Research Team

Do earthworms really eat half their weight or even more each day?

July 27, 2023

In the world of vermiculture and vermicomposting, there's a popular claim that earthworms devour an impressive amount of food each day, often described as "earthworms eat half their weight in food every day," and at times, even exaggerated to consuming an equivalent or multiple times their weight in food. This notion has garnered attention and made people view earthworms as voracious creatures, swiftly converting organic waste such as kitchen scraps and animal manure into valuable compost. But, is there any truth to these claims? Let's dig deeper to understand the reality of earthworm feeding habits.

Unveiling the Reality

Upon closer inspection, we encounter significant issues with these assertions. Earthworms come in various species, each with distinct dietary preferences categorized broadly as herbivorous or detritivorous, depending on their diet of choice, be it plant debris or decaying organic matter in the soil. As a result, generalizing earthworm feeding habits with a single figure becomes impossible.

Even if we focus on specific composting earthworms cultivated for vermicomposting, variations in size, temperature preferences, and behavioral traits create complexities in establishing uniform feeding patterns or quantities.

The Diverse World of Organic Waste

Composting earthworms indeed thrive on organic waste, which includes an array of materials ranging from animal manure to sawdust from discarded mushroom bags, coffee grounds, fruit peels, and tea residues from kitchen scraps. Each type possesses unique characteristics, densities, and stages of decomposition, further adding to the intricacy of determining an exact proportion of body weight for their daily food intake.

The Ongoing Misconception

Despite the lack of concrete evidence, the widespread belief in earthworms consuming half their weight or more each day persists. An investigation into its origin reveals that both Chinese and English sources on the internet present similar statements, with claims fluctuating between earthworms eating half their weight to twice or even more on a daily basis. This misconception seems to be prevalent worldwide, simplifying a multifaceted reality into a single, misleading assertion.


While earthworms indeed play a crucial role in the composting process, we must approach their daily food intake with a more nuanced understanding. Their varied species, distinct diets, and diverse organic waste sources make it challenging to quantify their feeding habits precisely. Instead of relying on oversimplified claims, let's appreciate the complexities of earthworm behavior and continue to explore the fascinating world of vermiculture and vermicomposting with a critical eye.

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