Earth (Worm) Month: Let’s Celebrate These Wiggly Wonders!

Each April, people across the globe celebrate Earth Month. One creature that is crucial to this amazing planet does not get its due accolades. EARTHWORMS. They impact the soil, air and food you eat. And you have to admit, they are an intriguing invertebrate. At Organic Valley, we believe in the power of worms and hope you take the time to learn more about them during what we are endearingly calling Earth (Worm) Month.

Check out our activity page to find kid-friendly earth (worm) games and crafts!

You’ve dissected earthworms in science class, maybe slid them onto the end of a fishing hook or watched them slither across the sidewalk in the rain.

An earthworm was even the main character in the classic video game, Earthworm Jim. You might have used the buttons on the controller to help the earthworm dressed in a robot suit, slither, run and jump across the screen to battle the forces of evil. The same thing (minus the robot suit) happens in the soil.

Earthworms have been called “environmental helpers” for their important role in soil health. The slimy, wiggling creatures live beneath the surface, feeding on organic materials like decaying roots of corn, soybeans and other crops. Earthworm excrement, called castings, enhances soil quality. In fact, studies have found that earthworm populations have been used to determine soil health in field crops.

James J. Hoorman studied earthworms in his roles as an extension agent at Ohio State University and soil health expert for the Department of Agriculture Natural Resources Conservation Service. He calls them “soil engineers.”

“They improve the soil structure so much and make the soil so much better,” he said.

Beneath the surface of an Organic Valley pasture, earthworms tunnel through the soil, hard at work to improve soil health. This allows farmers to grow lush forage to feed the cows that produce the milk that goes into nutritious organic dairy products!

Let’s look at the benefits earthworms contribute to the planet and learn more about these fascinating invertebrates. Keep in mind, not all worms are created equal!

The Essential Role of Earthworms

Earthworms might be small, but the soil-dwelling invertebrates play a big role. Here are six benefits of having abundant earthworm populations in the soil.

Boost soil health: Beneath the soil, earthworms like the Canadian nightcrawler (Lumbricus terrestris) can burrow more than 1 meter deep and break up dense, compacted layers of soil that make it difficult for plants to grow.

Earthworms also build soil structure by consuming, processing and excreting carbon into the soil. The more wiggling worms tunneling through the soil, the better the soil density, soil fertility, water filtration rate and soil water content will be.

Create fertilizer: Worm castings are chock full of nutrients like iron, sulfur, calcium, nitrogen, phosphorus and potassium in higher ratios than bulk compost.

The microbiological colonies in the castings can repel insects and fight soil-borne plant diseases and are used in a 100% organic spray, called a tea, that improves nutrient absorption.

Improve global food production: Worm castings have been linked to fruit and vegetable yields that are 57% to 200% higher and improved taste and appearance. Additional studies show that earthworms contribute to 6.5% of global grain production and 2.3% of legume production, which means that boosting earthworm populations to improve soil health could help meet sustainable agriculture goals.

Recycle nutrients: Dead plants, fallen leaves, fungi and bacteria are among the tastiest items in a worm buffet. Earthworms can consume their own body weight in food on a daily basis and every bite is broken down and turned into castings that serve as nutrients and fertilizer in the soil.

Earthworms play a vital role in nutrient cycling, a process where energy and matter are transferred between living organisms, like earthworms, and nonliving organisms, like soil. On farms, improved nutrient cycling could reduce the inputs needed to produce crops.

Provide food for wildlife: Earthworms are a critical part of the food chain. Earthworms are considered a “superfood” for small carnivores because they are high in calcium and protein. Earthworms are also easier to catch than insects. This makes them an attractive food source — and it’s not just reptiles and early birds trying to catch the worm. 

Weasels, frogs and otters, along with pigs, raccoons and other omnivores are among small carnivores that devour earthworms.

Compost waste: Thanks to their voracious appetites, worms can help compost food waste. The process, called vermicomposting, involves setting up a worm bin and feeding red wiggler worms (also known as redworms) food scraps that are digested and turned into nutrient-rich soil.

“Worms break compost down very quickly,” Hoorman said. “(Worm castings) make really, really good food for the plants because the nutrients are so plant-available.”

Vermicomposting has the potential to reduce food waste while generating rich, dark compost that can be used as a soil amendment.

Jump to the end of the article to learn how to make your own worm bin.

Understanding Earthworms

The body of a common earthworm is made up of small ringlike segments called annuli that are covered in small bristles that earthworms use to move across the ground.

Earthworms have no lungs or eyes; the wriggling creatures breathe through their skin and use the receptors on their bodies to sense touch and light and depend on five “hearts” to pump blood throughout their bodies. Although earthworms can grow up to 14 inches long, most average 3 inches long; earthworms weigh just 0.39 ounces.

Earthworms are hermaphrodites, which means that each worm has male and female reproductive organs. To mate, two earthworms join and secrete a mucus; earthworms glide over the slime, picking up eggs and fertilizing them. The slime tube forms a cocoon that is deposited into the soil until the eggs hatch.

