What do Worms Eat
HOME · Sustainable Living

What do Worms Eat? Feeding Worms for Composts and Gardens

Below, we look at the importance of common squiggly worms in the ecosystem. Worms have become popular to keep or nurture for home gardeners or those seeking a more sustainable lifestyle. These little creatures can help you compost pretty much any food waste and increase the yield of your garden soil. To keep them happy, we first ask what do worms eat?

What to Feed Worms?

Worms feed on organic matter, primarily dead plant matter and microorganisms like bacteria and fungi. Worms out in nature can find food on their own - but what do worms eat when confined to a worm bin? You can feed compost worms with organic waste and food scraps.

However, keeping their food input's green and brown matter balanced is important. This will ensure the worms have a balanced diet of nutritious food since the green matter is rich in nitrogen, and brown matter is rich in carbon.


A Worm can eat eggshells, which provide calcium and grit to break down other foods. Eggshells are good for balancing pH levels.


Paper and cardboard sourced from household waste are also a rich carbon source for worm feed. Worms cannot digest inorganic substances.

The paper you might feed worms should not be coated with chemicals or plastic. The paper should be soaked in water and shredded before you add it to the compost.


Cotton is a natural plant fiber; worms can eat pieces of clothing made with cotton.

Fruit and vegetable waste

These make an excellent addition to a worm’s meal. Banana peels, apple cores, leaf and broccoli stalks, potato skins, pumpkins, squash, and fruit skins we throw away are things worms enjoy munching on. Worms eat food waste like moldy bread and cooked or soaked grains. The high sugar content of discarded waste, like melons, is some of the best worm food and will help worms gather around for a sound feast.

Coffee grounds

Worms eat coffee grounds and tea leaves. Not all tea bags are biodegradable, so you can just pour the contents into your worm bin and trash the bags with other plastic.

Animal Manures

Worms eat animal dung, too. They particularly relish cow manure and horse manure.


Worms like to eat dead leaves and other decaying parts of plants.

Large chunks of food take too long to break down into worm-sized bites. Therefore, break worm food down and spread it evenly on the soil surface. If you're super keen or working with larger discards, simply give them a whizz in the food processor.

What not to feed a worm

When you’re considering what a worm eats, there are certain foods that you should not feed them. You should avoid acidic, processed, and slow to biodegrade foods.

Acidic food

Oranges, lemons, limes, papayas, and pineapples have high acid levels and will burn the worm's skin.

Oily food

Worms breathe through their skin and, therefore, don’t feed worms oily foods that will coat the skin and make it hard for them to breathe. You can feed your worms pasta, but avoid doing so if covered in oil or grease (like from cheese). 

Salty and spicy food

Salt is an irritant that will cause a worm to dehydrate and die off. Therefore, you’re best not to feed worms spices like onions and garlic that are also acidic.


Grasses release heat and ammonia as they decompose, which endangers the lives of the worms.

Dry grains

Worms don't have teeth to chew on hard, dry grains, and the grains will give off too much heat.

Meat and Bones

Pests will invade the worm’s dwelling quickly if you add meat and bones to the food, and therefore, you’re best to avoid these when it comes time to feed worms.

Dairy foods

Dairy products produce a foul stench as they decompose; this pollutes the environment. Make sure you sort through any leftover food before feeding them to the earthworms; this way, you can avoid accidental poisoning.

All About Worms

Worms are everywhere. They exist inside living creatures, under the ground, and even in marine habitats. We have about 2,700 different kinds of worms; some are parasitic, while others are not. Parasitic worms live inside the body of other animals. The non-parasitic worms are known as free-living worms; they live underground or in marine habitats.

Worms have neither arms nor legs. They have just a tubular segmented body and no bones, either. They move around by wiggling their bodies to initiate a crawling motion.

Worms can crawl in forward and backward directions but crawl forward more often. The bristles or setae on their body help them crawl and anchor themselves firmly in their burrows. Worms vary in size, ranging from microscopic to two yards in length.

Worms have no teeth but strong mouth muscles that let them chew their food in bits. However, they’re still small creatures; therefore, they need small enough bits to intake when it comes to feeding worms.

