Bat Poop and Compost

Bat guano, the nutrient-rich waste (AKA bat poop) produced by insect- and fruit-eating bats, has long been recognized for its exceptional ability to enhance soil fertility, increase crop yields, and accelerate compost breakdown. Used properly, it can be a game-changer for gardeners and educators interested in sustainability and regenerative agriculture.

Bat guano was once so prized that it became the foundation of entire national economies. In the mid-19th century, Peru exported millions of tons of guano, primarily from islands off its coast, to Europe and the United States, where it was used to restore depleted agricultural soils. The “Guano Age,” as historians refer to it, helped catalyze the industrialization of farming. In 1856, the U.S. even passed the Guano Islands Act, which allowed American citizens to claim uninhabited islands with guano deposits from birds and bats on behalf of the United States. Control over these islands, and the lucrative fertilizer they contained, led to international conflicts and colonial expansion. This period marks one of the earliest large-scale examples of global agricultural input trade and highlights just how essential natural fertilizers like guano were to feeding growing populations before synthetic alternatives existed.

But before you grab a shovel and head for a cave: stop. Improper handling of guano can be harmful to your health, damage fragile ecosystems, and violate local wildlife protection laws. Here's what you need to know before you add guano to your garden.

What Makes Bat Guano Effective?

From a soil science perspective, bat guano is rich in:

• Macronutrients (NPK): High concentrations of nitrogen (N), phosphorus (P), and potassium (K) promote leafy growth, strong roots, and flower/fruit production.

• Beneficial Microorganisms: Supports microbial activity and biodiversity in compost and soil.

• Carbon and Trace Minerals: Improves soil structure, moisture retention, and nutrient cycling.

This combination makes it ideal for regenerating depleted soils and fast-tracking compost piles, particularly in nature-based solutions that prioritize soil health, ecosystem services, and climate resilience.

Nature-Based Solutions and Guano’s Role

In climate adaptation and environmental restoration, nature-based solutions focus on using ecological processes to solve human problems like soil erosion, degraded farmland, or food insecurity. Bat guano fits perfectly in this model because it:

• Rebuilds organic matter in soil without synthetic inputs

• Enhances carbon sequestration through healthy microbial activity

• Increases water retention and biodiversity in growing systems

• Supports pollinator-friendly and pesticide-free agriculture

In short: it’s compostable, regenerative, and works with (not against) nature.

How to Use Bat Guano in Your Garden or School Compost Program

Here’s a safe and effective way to use bat guano in home or educational composting:

DO:

✅ Purchase from a certified, ethically-sourced supplier (check for OMRI-listed or USDA Organic labeling)

✅ Use gloves and wear a mask when handling dry guano, as it can become airborne

✅ Mix small amounts into compost piles (1–2 tablespoons per cubic foot of material)

✅ Keep it in a dry, sealed container away from children and pets

✅ Use in moderation as high-nitrogen guano can burn plants if over-applied

DO NOT:

❌ Do not harvest guano from caves or roosts. This is dangerous, often illegal, and harms bat populations

❌ Do not apply guano directly to seedlings or plant roots without composting or diluting

❌ Do not store near food or in enclosed living areas

❌ Do not use without proper ventilation

A Note on Safety and Responsibility

Let’s Go Compost provides this information for educational purposes only. We do not endorse or assume liability for individual use, application methods, or sourcing of bat guano. Always consult a certified agricultural extension agent, composting professional, or environmental health expert before introducing any high-nitrogen inputs into your compost system, especially in school garden, home garden, or community garden settings. Improper handling of bat guano can expose users to histoplasmosis, a respiratory illness caused by airborne spores. For safety, always buy guano through professional suppliers and never attempt DIY harvesting.

A Little Guano Goes a Long Way

Bat guano is one of the most powerful natural fertilizers on Earth. When used properly in compost or garden beds, it strengthens soil structure, feeds plants, and supports regenerative ecosystems. Its role in nature-based solutions highlights its ability to combat environmental degradation using what nature already provides.

But like all things in nature, respect is key. Use guano safely. Source it responsibly. Teach it accurately. And, as always, prioritize safety and sustainable sourcing.