There are three types of earthworms:

• Epigeic earthworms are often bright red or reddish-brown and might have stripes. Red wigglers, the earthworms used in vermicomposting, fall into this category.
• Endogeic earthworms tend to be pale and can be gray, green, blue or pale pink.
• Anecic earthworms tend to be darker shades of red or brown around their heads with paler tails; nightcrawlers are anecic worms.

It's important to have all three types of earthworms in the soil, Hoorman said. “They all do different things. Anytime you have more diversity, it benefits the soil.”

Not All Earthworms Are Good

Earthworms can have major benefits for the ecosystem, but not all worms are created equal. There are more than 7,000 species of worms and some, like the invasive Asian jumping worm (Amynthas agrestis) do more harm than good.

Asian jumping worms were named for their thrashing movements, but it’s their appetites that make them dangerous. Like other earthworms, Asian jumping worms eat pieces of fallen leaves. However, they consume so much leaf litter that it affects entire ecosystems by changing soil structure, reducing soil moisture, exposing plant roots, speeding erosion and increasing soil pathogens. But the good news is, there are ways to mitigate this.

Thanks to rotational grazing and attention to soil fertility, pasture grasses on organic farms tend to have deeper roots. Since invasive jumping worms can decimate shallow-rooted plants, growing grasses with long roots can help adapt to pressure from these invasive species.

Ensuring soil health is fundamental to the success of organic farms, and our farmers are deeply committed to nurturing and maintaining it. Earthworms are essential for building soil density and fertility, improving water filtration and moisture retention and adding nutrient-rich castings to the soil. Improving soil health also means improving pasture quality and, with earthworms on the job, nature is doing a lot of the work. 

Earthworm FAQ

Do earthworms have eyes? Earthworms don’t have eyes but they do have receptor cells that allow them to tell light from dark, which enables them to determine whether they are under or above ground.

Why do earthworms come out when it rains? Scientists believe that it’s easier for earthworms to wriggle across the surface of the soil when it’s wet. Rain creates vibrations when it hits the ground, signaling to earthworms that it’s time to leave their burrows and set out on the soil surface to find food, a new habitat or to mate.

What do worms eat? Earthworms are hungry creatures. They are considered omnivores because their diets consist of leaf litter and other plant matter, manure and fungi.

Are worms insects? Although there are several insects with “worm” names — silkworm, tequila worm, glow worm — worms are not insects; they are invertebrates.

Do worms have brains? Worms do have brains. Their brains, while not complex, connect the nerves from the skin and muscles and control how worms feel and move.

Do earthworms feel pain? Yes. Researchers found that worms have receptors that detect pain or sensation and they use it to avoid or respond to hazards.

What are some things an earthworm learns? Earthworms might not have complex brains but they learn and adapt their behaviors to survive. For example, earthworms are sensitive to light and have learned to remain underground when it’s light and move to the surface when it’s dark.

How many hearts does a worm have? Earthworms have five hearts! Sort of. They have aortic arches that are heart-like structures that pump blood throughout their bodies.

What is the life span of a worm? The average life span for an earthworm is up to six years.

What are worm castings and how do they benefit the environment? Worm castings are another name for worm poop. As earthworms digest organic material, it’s encased in a coating and then excreted. The coating turns worm castings into a time-released soil amendment that releases nutrients over time.

Worm castings contain iron, sulfur, magnesium, copper, calcium and other micronutrients that make excellent soil additives, support plant growth, repel insects and fight soil-borne diseases.

How do earthworms reproduce? Earthworms are hermaphrodites. Though each worm has male and female reproductive organs, it takes two worms to mate. To reproduce, two earthworms join together and secrete a mucus. The worms glide over this, picking up eggs and fertilizing them before depositing the eggs in the soil to hatch.

Wow. That’s a lot to learn about earthworms and we hope it helps you understand why they deserve attention. They are an underground workforce that builds better soil and helps organic farms thrive.

During Earth (Worm) Month, take a moment to be inspired by these wiggly wonders. Our planet depends on them!

Want to take matters into your own hands? Here are tips for vermicomposting.

Making a Simple Worm Bin

1. Get a bin that measures around 18 inches wide, 24 inches long and 18 inches deep. It should have a tight-fitting lid. Thick Styrofoam boxes or plastic storage containers with multiple holes poked into them work well; you can also purchase commercial worm bins.

2. Fill half the bin with shredded newspaper and a handful of garden soil.

3. Add worms. Red wiggler worms are well-suited to vermicomposting because they eat large amounts of food, reproduce quickly and like communal living. In contrast, other species of earthworms like nightcrawlers, can’t process large amounts of food waste and don’t like confined spaces.

4. Place the bin in a cool, dark location like a basement or under the kitchen sink. Worm bins shouldn’t be placed outside because of the temperature fluctuations.

5. Every one to two weeks, open the bin and add fruit and vegetable scraps to feed the worms. Never put meat, dairy, fatty or oily products in the worm bin because it will create harmful bacteria and odors.

6. Collect the castings and add them to the garden.