12 Types of Earthworms (And How to Identify Them!)
Earthworms are a common sight to see after heavy rain. However, is it normal to find them in potting soil? How can you identify them when they all look so similar?
The 12 most common earthworms that can be found in lawns and outdoor gardens are:
- Dew worms
- Red wigglers
- Blue worms
- Pot worms
- Gray worms
- European nightcrawlers
- African nightcrawlers
- Red marshworms
- Dendrodes
- Crazy jumping worms
- Chestnut worms
- Green worms
There are thousands of earthworm species all over the globe! So which ones have you found? Let’s uncover the dirt on these interesting animals and dig a little deeper in the article below!
1. Dew Worm (Lumbricus Terrestris)
Dew worms live in the upper 2–3 inches of various soil types and can help increase soil porosity. However, due to their over-consumption of organic matter, this earthworm is considered invasive in North America.
Commonly Found in: Within topsoil
Color: Pink to reddish brown
Size: 5–10 inches (127–254 mm)
These large worm species can be up to 10 inches (25.4 cm) large and can be found in all soil types! You can easily identify them through their large size and their dark brown heads.
Dew worms typically live deep inside the soil creating vertical burrows but will surface to feed off of decaying matter. They can be helpful by aerating soils and preventing them from becoming too compact.
Unfortunately, this worm is considered invasive in North America and even in some parts of Europe.
Avoid moving these worms to the forest where they will pose a threat by consuming too much organic material. Limiting this abundance of organic layers can deprive other helpful lifeforms and bacteria of their homes and can easily increase the chances of water runoff.
2. Red Wigglers (Eisenia Fetida)
Yellow tails and thick clitella, or thickened rings of skin, are most commonly seen in red wigglers. This earthworm is frequently utilized for its prolific generation of worm casting, or worm manure, which can aid the growth of plants.
Commonly Found in: Below or alongside mulch
Color: Reddish brown
Size: 1–4 inches (25–355 mm)
Red wigglers are rarely ever found inside the soil and can be seen sporting yellow tails.
If you find thick, red worms at the top of your soil wiggling around decaying growth or compost, you probably have redworms!
These are some of the most commonly used earthworms because of their ability to rapidly consume organic waste and produce helpful worm castings.
>> Read more in our article about worm castings in potted plants.
These worms are not harmful and are commonly used in gardens all around the world.
3. Blue Worms (Perionyx excavatus)
Blue worms can be identified by their elongated bodies and less noticeable clitellum. They are regularly confused with red earthworms due to their similar appearances. As an epigeic or litter-dwelling earthworm, blue worms are likely to consume heavy quantities of mulch or low-growing crops.
Commonly Found in: Below or alongside mulch
Color: Brown with a blue sheen
Size: 1–3 inches (25–76 mm)
This worm is commonly used in composting and is frequently used to harvest worm castings. Unfortunately, these worms are also often sold to unknowing customers as red wigglers, so watch out!
Blue worms are thinner and more elongated than red worms. The clitella of blue worms are less prominent and are usually much more flush compared to red worms.
To quickly explain, the clitella are simply the thickened ring of skin containing the reproductive organs of earthworms and are some of the easiest ways to identify similar-looking earthworms.
These worms can produce prolific amounts of worm castings that your plants may benefit from. However, these worms are ravenous. They will need adequate amounts of food and may eat much of the useful mulch you leave on top of the soil.
Consider removing blue worms if you have any low-growing fruits and vegetables as it is very likely that they will eat these!
4. Pot Worms (Enchytraeidae)
Worms found in containers that are less than an inch long and are completely void of pigment are known as pot worms. These worms are frequently mistaken as juveniles of other earthworm species and can reproduce at alarming rates and compete with other beneficial soil-dwelling organisms.
Commonly Found in: Compost and potted plants
Color: White
Size: 0.03–1 inch (1–30 mm)
These confusing worms can be confused as juveniles of other earthworms, like red wigglers. Pot worms are also ridiculously small—typically only 1–30 mm long.
