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Complete Guide to the Best Worms for Vegetable Garden Success [and MAGIC Soil!]

In our collective gardening imagination, earthworms are synonymous with healthy soil – and with a good reason.

Is the magic of earthworms just a myth or is there a seed of truth to it?

It turns out that there is a lot more than just a seed. There is a good reason why we celebrate earthworms as the ultimate natural soil menders.

However, you may have heard that there are various species of garden worms and earthworms. What’s the difference between them? Is each species specialized for a specific purpose? What are the best worms for vegetable garden soil?

Let’s discover the secret of garden worms and all their roles in the garden. 

Dig in!

When We Say “Worm,” What Do We Mean?

earth worms decomposing vermicompost organic fertilizer
We’ve lost count of all the worm species we’ve seen over the years. Some worms are invasive garden pests – such as jumping worms and cutworms. But not all worms are terrible! Let’s talk about some of our favorite garden-friendly earthworms like red wiggler worms and nightcrawlers.

For simplicity of this article, when I say worms, I’m considering only the annelids, segmented worms, specifically the ones belonging to the family Lumbricidae.

Other worms like the nematodes also interact with your garden and plants, but they are a whole different story.

What is also important to note is that annelid worms can’t cause damage in your garden – unlike some members of the much more versatile and diverse nematodes.

Why Are Worms So Good for Your Vegetable Garden?

Earthworms in the garden are like secret, spec-ops soil specialists. Most of the time you won’t even know they are there, but down below the ground, they are working hard on fertilizing and aerating your soil

The presence of earthworms in your soil indicates that it probably has enough organic matter to sustain the worms – and your plants.

Moreover, these tiny digesters will ensure that all organic matter entering the soil system will get degraded by the worm’s feeding activity.

That’s right – the most beneficial activity earthworms perform in your garden is creating nutritious substrate from organic matter by digesting it and enriching it in their guts. 

Wait a minute,” I hear you say, “So the earthworm poop is the best thing about them?!

The short answer would be “Yes” – just ask your plants!

The long answer would be that by (pre)digesting the organic matter, worms make all the nutrients highly available to the plants. 

As the University of Arizona Cooperative Extension explains it, the earthworm’s gizzard grinds the consumed food plus soil together.

As the mixture passes through the worm’s little guts, it is supplemented with very rich intestinal fluid that contains sugars, amino acids, and other organic matter.

The worms then excrete the full mixture in the form of the worm castings. The castings blend with the soil, thus increasing its fertility.

The worm castings are essentially what vermicompost is made of, but more on creating the “black gold” a bit later.

Another perk of having earthworms in your garden soil is that they actively aerate the soil by digging tunnels, helping the needed oxygen and water penetrate into the root zone.

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Composting – Earthworms vs Red Wigglers

You’ve probably heard of vermicompost – the “super-compost” made with the help of worms. 

The process of vermicomposting is quite different from traditional composting.

With classical, microorganism-led composting, the process is slower as you have to wait for the bacteria to do the job at their microscopic pace.

However, by adding worms to the compost, they will actively eat the macroscopic scraps and waste material you provide for them, producing enriched worm castings in the end.

Additionally, they will redistribute this material and dig through the pile or the bin – so you don’t have to. There is no need to turn or manipulate the vermicompost pile. 

The University of Hawai’i at Manoa has done some extensive research on the quality and efficiency of vermicompost.

They found that vermicompost helps increase yields, even when compared to the standard compost, while also suppressing diseases and pests.

They also discovered that vermicompost contains all the essential nutrients – nitrogen, phosphorus, potassium, calcium, magnesium, and micronutrients.

The best thing is that all of these goodies are highly plant-available!

Vermicomposting has a simple basic principle – you create a worm-friendly setup, add worms and organic waste that will be their food. 

However, you may be under the impression that vermicomposting is tricky because you need a special kind of worms, not just regular earthworms you can dig out from your garden soil. 

All of the extra hustle makes the idea of worm composting a bit less appealing when compared to the traditional, easy-going composting, right?

However, it is not as bad as you may think – the setup can be straightforward, and the worm species you need to make a quality vermicomposting setup are easy to get a hold of.

What Are the Best Worms for Vegetable Garden Soil?

vermiculture red wigglers and earthworms
The adaptability of red wigglers (Eisenia foetida) allows them to survive compost and worm bins. Nightcrawlers (Lumbricus terrestris) are also excellent for garden soil. However, nightcrawlers don’t thrive in compost bins like red wigglers. Instead – nightcrawlers prefer burrowing deeply underneath natural garden soil.