Perhaps the most famous of free-living worms is the earthworm. They are classified under the phylum “Annelida.” Earthworms are a common sight where you have cool, moist soil. They are the most populous of soil invertebrates. 

Worms live in underground tunnels to protect themselves from the scorching sun. Earthworms have over 7,000 species, each with its preferred location to burrow in the soil. An earthworm has about 100 - 150 body segments, each providing important structural support.

Earthworms are chief agents of the decomposition of organic matter. Worms feed on bacteria, fungi, dead leaves, and tiny seeds, among other things. Earthworms recycle nutrients that plants find useful by going about everyday activities, eating, moving, and excreting.

Read more: Worm Facts.

Types of Earthworms

Photo by Karolina Grabowska from Pexels

Earthworms are hermaphrodites, and they have both female and male reproductive organs. Although a single worm has the organs to reproduce by itself, most earthworms need a mate to reproduce before baby worms hatch from eggs after around a 2 week gestation period. Earthworms do not have lungs but breathe through their skin by diffusion.

Below is a list of the most popular earthworms:

Red worms

These are popular bait worms. They are hardy and can tolerate a large concentration of decaying organic matter. Red worms mature within 179 days and produce at least 79 cocoons yearly. They grow to a length of 1 to 4 inches and live for about 700 days.


These grow best at a higher temperature than most earthworms. Under an ideal room temperature of 77 degrees Fahrenheit, a nightcrawler will mature in 350 days and produce 38 cocoons yearly. These worms can grow to a length of 8-10 inches.

Red wiggler

Also called the “brandling worm,” red wigglers are the most common composting worms. They find it easy to compost very large scraps of organic matter. If handled roughly, they can emit an unpleasant odor, and some people may be allergic to it. Red wigglers live close to the soil surface.

How Worms Affect Eco-diversity

Earthworms, although small, have the power to change soil and plant communities. Little wonder they are called "the ecosystem engineers." We classify earthworms as “Epigeic,” “Endogeic,” and “Anecic” based on the depth at which they live in the soil.

Epigeic worms live close to the soil surface and feed on decaying plants.

Endogeic worms live deeper in the soil in permanent burrows and feed mostly on soil and microbes. Anecic worms live near the subsurface of the soil.

Earthworms are known to survive best in aerobic systems. Most people agree that earthworms benefit the ecosystem, but a few researchers point out some negative effects.

Improved Soil Nutrients

How do earthworms enrich plant growth? Well, worms disintegrate plant residue and drag them deeper into the soil. Thus allowing the nutrients from these plant matter to get deeper into the soil. They feed on decaying plants and manure. Their digestive system mixes their food's mineral and organic substances to form highly concentrated castings.

Worm castings are rich in nutrients beneficial to plant growth. Earthworms generate tons of casts per hectare every year. And when worms die, their bodies decompose quickly, adding more nitrogen to the soil.

Better Soil Structure

The casts of earthworms glue soil particles together to form water-stable aggregates. They also enhance soil porosity and significantly improve soil drainage and water-holding capacity. Their upwards and downwards movement moves topsoil deeper into the ground and pushes up the soil in the lower strata to the surface. This mixes up the soil thoroughly.

Increased microbial activity

Earthworms consume microbes for food but release many more microbes in their feces or cast. Higher microbial activity is beneficial to plants.

Plant root growth

Tunnels dug by earthworms form a network of passages. That enables easier plant root penetration deeper into the soil. They line the tunnels with their cast, which is rich in nutrients. This allows plant roots to absorb nutrients with relative ease.


You can speed up decomposition by introducing earthworms to your compost bin when making compost. Red wigglers, Nightcrawlers, and red worms are common composting worms used in vermicomposting. For vermicomposting, you're best to introduce mature worms to the compost pile first.

Related read: How To Start A Worm Farm For Vermicomposting At Home.

Food source

Several animals find worms to be a delicious meal and source of nutrition. Birds, frogs, weasels, turtles, otters, and raccoons are some animals that eat worms. The eastern earthworm snake is a species of snake that feeds on worms.

