Guano Fertilizer: Features, Application And Disadvantages


Guano has long been known as a valuable fertilizer. The weathered bird excrement provides your plants with an ideal mix of nutrients. However, obtaining guano is not always environmentally friendly.

What is guano?

Guano is a fine-grained powder. It is formed when the droppings of seabirds weather on a soil rich in lime. This happens mainly at large breeding sites: The combination of a lot of bird droppings and lime-rich eggshells creates meter-high layers of guano.

The word “guano” originally comes from South America. In the language of the Incas, it means “dung”. The weathered bird droppings contain various phosphates, nitrates and organic compounds.

Guano fertilizer for your plants

Guano bietet deinen Pflanzen wertvolle Nährstoffe.

Guano Fertilizer: Features, Application And Disadvantages

Guano is a natural mix of valuable nutrients, bacteria, minerals and trace elements. Its high phosphorus and nitrogen content in combination with potassium and sulfur makes guano a particularly nutrient-rich plant fertilizer. It is suitable for vegetables and woody plants as well as for flowering balcony or tub plants.

Guano as a fertilizer offers many advantages:

Guano is an organic fertilizer. This means that the nutrients mentioned above are not present in their pure chemical form, but are incorporated into natural mixtures of substances. In the soil, the nutrients must first be made available to the plants. This task is performed by the numerous microorganisms in the soil. They decompose the guano fertilizer and, among other things, form valuable humus.
Guano therefore acts as a slow-release fertilizer. When it is decomposed by soil organisms, it gradually releases nutrients. This makes guano very productive.
Guano acts as a natural fungicide. It thus protects sensitive plants from fungal attack.
Guano fertilizer is often also enriched with rock flour and algae sediment – making it a valuable complete fertilizer.

Disadvantages of guano fertilizer

Für Guano werden Brutstätten von Seevögeln zerstört.

Guano fertilizer offers plants an ideal combination of nutrients – but its decomposition is not necessarily environmentally friendly.

Because guano is produced from bird droppings, it is particularly common on breeding grounds – especially on small islands along the coasts of South America. These islands are important refuges for many endangered seabirds and penguins. The extraction of guano harms these places: breeding sites and nesting burrows of penguins are destroyed for the fertilizer – they particularly like to nest in guano walls. This damages not only the affected populations, but the entire ecosystem. Homemade nettle manure is more environmentally friendly and also provides valuable nutrients to your plants.

Guano is also highly corrosive. The necessary protective measures for the heavy physical labor involved are rarely present in guano mining.

Properly fertilize with guano

Trag unbedingt Handschuhe, wenn du mit Guano-Dünger arbeitest.

If you want to fertilize your plants with guano, you have a wide choice: Guano fertilizer is available in liquid form and as powder, granules or fertilizer sticks:

Powder and granules are particularly suitable for plants in the garden or bed.
Liquid guano can be used to fertilize balcony and potted plants.
There are special guano sticks for indoor plants. Guano fertilizer in powder or granulate form smells pungent and is therefore unsuitable for closed rooms.

So you can use guano as a slow release fertilizer:

  • It is best to work guano fertilizer into the soil about ten to 20 centimeters deep before planting. Water the soil well afterwards.
  • You can also add guano directly into the planting hole. This way, the nutrients are exactly where the plant needs them.
  • Plants in the flowering or fruiting phase also need nutrients. You can fertilize them with guano in the irrigation water.
  • Guano releases its nutrients as needed by the soil quality. Therefore, overfertilization with guano is practically impossible.
  • As a short-term fertilizer in case of an acute nutrient deficiency, guano is not suitable due to its long-term effect.

Caution: Guano is highly corrosive. Wear gloves when fertilizing and make sure that no dust touches your eyes, respiratory tract or skin. Plant leaves will corrode on direct contact with undiluted guano fertilizer. Therefore, it is best to fertilize on a windless day and work the fertilizer directly into the soil.


  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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