There is more than one species of earthworms, and some of them behave differently than others. We call the different lifestyles, roles, and habitat preferences of each species their ecological niche.

When you dig into the soil, you will most readily find the common earthworms or nightcrawlers, with Lumbricus terrestris being the best-known species.

Common names of the species fit perfectly – these creatures live below ground, deeper in the soil, and crawl out to the surface only during humid nights or during very cloudy rainy days.

They perform all the beneficial roles in the garden soil I previously described.

However, composting is a whole other story.

Compost bins are rarely really deep, and organic matter is added on the top. That is incompatible with the nightcrawler’s lifestyle and feeding habits.

Also, compost bins and piles usually get quite warm, and earthworms are definitely not fans of heat. If they can’t escape by burrowing deep into the soil, they will most likely die.

Luckily for all the vermicompost enthusiasts, there are alternatives.

Let me introduce you to red wiggler worms.

Read More – How to Keep Garden Worms Alive and Well! Red Wiggler and Earthworm Guide!

Are Red Wigglers the Same as Earthworms?

Red wiggler worms (Eisenia foetida and Eisenia andrei) and earthworms are cousins from the same family, but they’re not the same species – not even in the same genus.

What is more, their ecological niches differ. 

Unlike earthworms, wigglers are surface-dwelling and don’t burrow deep into the soil (but they do require some cover). Instead, they live and feed at or near the surface.

Also, red wigglers are smaller, have higher population densities, and can withstand higher temperatures. All of these traits make them ideal for quick and easy degradation of the plant waste in your compost system

Interestingly, red wigglers are renowned for their ability to break down cattle manure. Days-old manure is one of the places where you can regularly encounter them.

Are Red Wiggler Worms Invasive?

Most earthworm and red wiggler worm species have spread around the world along with the European settlers. However, there is a difference in their impact on the environment.

The typical red wigglers, E. foetida and E. andrei, are thought not to cause any environmental issues.

However, Lumbricus rubellus is also found in the market under the name Red worm. These large worms burrow near the soil surface and consume organic matter above. They are also popular fishing worms due to their size and liveliness.

However, there is a concern that, as a non-native species, this worm causes damage to the North American forests.

Although it can give good composting results, especially in combination with red wiggler worms, it’s best to abstain from using L. rubellus if you’re not in Europe.

Can You Put Red Wigglers In Your Garden?

Unlike the earthworms sitting there below your feet, you will likely have to introduce the red wigglers from outside sources. 

Simply releasing redworms into your garden is not the best option. These active critters can move away from you.

Besides, if you live outside of Europe, there’s an ethical question of releasing a non-native species freely into the environment, even if it is considered harmless.

For optimal results, keep your red wigglers contained.

You can set them up in a raised bed with a hefty amount of mulch, keep them in the vermicompost bin, or use them on a manure pile if you have one.

Where Can You Find Red Wiggler Worms?

You can purchase the red wigglers online or from your local worm farm, bait shop, or garden center.

If you feel adventurous, you can seek them out in moist leaf litter and cow manure – although they are initially from Europe, red wigglers are now naturalized on all continents except Antarctica.

Add this nifty refrigerator magnet for a handy reference as to what red wigglers like to eat:

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Can Earthworms and Red Worms Live Together?

Earthworms and red wigglers have completely different lifestyles, so they won’t compete for resources.

However, the fact that they differ so much means that not every situation is suitable for both species. 

If you release red wigglers in your bare garden or bed, they will probably escape, die, or get eaten by birds as they don’t burrow. 

Likewise, as mentioned before, earthworms are not suitable for compost bins as they are not gregarious, like cooler temperatures, need to burrow deep, and are slower in processing larger amounts of organic waste.

They would need a large compost bin to thrive.

However, there are setups where there can be an overlap between the needs of both species. 

Outdoor open-bottom compost bins and compost piles can host both earthworms and red wigglers.

The wigglers will feed on the top of the pile and do most of the hard decomposing.

The earthworms will create their base in the soil below the compost pile and venture into it from below, aerating the bottom part of the pile and additionally helping process the waste.

Read More – Worm Composting in Garden Towers – Expert Tips and Guide!

Vegetable Garden Worms FAQ

Most homesteaders don’t realize that choosing the best worms for your garden takes a lot of work – and consideration.

