Red Wiggler Composting Worms: Everything You Need to Know

This guide will introduce you to the red wiggler to include a deeper on dive on the species and information on breeding, life cycle, and reproduction. We’ll talk about how to maintain red wigglers and why they should be the go-to worm for most composters.

Introduction to the Red Wiggler: Anatomy, Reproduction, and Life Cycle

Red wiggler picture taken at Urban Worm Company's HQ

The red wiggler (binomial name: eisenia fetida) is the world’s most common composting worm.

As a member of the epigeic  – Greek for “on the earth” – class of composting worms, red wigglers generally will not be found in soil. Rather, they thrive in and under leaf litter, manure, decomposing vegetation, and other organic matter.

Native to Europe, eisenia fetida are not classified as invasive species in North America as they are not considered to have a negative environmental impact in the wild.

Red wigglers are less commonly referred to as tiger worms, brandling worms, manure worms, panfish worms, and trout worms.

This species features a vibrant color with yellow banding and is closely related to the more uniformly-pigmented eisenia andrei.

A study suggests that the two can produce hybrid offspring, a phenomenon which should otherwise be considered impossible between most worm species.

Fun fact: The “fetid” part of the binomial name refers to what some say is a foul-smelling secretion the red wiggler uses to fend off predators. But I’ve been dealing with them for years and never noticed this!

Anatomy and Digestive Tract of a Red Wiggler

The anatomy of a red wiggler resembles that of other common earthworms; a long-segmented body begins at the pointed head and terminates at a slightly-flatted tail.

A fleshy band called a clitellum features prominently on the body of the red wiggler at roughly 1/3rd of the length of the worm.

The digestive tract is simple, starting at the mouth where the worm begins to consume its food before passing it on to the pharynx.

The pharynx is a muscular section which acts like a pump to pull food into the mouth before pumping it out into the esophagus.

The esophagus is narrow and thin-walled and acts as the “waiting room” for the gizzard.

The gizzard is the area where the food gets crushed and ground down before moving on.

Note: This need for grinding is why grit is recommended in a worm bin. The worm features no native grinding capability so the worm relies on ingested grit to help grind its food in the gizzard.

The stomach is where the first chemical breakdown of food happens with the help of a protein-busting enzyme. Calciferous glands in the stomach also serve to neutralize acidic foods passing through the worm’s digestive tract.

The intestine forms the longest part of the worm and is where the majority of digestion takes place via enymatic processes.

The castings eventually pass through the anus at the end of the worm as capsules coated with a biologically-rich mucus. (You’re not eating I hope.)

Reproduction and Life Cycle of a Red Wiggler

Red wigglers will intertwine around one another, exchanging sperm through their skin.

Red wigglers, like all earthworms, are hermaphroditic, simultaneously possessing both male and female sex organs, both of which are used in the reproduction process.

Two worms of the same species will intertwine around each other’s clitella, secreting sperm through their skin, eventually producing a cocoon. This cocoon will normally yield 3 worms and each pair of worms will produce 1-3 cocoons per week.

This lemon-shaped cocoon is about 1/8th inch wide, and starts as a yellowish color. It gets progressively darker until it hatches 21 days later. 

Within 42 days, these baby worms will reach sexual maturity as evidenced by the emergence of the clitellum.

A mature red wiggler can be expected to live between one to three years.

Why Red Wigglers Are the King of Composting Worms

pile-of-red-wigglers

The mighty red wiggler may be used as a bait worm for smaller fish or as a protein source for chickens and reptiles.

But its main use is for – of course – vermicomposting.

And as mentioned above, they are the most common composting worm in the world.

But why?

Well there’s probably not just one reason.

Rather, a combination of cost, hardiness, and comfort in a wide range of temperatures makes it the most appropriate composting worm for most new vermicomposters

Hardiness and Temperature Tolerance

red wigglers in ice crystals during cold weather
Red wigglers and their cocoons can survive in a wide range of conditions. (Image courtesy of Dr John Biernbaum, Michigan State)

Red wigglers are a resilient composting worm, tolerant of a wider range of temperature than other species.

For instance, its larger cousin, the European Nightcrawler prefers cooler temperatures in the high-60°F range. African Nightcrawlers, on the other hand, prefer warmer temperatures between 77°F and 86°F.

The red wiggler can tolerate both the low and high ends of these ranges, reproducing and processing organic waste well between 55°F-90°F.

