Guinea Pig Waste: A Sustainable Fertilizer Solution?

Have you heard the saying that one man’s waste is another man’s treasure? How about, “One guinea pig’s waste is a gardener’s composting treasure?” You probably haven’t heard the second version because I just made that up. However, the truth is you can use your piggy’s poop and pee to make plant fertilizer in a few easy steps.

When composted, guinea pig poop and urine-saturated hay make an excellent fertilizer for the garden. Since cavies are omnivores, their excrement contains essential micronutrients for plant growth. However, it is crucial to compost the waste before using it on plants to destroy potential pathogens.

Composting is a natural process of converting organic waste into plant and soil food. So, instead of filling up your trash can with stinky hay and dung, you can put it to good use instead. That way, you can grow healthy plants, do your bit to save the environment, and save yourself some money too. Let’s find out how you can turn your piggy’s little turds into treasure next.

How To Use Guinea Pig Poop As Fertilizer

While it is possible to use guinea pig poop as fertilizer for plants, it certainly helps to understand composting and how to make it.

Understanding Composting

Composting is a process where organic materials, like kitchen scraps, yard waste, and animal manure, are converted into nutrient-rich soil. The composting process is carried out by a community of microorganisms – including bacteria, fungi, and earthworms – that work together to decompose the organic matter.

Composting Guinea Pig Poop

Before using cavy poop as a fertilizer, it is essential to compost it first. This is because fresh guinea pig poop may contain harmful pathogens that should not be directly applied to plants. The composting process not only helps to break down the waste but also raises the temperature inside the compost pile, which kills potentially harmful bacteria.

To make compost from piggy poop, you should combine the poop with other organic materials like straw, leaves, or kitchen scraps. Ideally, the compostable mixture should consist of a balance of nitrogen-rich “green” materials (e.g., cavy poop, kitchen scraps) and carbon-rich “brown” materials (e.g., straw, leaves).

The combination of green and brown materials ensures a proper carbon-to-nitrogen ratio, contributing to the decomposition process.

Creating the Compost Pile

Choose an area in your garden that receives partial sunlight and has good drainage. In this area, you can either create a compost pile on the ground or in a compost bin to contain the mixture. Avoid areas prone to flooding or where water can accumulate, as excessive moisture can disrupt the composting process.

Aeration and Turning

To facilitate decomposition, you must turn the pile regularly with a pitchfork or shovel. Doing this helps to aerate the compost and provides oxygen to the microorganisms, which speeds up the decomposition process.

A well-maintained compost pile can produce usable compost within a few weeks to several months, depending on factors such as the composting method and environmental conditions.

Nutrient Content of Guinea Pig Poop

Now you know the basic process of composting, let’s look at the nutrient content of guinea pig poop to see how it can nourish your plants as a biofertilizer:

NPK Ratio

Given their herbivorous diet, cavy poop is a valuable source of essential nutrients for plant growth. The primary nutrients found in your piggy’s poop are nitrogen (N), phosphorus (P), and potassium (K), commonly referred to as NPK.

The exact NPK ratio of cavy poop can vary depending on their diet and the bedding material used. However, on average, guinea pig poop has an NPK ratio of approximately 1-1-0.5, which makes it relatively higher in nitrogen compared to phosphorus and potassium.

These nutrients are fundamental for plant development for the following reasons:

  • Nitrogen supports leaf growth,
  • Phosphorus aids in flower and root development, and
  • Potassium enhances overall plant health and resistance to diseases.


In addition to the NPK nutrients, guinea pig poop also contains essential micronutrients and trace elements. These are crucial for various biochemical processes in plants and their overall health and vitality.

The micronutrients in guinea pig poop include the following:

  • Calcium,
  • Magnesium,
  • Sulfur,
  • Iron,
  • Manganese, and
  • Zinc.

4 Benefits of Using Guinea Pig Poop as Fertilizer

Let’s look at some of the other benefits of using cavy poop as a fertilizer next:

1. Environmentally Friendly

Using guinea pig poop as fertilizer contributes to environmental sustainability. But how? By composting and recycling organic waste, gardeners can divert waste from landfills. This helps reduce the burden on waste management systems and minimizes greenhouse gas emissions associated with organic waste decomposition.

2. Cost-Effective

Cavy poop is a cost-effective alternative to commercial fertilizers because the materials needed for composting are readily available. Additionally, by producing compost on-site, eco-friendly gardeners can save money on purchasing synthetic fertilizing products and improve soil health in a more budget-friendly manner.

3. Soil Enrichment and Fertility

Compost made from guinea pig poop enhances soil structure and fertility. This is because the organic matter in compost improves soil aeration, water retention, and nutrient-holding capacity. Additionally, the gradual release of nutrients from compost sustains plant growth over an extended period, reducing the risk of nutrient leaching and runoff.

4. Improves Plant Health and Resilience

The balanced nutrient content in guinea pig poop compost supports healthy plant growth and strengthens plants’ natural defenses against pests and diseases. As a result, plants grown with compost tend to be more resilient and less susceptible to environmental stressors.

Precautions and Considerations

As excited as you might be to start your new side hustle producing eco-friendly fertilizer, there are three precautions to consider.

Composting and Aging

Proper composting takes time, which is crucial to ensure that guinea pig poop is safe for use as fertilizer. This is because fresh poop should never be applied directly to plants, as it may contain harmful pathogens. Therefore, composting and aging allows the compost to reach temperatures that eliminate potential pathogens, making it safe for use.

Dilution and Mixing

Guinea pig poop compost can be pretty potent due to its high nitrogen content (potent poop!). Therefore, it is essential to dilute the compost with regular garden soil or other compost before using it on plants. This prevents over-fertilization, which can be detrimental to plant health.

Soil Testing

Before applying guinea pig poop compost to specific plants, conduct a soil test to assess the nutrient levels in the soil. Soil testing helps determine the appropriate amount of compost, ensuring that the plants receive the correct nutrient balance for optimal growth. Additionally, it helps to monitor the pH most suitable for the plants in question.


Guinea pig poop can be effectively utilized as a natural fertilizer for gardens and potted plants as long as it is composted. By composting guinea pig waste and following proper precautions, eco-friendly gardeners can turn this organic material into nutrient-rich compost. Doing this can enhance soil fertility, support plant growth, and contribute to sustainable gardening practices.