BURY YOUR UNDIES.
DISCOVER YOUR SOIL.
The Soil Your Undies Challenge is a simple, hands-on way to see biological activity in your soil using nothing more than cotton underwear.
Healthy soil is alive. In fact, a single teaspoon of soil can contain billions of microorganisms working beneath our feet. These tiny organisms are the engine of the soil system — breaking down organic matter, cycling nutrients, building soil structure, and helping plants access the water and nutrients they need to grow. Active soil biology improves water infiltration, strengthens root systems, and makes soils more resilient to drought and stress. Simply put: without microbes, soil doesn’t function.
The Soil Your Undies Challenge is a simple, hands-on way to see this hidden life in action. The challenge works because 100% cotton is natural carbon — essentially food for soil microbes. When you bury a pair of cotton underwear in the soil and dig them up several weeks later, the microbes will have started to “eat” them.
What you find can tell you something about your soil. In soils with active biology, microbes will break down much of the cotton. In soils with less biological activity, the underwear may remain more intact. Results can vary depending on soil type, moisture, temperature, and microbial diversity — and that’s okay. Even partial decomposition is a sign that your soil community is hard at work.
It’s a fun, visual way to make the invisible visible — and to watch your soil come to life.