They will survive – although maybe not thrive – temperatures well below 50°F.

Its cocoons are famously hardy as well, able to withstand prolonged freezing temperatures, staying viable in a suspended state until they are able to hatch in warmer weather.

Cost

Thanks to its adaptability to different climates and ability to reproduce quickly in them, the cost of red wigglers is consistently lower than European nightcrawlers and significantly lower than the African nightcrawler.

But red wigglers are nobody’s idea of cheap, and the skyrocketing demand for all things garden-related due to the COVID pandemic of 2020 boosted prices of all composting worms.

You can expect to pay at least $55 for one pound of red wigglers with shipping included in the continental US. As shipping two pounds is not significantly more expensive than shipping one pound, buying 2 pounds often provides the best value.

The amount you buy, however, should be dictated by the available surface area of your worm bin.

For most commercial worm bins, 1lb is sufficient, but 2 lbs will get you off to a faster start with your waste processing.

If buying in bulk, it’s possible to buy for less than $25 per pound when buying 10 lbs or more.

But most US suppliers are unable to fulfill large orders.

Red Wiggler Ownership: What You Need to Know About Ordering, Maintaining, and Feeding

Ordering Red Wigglers Online

There’s nothing cosmic about ordering worms online, but I highly recommend you either build a DIY bin or assemble your purchased commercial worm bin (hopefully the Urban Worm Bag!) before you order your worms.

You never know what problems or delays you may encounter with your worm bin, so it’s helpful to get it set up first to ensure you get off to a good start.

How and When Red Wigglers Get Shipped

When you do finally order your worms, it is likely that they will not ship until the following Monday. This is a common practice among worm shippers who don’t want to risk having the worms sit in a hot or cold warehouse over the weekend.

Worm growers are not storing worms in a situation where they are ready to ship. The worms must be harvested from their habitat first, so growers will often set a Friday or Saturday deadline in order to harvest in time for a Monday shipment.

As shipping live animals requires special permission from UPS or Fedex, almost all worm sellers ship via USPS Priority.

Worms are typically packed in dry peat moss, NOT a living habitat. This reduces weight, but more importantly, the risk of microbial activity raising the temperatures to deadly levels while the worms are in transit.

Interestingly enough, significantly longer distances do not necessarily mean significantly longer transit times.

Monday shipments from the East Coast often reach California customers on Wednesday or Thursday, and vice versa.

But transit times are dependent upon the efficiency of the US Postal Service in your area.

Your shipping boxes are likely too large to fit in a mailbox, which is a good thing as a summertime shipment would be doomed in a hot, poorly-ventilated mailbox.

So make sure that your postman is directed to leave your shipment in a shaded, protected environment if you won’t be home to receive your worms.

Where to Buy Red Wigglers

You can order from a number of online resellers, us included!

But if you’re ordering from PetSmart, PetCo, Walmart, or another large company that is not directly related to the vermicomposting world, be careful!

These worms will be A) expensive and in small quantities and B) quite possibly not eisenia fetida or composting worms at all.

To save on shipping cost, you may want to see if there are any nearby “Mom and Pop” stores through a Google search.

If you don’t find what you’re looking for, then I invite you to check out worms through the Urban Worm Company!

How Many Red Wigglers Should You Buy?

The amount of red wigglers you buy should be solely dependent upon the surface area you have available for vermicomposting.

As a rule of thumb, you should buy 1/2 to 1lb of composting worms per square foot of vermicomposting surface area. In the Urban Worm Bag, this would mean a 1 to 2lb purchase. For the Worm Factory 360 or one of the other stackable bins, 1lb is likely enough!

With the appropriate temperature, moisture, pH, and food sources as discussed below, you should achieve higher densities, perhaps 2-3 lbs per square foot or so.

But worms are expensive, so it’s a safer bet to start with a lower density and allow the worms to grow into their worm bin.

Maintaining a Worm Bin with Red Wigglers: Temperature, Moisture, and pH

I call these the “Big 3” factors of worm bin maintenance. If you keep all 3 within appropriate ranges, then there’s not *that* much that can go wrong with your bin.

Temperature

As mentioned earlier, red wigglers have a wide temperature tolerance. For best results, keep a temperature of 55°F-90°F.

Short departures out of that temperature range are fine.

While the ambient air outside of the bin certainly has an effect, what really matters is the temperature inside the bin. The worm and microbe activity in the bin will generate heat so you can expect a worm bin to be 10-20 degrees warmer in the winter.