You can tell pot worms apart by their complete lack of pigment. The tricky thing, though, is that these clear worms can also be seen as fungus gnat larvae.
These worms are not necessarily bad and are excellent in providing plants with much-needed nutrition and minerals through worm casting.
Don’t worry though! They do not eat the roots of potted plants, which is something we will discuss more in-depth later on.
However, pot worms will compete with other earthworms due to their rapid reproduction speeds, especially in colder climates.
You can even find as many as 250,000 pot worms per square meter! Keep this in mind if you have other lifeforms in your soil that you’d like to protect.
5. Gray Worm (Aporrectodea calignosa)
In general, gray worms typically display 3 different shades of gray and pink throughout their body. These earthworms can help in aerating soils and reduce soil compaction.
Commonly Found in: Within topsoil
Color: Gray and pink
Size: 2 inches (50 mm)
The easiest way to identify these peculiar worms is through their 2–3 prominent shades of varying colors.
Some parts of their bodies can be dull and gray in hue, while other parts are tinged with pink.
Gray worms can help aerate and mix the topsoil as they burrow through them and release castings in the process. They can even survive droughts, which is perfect for our readers in hotter areas.
6. European Nightcrawler (Eisenia hortensis)
European nightcrawlers are commonly found on the soil surface and can easily be mistaken for red earthworms. However, these earthworms can grow up to 14 inches long and are oftentimes thicker than red wigglers.
Commonly Found in: Below or alongside mulch
Color: Dark red
Size: 7–14 inches (177–355 mm)
These worms look similar to red worms but are much larger and thicker in comparison.
They can also be found among leaf litter but are known to dig deeper at times in search of rotting leaves and grasses to consume.
European Nightcrawlers can live up to 6 years but may not be a great option for shallow containers or cramped garden beds. They need a generous amount of room to grow large and thrive, so keep this in mind.
7. African Nightcrawler (Eudrilus eugeniae)
Prominent clitella and bodies over 10 inches long are characteristics of African nightcrawler earthworms. These worms can be seen underneath mulch releasing worm castings high in nutrients.
Commonly Found in: Below or alongside mulch
Color: Purple-gray
Size: 6–12 inches (152–304 mm)
Although popular for vermicomposting, these worms can be difficult to tell apart from other earthworms.
But as always, we have some good tips you can utilize! African nightcrawlers have raised clitella, like a red wiggler, but are much larger and thicker in size.
They can even be over 10 inches (25.4 cm) long!
These helpful composters produce a prolific amount of castings that can help enrich the soil.
8. Red Marshworms (Lumbricus rubellus)
Unlike red wigglers, red marshworms are endogeic worms that live within the top 2–3 inches of soil. Additionally, the bodies of red marshworms are frequently much thinner and are deeper in brown hues compared to red wigglers.
Commonly Found in: Within topsoil
Color: Red and brown
Size: 1–4 inches (25–101 mm)
Red marshworms are commonly mistaken for red worms; however, they’re a different species. Compared to red wigglers, you can find red marshworms burrowing inside the upper 2 to 3 inches (7.62 cm) of soil.
If you look at them closely, you will also see that red marshworms have thinner bodies and are much deeper in color.
Because these worms help increase porosity in the soil, they can easily improve the soil’s overall water penetration and are great for no-till gardens.
9. Dendrodes (Dendrodrilus rubidus)
Typically found in Europe, dendrodes are litter-dwelling earthworms that live no deeper than 10 cm inside the soil. Dendrodes can be identified by their dark red bodies and orange tails.
Commonly Found in: Below or alongside mulch
Color: Dark red
Size: 1–3 inches (25–76 mm)
Dendrodes seem to be a common catch-all worm that some stores sell as red wigglers or pink worms. But, as always, this is its own species.
Normally, dendrodes can be found hiding underneath leaf litter no further than 10 cm deep into the soil. Oftentimes, these earthworms will have a yellow or orange tail and a dark red body.
These are especially common in Europe but can be found in North America.
