September 15, 2023
A Hidden Treasure: The Value of Frass in Agriculture and Ecology

The waste produced by insects holds immense value, enriching soil fertility, promoting plant growth, and contributing to sustainable practices.


It may not be the most glamorous topic in agriculture or ecology, but the waste produced from insect farming holds immense value for improving the health of soil and growth of plants while reducing the environmental impacts of agriculture.

Whether its enhancing soil health and fertility, promoting plant growth or in pest management efforts, let’s delve into the world of frass to uncover its hidden potential and its importance in sustainable agriculture and ecology.

What is Frass?

Frass is the term used for insect manure. However, this material, produced by various insect species as a by-product of their feeding activities is more than simply manure, consisting of insect’s excrement and their shed skin, as well as partially decomposed substrate. Frass can vary in composition depending on the insect species and their diet, but it is typically rich in organic matter and nutrients. The frass most commonly available to farmers and gardeners come from mealworms, crickets and black soldier fly. Arguably the most valuable form of frass comes from black soldier fly production due to the manner in which it is produced and the diversity of inputs used to produce it.

The Nutritional Value of Frass

Frass is a natural fertilizer that provides a viable and sustainable alternative to synthetic fertilisers.

Frass is high in nitrogen, phosphorus, and potassium, making it an effective fertilizer for a variety of crops. It also contains a diverse range of micronutrients, such as calcium, magnesium, and iron, which are important for plant growth and health. These nutrients are available in forms which are readily available for plant uptake.

Frass also contains plenty of beneficial microorganisms such as bacteria and fungi. These microorganisms contribute to soil health, promote nutrient cycling, and enhance plant immunity. As natural soil probiotics, the microbes found in frass make nutrients more accessible to plants and make plants stronger.

Enhancing Soil Fertility

One of the primary benefits of using frass in agriculture is its ability to improve soil fertility. When frass is incorporated into soil, it immediately enriches the soil with nutrients, increasing its overall nutrient content. Frass is a sustained release fertiliser however, continuing to release nutrients into soil over time and making it accessible to plants, providing long-term benefit.

Farmers who incorporate frass into their fertiliser regime report improved crop yields and healthier plants. Additionally, the organic matter in frass further helps improve soil structure, water retention, and microbial activity, all of which are vital for soil health.

Promoting Plant Growth

Frass doesn’t just benefit the soil; it directly benefits plants as well. The nutrients present in frass are readily absorbed by plants, leading to increased growth rates and overall health. Studies have shown that using insect frass as a fertilizer can result in larger and more vigorous plants. Microorganisms found in some kinds of frass have been shown capable of nitrogen fixation, the solubilisation of potassium and phosphate. Some of these microorganisms also excrete plant growth promoters, stimulating plant growth even further. Frass is therefore particularly valuable for farmers looking to maximize their crop yields and build their soil health while reducing the need for synthetic fertilizers.

Pest Management and Plant Protection

Frass also plays a role in reducing pest and disease pressure as it naturally contains a host of different biomolecules that enhance plant immunity. Principle of these molecules is chitin, which is a tough polymer that make up insect shells. When insects grow, they shed their skins. These shed skins are found in large quantities in frass, and the chitin from these shells promotes the soil microbiome and stimulates plant immune responses. Chitin has been found to be especially good at supressing fungal pathogens and warding off nematodes.

Sustainability and Frass Utilization

Using frass as a fertiliser in fields or gardens aligns with the principles of sustainable agriculture and a circular economy. Through recirculating organic matter through insects, turning it into frass and then using that frass to grow our crops, we reduce the environmental footprint associated with chemical fertilizers and promote natural systems of nutrient cycling at the same time. This conserves resources while fostering a more balanced and resilient ecosystem.
Frass holds significant value in agriculture. Its nutrient-rich composition can enhance soil fertility, promote plant growth, and contribute to natural pest management strategies. Using frass in combination with other sustainable agricultural practices can lead to healthier soils, increased crop yields, and reduced reliance on synthetic chemicals.

Frass is a hidden treasure waiting to be discovered by every avid gardener and responsible farmer keen on creating the best conditions for their plants now, and ensuring their soils stay productive in future.

Frass is available to purchase on our online shop