The thermal mass of a large worm bin will also feature more protection against short-term temperature swings, so if you’ve got the option of keeping a large worm bin vs a small one, choose large every time!

Moisture

Moisture in the worm bin is the most-underrated factor in worm bin success and again, red wigglers don’t prefer it any warmer or drier than any other composting worm.

Please take this next statement to heart.

Most worm bin owners run their worm bins way too wet. And a properly-maintained worm bin should not be producing leachate.

Because so much water is bound us within the cells of fruit and vegetables, it doesn’t seem like your feedings are adding that much water. But they are. 

To be conservative, I would add bedding every feeding. This prevents a mucky, muddy vermicompost that will be simply difficult to harvest at best, and a stinky, anaerobic mess at worst.

For best results, you want to shoot for about 60-70% moisture level. The simplest test for this is to squeeze a handful as hard as you can.

At the perfect moisture levels – which is just under 70% – that handful should barely yield one drop of liquid.

pH

pH in a worm bin is pretty easy to maintain.

Vermicompost should normally be slightly acidic – in the 6 to 7 range –  and can be maintained with constant additions of bedding.

If needed, ground eggshells and agricultural lime can be used to offset the the generally more acidic fruit and vegetable waste.

Unless you only feed acidic food waste, which will cause all sorts of other problems, pH is likely going to be the least of your concerns when it comes to maintaining your red wigglers

Feeding Your Red Wigglers

Red wigglers don’t need a different diet than any other composting worm, but the following point can’t be stressed enough; a properly-maintained worm bin will need regular additions of bedding along with food waste.

Worm bedding, unlike bedding for reptiles, hamsters and other animals, will ultimately be consumed by the worms as it breaks down.

In this respect, carbon-rich bedding is a “slow food” where food waste is a “fast food.” And when feeding your red wigglers, we recommend a 2:1 ratio of bedding to food waste, by volume.

In other words, if you’ve got a handful of food waste, add at least two handfuls of bedding.

But when choosing the fast foods for your red wigglers, stay away from meat- or dairy-based products. Otherwise, you’ve got plenty of options in front of you.

Within reason, most fruits and vegetables are fair game and your red wigglers will be thrilled with them.

Want to Learn More About the Soil Food Web?

Fungi are crucial “characters” in what we know as the soil food web.

Check out what everyone else does in our comprehensive post about what else is under your feet.

Summary: The Ford Taurus of Composting Worms

There are excellent vermicomposting worms that you can choose from. The European Nightcrawler, the larger cousin of the red wiggler, is just as voracious and also makes for a good bait worm. But it prefers a bit of a cooler environment than the red wiggler.

The African Nightcrawler is a very large composting worm and makes a beautiful, granular cast.

But it needs warmer temps than the eisenia fetida. The Indian Blue is voracious, but also prefers a warmer climate and it also exhibits a tendency to escape the bin.

The red wiggler is a hardy worm and isn’t as picky about its climate. I like to call it the Ford Taurus of vermicomposting worms; you won’t brag to your hardcore composting buddies that you own them, but they will serve you well.

They are simply the most appropriate worm for the widest range of circumstances.

If you’re just getting started with vermicomposting and in need of some mighty red wigglers or you need a “top off” for your bin, I’d love for the Urban Worm Company to earn your business!

27 thoughts on “Red Wiggler Composting Worms: Everything You Need to Know

    1. Hi Terry,
      I’m not sure I have enough information to know, but it would be strange that the worms are thriving enough to reproduce but then also dying. I think you’re using the coco coir for bedding but can you tell me what your feedstock is?

  1. Excellent source of information. Thanks so much. I may be back to pick up one of the bags. I’m not sure how well it will work outside in Mesa, AZ with simmer temps near 110 and a sun that destiys webbing (from woven non-fabric pots in 3+ months. Of course these would have tobe in the shade.

    1. Thanks Keith! And yeah, I don’t recommend keeping the UWB outdoors where it would be exposed to direct sunlight and/or precipitation!
      Cheers,
      Steve

  2. I have two large composting bins. Not worn composting bins. They are super full of food not yet broken down and too full to turn. I was thinking of adding red wiggles for quicker breakdown. Thoughts???