10. Crazy Jumping Worms (Amynthas agrestis)
Crazy jumping worms are invasive earthworms that typically display wild, snake-like movements. Avoid moving these earthworms to new locations as they could disturb the ecological system in different areas.
Commonly Found in: Below or alongside mulch
Color: Gray or brown
Size: 1–8 inches (25–203 mm)
These “crazy” worms are invasive in the US due to their rapid ability to reproduce. Crazy jumping worms also tend to over-consume leaf litter, which can disturb the microbial and species diversity of the soil.
You can tell this worm apart by its thrashing s-patterned jumping and its glossy dark brown or gray pigment.
It is not recommended to use or move these worms to a new location due to their impact on the environment.
They will naturally disperse over time but be careful they do not spread to any other locations.
11. Chestnut Worms (Lumbricus castaneus)
Chestnut worms are small earthworms that can be seen among aged mulch and decaying leaves. Although they help produce worm casting, chestnut worms will be out-competed by other larger earthworms.
Commonly Found in: Below or alongside mulch
Color: Brown
Size: 1–2 inches (25–30 mm)
These little earthworms can be found right underneath dead leaves and mulch. For an easy way to identify this worm, check their clitellum to see if they are orange in appearance.
The Lumbricus castaneus, commonly known as the chestnut worm, is native to England.
Chestnut worm castings can be quite helpful for plants but the worms may be easily out-competed by other bigger worms.
12. Green Worms (Allolobophora chlorotica)
Green worms are endogeic, meaning they live in burrows in the upper 2-3 inches of soil. These earthworms are commonly identified by their pink or green pigment and can help aerate soils.
Commonly Found in: Within topsoil
Color: Green or pink
Size: 1–2 inches (25–30 mm)
You might think these are caterpillars but nope! This curious earthworm spends much of its life in the burrow systems underground and can hardly be found on the surface.
So if you’ve found these worms while tilling or digging through your soil, it’s very likely that you’ve discovered a green worm.
As their name suggests, these earthworms can either be found in their green form or in their pink form. They can also be found in the roots of aquatic plants and sometimes even on front lawns after rain, so make sure to keep an eye out!
How Are Earthworms Useful?
Despite popular belief, earthworms are not a threat and do not consume living plant tissue. The presence of earthworms can significantly improve and increase soil porosity and organic matter and improve general soil health.
Earthworms play a crucial part in our ecosystem. We directly benefit from the presence of earthworm populations!
By increasing porosity and incorporating additional nutrients into the soil, worms can greatly improve the overall health of the soil that our beloved plants live in.
Some people may claim earthworms are harmful and will eat the roots of plants, but these worms will only feed off of decaying matter. Earthworms will simply eat dead plants and will only consume them after they have rotted away.
Earthworms pose no threat to living plants and only feed on decaying matter.
FAQs
How long do earthworms live?
Earthworms can live for many years, depending on the species. The most common earthworm, the red wiggler, can live between one to five years. A nematode named Caenorhabditis elegans is a popular worm used in studies because of its 25 day lifespan.
What earthworms are rare?
The Oregon Giant Earthworm, Driloleirus macelfreshi, can grow up to 3 feet (0.91 m) long and burrow fifteen feet below the ground. However, this species is endangered and has been rarely seen. The last sighting took place in 2008.
Summary of Types of Earthworms
Earthworms can help gardeners create more healthy soils by creating burrows to increase aeration. They also consume dirt and decomposing materials to create nutritious worm casting that plants will benefit from.
The most common earthworms that can be beneficial in gardening include dew worms, red wigglers, blue worms, pot worms, gray worms, European nightcrawlers, African nightcrawlers, red marshworms, dendrodes, chestnut worms and green worms. Crazy jumping worms are invasive and can do more harm than good.
Sources
- “Earthworms” by Angela Gupta, Amy Rager and Megan M. Weber in University of Minnesota
- “Insects, mites, and nematodes” by John Obermeyer in University of Purdue
- “Jumping/Crazy/Snake Worms – Amynthas spp” by n/a in University of Massachusetts
