7 and 8 years old. We designed this little experiment to be suitable for their age while spanning the school year to provide comparative soil assessments in the fall and spring.

Pumpkin Composting and Soil Science Sustainability Experiment for Kids

This sustainability science experiment shows young learners how burying their Halloween pumpkin in the soil and allowing it to decompose over several months creates soil with higher levels of biodiversity and a healthier soil ecosystem. Although the experiment does not simulate full composting with a variety of organic matter, it demonstrates how organic matter breaks down over time the same way it would in a fully functioning compost pile.

Instead of throwing your pumpkin in the trash, find a location to bury two pumpkins twelve inches under the ground that you can revisit several months later. Gather up your materials and start this hands-on sustainability project for kids. Even though it’s especially relevant in the fall, you can try this any time of year if you have pumpkins (or any type of squash) that are too ripe or rotten to eat.

Pumpkin Composting Materials + Tools

• 2 pumpkins, one whole and one broken into pieces
• thermometer
• small shovel
• ruler
• 3 coffee filters (for each of the fall and spring measurements, so 6 filters total)
• microscope (optional) – we recommend this microscope that comes with slides and coverslips
• slides and coverslips (to go with the microscope) – we recommend these slides and coverslips if you don’t have them already
• camera (optional)

Pumpkin Composting Experiment Instructions

We’ve separated the instructions into two sections. First, you’ll find the steps to take to set up the experiment in the fall. Then we’ve included the steps to perform in the spring when young learners can compare the soil sites and analyze their findings.

Fall

• Choose an area of soil and divide it into three sections: one to keep bare as a control, one to bury a whole pumpkin, and one to bury a pumpkin broken into pieces.
• Mark each location so you can find it in the spring.
• Dig a hole 12 inches deep in each location large enough to bury the pumpkins.
• Take a picture of the soil in each hole.
• Measure the temperature of the soil in each hole.
• Record the presence of living organisms in each hole.
• Take two small samples of soil from each hole. Place one sample from each hole on a coffee filter. Reserve the other soil sample from each hole to view under a microscope.
• Record your observations and answer the questions on the following worksheets.

Spring

• Return to each of the three locations and dig 12 inches down into the soil.
• Repeat steps 4 – 8 from above (Fall ) and analyze how the soil is the same and/or different from the soil observed in the fall before the pumpkins were buried.
• We also created a pumpkin composting and soil science activity workbook to go along with this experiment. The workbook includes follow-up questions to help your young learners document their observations and draw conclusions from the results. It also includes a fun writing project to connect with the pumpkins decomposition adventure over the coming months.

To purchase the workbook, head on over to our Teachers Pay Teachers account.

More Pumpkin Sustainability Science Activities

Want to extend your students’ learning and create a mini-unit centered around pumpkins? Check out our fun and simple pumpkin science activities, which include a free pumpkin life cycle printable, a read-aloud of the children’s book “From Seed to Pumpkin” by Wendy Pfeffer, as well as discussion prompts to engage your learners and recipes to avoid wasting any edible pumpkins!

If you try any of our pumpkin-related activities for kids, be sure to let us know how it goes. We love seeing our projects and experiments come to life in your classroom. Share and tag us at @RaisingGlobalKidizens on Instagram or Pinterest. Or send us an email with a photo and let us know how it goes!

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