Fishing bait

Recreational fishermen and small-scale fishing businesses rely heavily on worms to bait fish.

A report claims European earthworms cause declining species diversity in North American forests.

The researchers state that the worms disrupt the symbiotic relationship between soil fungi and roots. The report notes that worm activity in the area prepares the soil for non-native plants while endangering the survival of native plants.

Opportunities in earthworm farming

Worms in Soil
Photo by Sippakorn Yamkasikorn from Pexels

Raising worms commercially can be lucrative if you stay in a location where there are many fishing activities. Fishers buy earthworms to use as bait. According to the United States National Survey of Fishing, Hunting, and Wildlife-Associated Recreation, 30 million recreational anglers exist. And they exhaust over 40 billion USD annually in recreational fishing. Farmers and gardeners who use compost also buy earthworms for vermicomposting.

Once you have identified a demand for earthworms, all you need for worm farming is some earthworms, scrap food, and a worm bin, and you're ready to go. Worm farms do not require an enormous budget or space; you can start with a worm bin or two. Ensure the worms eat the right foods in the proper quantity, and you can harvest them soon enough.

Worms are best harvested from your worm farm in the morning before they move deeper into the soil for cooler temperatures. You can use a sorting screen to separate the worms from the soil safely without causing them injury.

Worm composting also provides a place for worms that may have been farmed. Other agricultural pursuits can benefit from adding worm compost to the soil to help its fertility and return.

What do worms need to survive?

In natural environments, worms fend for themselves without help. But on a worm farm, certain factors may make them less independent. An example of such a factor is the limited space of the worm bin. It makes it impossible for them to just migrate to another location when their burrows become uncomfortable.

Worms need more than food to survive in the worm bin. You must ensure PH levels, soil moisture, temperature, and other factors are favorable for survival.

Right temperature

Compost can get heated during biodegradation. Therefore, you need to regulate the temperature of the worm bin often. A temperature above 95 degrees Fahrenheit will boil the worms to death; at below freezing point, they will die.

PH level

Adding the wrong foods will put your worms in danger. Citrus fruit, papaya, tomatoes, and pineapples are acidic and do not have a chance of long-term survival in an acidic environment. A sign of unbalanced PH levels is a rotten smell; worm bins should be earthy. You can correct an imbalanced PH by adding neutrals like paper or eggshells. Furthermore, a balanced PH level helps keep your compost bin healthy and free from fruit fly larvae.

Diet ratio

As a general rule, worms should not be overfed or underfed. A worm will eat twice its body weight daily. Having less food will stunt its growth and performance. On the other hand, too many food scraps can cause excessive fermentation and protein poisoning, as the food will rot. The wrong foods can also be an open invitation to pests like earwigs, rodents, fruit flies, and centipedes.

Moisture level

Worms thrive in soil with water, but too much water slows down their oxygen intake. This forces them to come up for air. On the surface, worms become disoriented and have difficulty finding their way back into the soil. This endangers their life in many ways.

Soil renewal

The soil in a worm bin can not be fresh forever; after a while, it is full of worm casting, plant food, and microorganisms. Changing the soil can help ensure harmful microbes do not overpopulate the bin.


Worms are an important part of the ecosystem. They perform a vital role in recycling organic material. These slimy creatures enrich the soil with nutrient-rich worm castings, improve soil structure, and aid plant growth. They aid decomposition and prove very useful in compost making. They also serve as a food source for other animals, like birds and raccoons. Worms can also serve as a source of income for worm farmers and vermicompost producers.

So, what do worms eat? They will consume almost every kind of organic matter as long as it is not acidic or dry and hard.

Jen’s a passionate environmentalist and sustainability expert. With a science degree from Babcock University Jen loves applying her research skills to craft editorial that connects with our global changemaker and readership audiences centered around topics including zero waste, sustainability, climate change, and biodiversity.

Elsewhere Jen’s interests include the role that future technology and data have in helping us solve some of the planet’s biggest challenges.

Main Photo Credit schizoform on flickr (CC BY 2.0)
Pin Me:
Pin Image Portrait What Do Worms Eat?
Sign Up for Updates