TRUE Blog #16

What’s So Great About Seabird Guano?

November 29, 2021

What’s So Great About Seabird Guano?

With a balanced nutrient profile, time-tested ability to stimulate growth, and TRUE’s food-safe guarantee, Seabird Guano might just become your new favorite plant supplement.


We know what you’re wondering… and, yes: “guano” means droppings. Think of it as manure, but from birds and other flying animals (you may have heard about bat guano, too). Just like when we use the word “manure” to designate something more than bovine excrement, guano is a complex, nutrient-dense substance that is much more than “droppings.”

What Makes Seabird Guano Different? That Fish Diet!

Plants love guano. But don’t assume that every bird dropping is created equal.

Seabird guano is unique from other birds’ guano—and other types of animal manure—because it contains a specific mix of macro- and micronutrients that is incredibly supportive for both plants and soil.

Thanks to the birds’ fresh ocean buffet and the guano’s drying process, seabird guano is packed with Phosphorus, Potassium, Carbon, and Nitrogen. 

Plus, decomposed organic matter from the birds’ prey contributes even more helpful ingredients that soil microbes need to multiply and thrive.

Nutrient Makeup

Phosphorus (P) is especially important for root and bloom development, which results in more robust fruit and flower growth. On a microscopic level, strong root development means plants can absorb more water and nutrients from the soil—resulting not only in bountiful yields and big blossoms, but also long-lasting, happy plants. 

Potassium (K) supports root systems and photosynthesis. In other words, K is all about growth!

Carbon (C) and Nitrogen (N) are essential foods for all plants, as well as soil microorganisms. If you’re a home compost-maker, you’ll know that a balance of carbon-based and nitrogen-based ingredients are what make a healthy compost mix (along with some other important ingredients). Nitrogen is also responsible for supporting foliage growth.

An Amazing Soil Biostimulant

If you know TRUEⓇ, you know we’re obsessed with soil health. 

Supplying soil with macronutrients (carbon and nitrogen, specifically) and micronutrients (thanks to all those decomposed and decomposing fish parts) stimulates microbial activity. That ensures that the microscopic inhabitants within soil, like bacteria and fungi—and slightly bigger-than-micro lifeforms like earthworms—thrive.

Soil is amazingly alive! Read more about what makes up healthy soil, and how you can support it.

Nutrients For Now And Later

One of the uniquely wonderful aspects of seabird guano is its combination of readily available and slow-release nutrients.

What does that mean for farms and gardens? Plants get nutrition they need right away and they’re supported with other nutritional support throughout their whole crop cycle.


What’s It Good For? 

Seabird guano can be used on both indoor and outdoor plants, in-ground and in containers (but keep reading for a gentle word of advice regarding seabird guano and your houseplants). It’s pretty darn versatile!

The overall nutrient makeup of seabird guano encourages plants to grow rapidly and to develop robust flowers and foliage. Its high humus properties (high quantity of decomposed organic matter, a keystone of soil fertility) helps increase nutrient availability for your plants. 

Anything you’re growing with lots of leaves would benefit from some seabird guano. It’s a perfect plant food to help support for:

It’s known to improve yields, enhance flavor (especially of fruits and berries), and support the long-lasting health of perennials (thanks to the nutrients that support root systems).
Get to know more about our seabird guano, why we added it to the True OrganicⓇ plant food family, and how we ensure sustainability from our Founder and Chief Agronomist.

When To Apply

We recommend two applications per year, one in Spring and one in Fall for outdoor plants. Seabird guano helps fulfill plant nutrient cycle demands during seasons when flowering and root development could use some support.

Houseplants benefit from a Spring application, when they begin a new growing season, making lots of leaves and buds.

For some plants, seabird guano can be used throughout the flowering season to support robust blooms. This is especially great for plants with lots of foliage, like trees and berries. Always check with your local garden center, nursery, or farm and feed store to see what frequency is right for your plants.

Just like any plant food, it can be tempting to over-apply seabird guano in hopes that more is better. Always follow our mixing and application instructions on your TRUEⓇ product package! Adding too much or fertilizing too often can damage your plants. 


When To Be Careful

Seabird guano can be used for outdoor or indoor plants, but because of its potent smell, you might want to go light on application to indoor plants.

Outdoors, some wildlife may be attracted to the odor of seabird guano. Be careful if you live in a place with lots of wildlife, or protect your garden plot with a fence.


Sustainably Harvested

The best seabird guano comes from Peru—that’s where we ethically harvest our product for True OrganicⓇ Seabird Guano. 

While seabird guano exists in other places in the world, the deposits off Peru’s coast contain the absolutely highest quality guano for agriculture. Why? This part of Peru’s coast doesn't get much rain at all, so the guano is well preserved, high in nitrates and other macro- and micro-nutrients, and “cured” (dried) on the rocks for ideal consistency. 

These thick, dried guano deposits make it possible to harvest and make it very important to preserve the ecosystem that allows them to form—from the birds' nests to the dry climate.

Seabird guano has been used by humans as an agricultural supplement for hundreds of years. In the 19th Century, before commercial fertilizer was widely produced and used, seabird guano (and other natural ingredients like bone, manure, and ash) rose in popularity. In the 1830s, when Americans first sailed to the Chincha Islands off the coast of Peru to mine guano, the islands were coated with a 200-foot deep layer of seabird guano. In less than 50 years, the supply was nearly completely gone.

Thanks to environmental and economic efforts to preserve these “guano islands” and the birds that produce this incredible fertilizer, the deposits have begun to replenish and are now protected by law. 

Sustainably acquiring our ingredients for True OrganicⓇ products is non-negotiable. 

We collaborate with the laborers who harvest our guano, the Peruvian government, and environmental advisors who help protect the seabirds to ensure this valuable resource is available for many years to come. 

You can start to see why it’s so essential to ethically harvest and maintain sustainable commercial production of seabird guano products. Appreciating the reciprocal relationships between humans, wildlife, and ecosystems is what drives everything we do at TRUEⓇ. 

Food Safe 

As if all that wasn’t enough to illustrate just how wonderful seabird guano is for gardens, row crops, houseplants, orchards, and all manner of other green friends, our True OrganicⓇ Seabird Guano (just like every single TRUEⓇ product) is guaranteed food safe. True OrganicⓇ is the only plant food available that is made *ISO 22000 certified from Bureau Veritas* (a rigorous, world-class food safety management seal of approval).

Ready to give it a try? Find a bag of True OrganicⓇ Seabird Guano at your local gardening store with our convenient store locator.

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