Soil Your Undies Challenge

We soiled our undies for science!

The Soil Your Undies Challenge is a simple way to test soil biology/microbial activity.

Just bury a pair of 100% cotton underwear for 60 days and then dig it up to see how much has decomposed. If just the elastic remains you have healthy soil!

You can also bury 2 pairs in different spots and compare the results.

Find lesson and activity ideas to do your own Soil Your Undies Challenge here or more learning activities about soil here.

How does it work?

McLean County Ag in the Classroom sponsored a friendly competition among local FFA Chapters for the #SoilYourUndiesMcLeanCounty Challenge. Ag students buried 2 pairs of undies in 2 locations on their school grounds & then dug them up 60 days later.

Thanks to Olympia, Heyworth, Tri-Valley & Lexington FFA Chapters for participating! Check out the results of our experiments in the photos below.

Get the Dirt on Soil!

Dig deeper into the world beneath your feet and explore the science of soil with these resources & learning ag-tivities!

Soil Ag in a Bag

McLean County (IL) teachers can request FREE Beef ag mags and activity kits for their classroom: Click here

Online Reading Materials

Soil Ag-tivities

For more info:


Books to Read – set up a FREE account on to read these online books for FREE (for up to 14 days)!

Earth Day

For farmers, everyday is Earth Day – they work hard to protect our water, land & natural resources to be able to keep growing year after year. Learn more at

When it comes to our natural resources, there’s plenty to learn!




Earth Day

Books to Read – set up a FREE account on to read these online books for FREE for 14 days!


Plastic Bottle Irrigated Planter

Use a 2-liter plastic bottle to make a sub-irrigated planter – a great hands-on STEM activity for students to design and build!

Recommended for Grades 6-8.

Let us know if you need lesson plans or supplies to incorporate this activity in your classroom.

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