You may also encounter questions in your worm selection process.

That’s why we put together this list of helpful garden worm FAQs and answers.

We hope they help you!

Read More – 6 Best Worm Farm Kits and Soil Composters for Lush Garden Compost!

Worms Are Amazing for Vegetable Garden Soil

Annelid worms are garden soil magicians.

They turn organic waste into a rich soil-nutrient mixture simply by digesting it and exerting it in the form of worm castings.

However, not all species of worms work for all occasions.

Earthworms, as their name suggests, prefer to dig deep into the soil, work slowly and solitarily. They are efficient in large numbers, but those numbers require lots of space.

At the same time, red wiggler worms are specialized for ground-level work, successfully handling surface plant waste, leaf litter, and cow manure, and are very efficient due to their large colonies and speed.

If you want to try out vermicomposting or degrade the mulch in your garden and get some worm castings out of it, you can buy red wigglers and witness the magic yourself.

On the other hand, keeping the soil healthy, moist, and rich with organic matter and plant life will naturally encourage earthworms to thrive and do their job quietly but diligently.

Is there anything else you’d like to know about earthworms and red wigglers? Let us know in the comments!

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Author

  • An environmental analyst, gardener, insect enthusiast, and a mom of three, trying to pour her life-long naturalist experience into useful articles. She is passionate about protecting biodiversity, achieving harmony with natural ecosystems, and raising kids conscious of - and conscientious about - our shared environment.

Kathy

Wednesday 14th of September 2022

Thank you for this article!! It's been the most informative so far.

I bought compost earthworms for a science project to see how worms mix soil in a jar. They asked us to add dark soil, sand, dark soil, then oats. I added the worms I bought online. There is a fine webbing on the top in all three jars. Do you know what this is?

I also added the extra worms to my in-laws raised herb garden and around one small tree before I knew the difference in worms. Do you think there will be harm?

Also, I live in very south Texas- McAllen. No forests. :)

Elle

Wednesday 21st of September 2022

Hi Kathy! First of all, I’m extremely glad that you’ve found the article helpful - that was the point of creating it! So thank you for the precious feedback.

Now, about your science project. It is difficult to tell with 100% accuracy without a picture, but my guess is that the webbing that appeared on all the jars simultaneously is some type of mold. From your description, the top layer is oats - notoriously prone to going moldy if damp and stagnant. I suppose that it drew on the moisture from the dark soil below.

I don’t know if there was a lid on the jar or not, but if the lid was on, definitely too much moisture was stuck in there and led to the formation of delicate mold filaments on the top.

On the other hand, if the oats are fully dry, we could be talking about flour or meal moth infestation. However, in the case of moths, the webbing is not so noticeable - there would be clumps of oats connected with the silky thread, and the tiny moth larvae would be somewhere in the middle of it.

I have to say that it would be better if the project would be designed in a more earthworm-friendly manner. A jar (unless a very large one) is unlikely to provide them with sufficient space to move around and do their worm magic. A broader, transparent bucket or a food container would be a better choice. That is especially true for red wiggles (which is what you usually get when you buy “compost earthworms”) as they dwell near the top of the substrate instead of burrowing deep.

Also, when adding oats, use only a very thin layer to avoid mold and let the worms process it efficiently. You can always add more later if needed.

Finally, if moisture is an issue and you keep getting mold, don’t cover the vessel with a lid. Instead, put a breathable cover on the top of your mix - such as an old newspaper or paper towel. Wigglers love to snuggle right under such cover - as they would do under a layer of dry leaves in nature (that’s also an option if the project allows leaves as an additional element). In the case of very hot and dry weather, you can also add a lid on the top.

The earthworms won’t do any harm to your in-laws' garden, regardless if they’re wigglers or regular earthworms. They all feed on the decaying matter and don’t damage the plants. Since it’s quite dry where you are, the earthworms will probably burrow and try to survive in the deeper layers of the soil, while wigglers will, well - wiggle away, to find a cover that’s moist enough to serve as their home.

Good luck with the project!

Katarina

Elle

Wednesday 14th of September 2022

Hi there Kathy! Thanks for stopping by and I'm glad you enjoyed the article! I've sent your query to Katarina, she's our environmental analyst and insect enthusiast - she loves responding in detail to questions like yours so keep an eye out! I'll post her response here the minute I get it :) Have a great day! Elle