    1. Hi Fran,
      I’m going to give you a partial thumbs up on this idea.
      If the hot compost bin is an open air system, then yes, you could give this a shot. But in an enclosed system like a tumbler, this would almost certainly kill the worms because they won’t be able to escape the heat.
      Cheers!
      Steve

      1. Hi Steve,
        Thank you for your informative article. I have thousands of thriving red wigglers in a system I made out of Rubbermaid bins. I feed them almost all of our fruit/vegetable scraps, except for onions, citrus, pineapple, and tomatoes, and I leave out seeds as well as I reasonably can. I add all of our coffee grounds, pulverized eggshells, and chunks of corrugated cardboard for bedding (about 1:1 by volume with food waste). My only problem is how to harvest the castings, which are plentiful, but chock full of worms.
        My other observation is that I put all of my other scraps, which I consider to be not worm-friendly, in a black 12-cubic-foot compost tumbler, ventilated, but otherwise a closed system. Somehow, it is rife with worms that I did not add to it (deliberately, anyway). If they like it there, more power to them. I think they may be earthworms. It is in a partly sunny location, and gets pretty hot in the summer, but the worms don’t seem to mind.
        Any thoughts?

    2. I have overfed (food scraps, you cant overfeed cardboard, lol) and wound up with a bin that killed off most of the worms and the rest were trying as best they could to escape. The food creates a VERY acidic environment when it is breaking down and that was the issue. I solved it with a few handfuls of DOLOMITIC lime (VERY important to use correct type). Now that bin is thriving. If your bin is ‘super full’ of food then you may want to keep this in mind.

  3. I heard that red wigglers don’t like vibration so I purchased the WB2 and the best spot for me to put it is in my utility room that has a treadmill on a separate from the floor plywood base 1hour use a day 5 days a week, walking only and a dryer that is used about 6 hours a week, other than this the room is quiet. The vibration from the treadmill isn’t bad from my perspective, barely noticeable, the dryer slightly more intense. Your thoughts before I start adding things? Thank you in advance

      1. Thank you for the prompt response, now I don’t have to listen to ” you’re not putting worms in the living room.”

    1. I live in southeast Texas so it gets pretty hot. I move my worm bin into my house in the summer & winter when it gets to cold. I have them in a foam cooler. Do you have any suggestions that are better than what I’m doing?

  4. Just getting started, I live in Wisconsin where the winter temps can get in the negatives. I was thinking about putting this in the garage year-round. Will the temps we get be too cold? Also if it does get too cold was thinking of putting it in the basement. But, with the food and worms will it produce a smell that I won’t want in my house?

    1. Welcome to the world of worms, Sue! The garage might be OK, but indoors is always better. And no, if you’re not feeding too much, then there should be no fouls smells coming from the bin!
      Cheers,
      Steve

  5. my worm bin has been in operation for approx. 6 months. It is now starting to smell and there are hardly any worms compared to 2 months ago. The bin is a large Tupperware tub with no top. Holes in the bottom do not produce any leachate. I place a loose black garbage bag over the dirt in the bin to keep the bin dark otherwise the worms crawl out. The dirt is about 6 inches deep

  6. Hi Steve:

    If my worms are climbing the walls of my bucket, is that a concern? I’ve been bringing home coffee grounds from work, but intermixing those grounds with saw dust… if the worms are along the sides, is this an indication of concern?

    1. Hi Tom. Worms crawling up the walls aren’t necessarily an issue unless it’s an obvious mass exodus. Sometimes a part of the population can be found in balls on top of the material or on the walls of the bin… It sounds like you will want to add some other feedstocks. Excessive amounts of coffee grounds can cause acidic conditions in the bin which pose a risk of protein poisoning, or sour crop, in the worms. Sawdust has an extremely high carbon to nitrogen ratio meaning it will take a long time to break down. Both sawdust and coffee grounds are small in particle size which means there won’t be much space for oxygen which is essential to keep conditions aerobic. Try mixing in some other brown and green material. Food scraps along with some shredded newspaper or shredded straw should help. If you continue experiencing issues holler back at us.

  7. I purchased 100 red wigglers and rec’d 147, back in early April 2022. There are many tiny worms, so I know they are reproducing. I’ve been chopping vegetable and fruit scraps into tiny pieces but using a grinder to crush egg shells down smaller than my rolling pin did. Would it be okay to grind the veg and fruit waste to feed also instead of chopping? Also, I’ve been adding crushed egg shells with every other feeding, is that too often, not often enough, or does it make a difference? (I clean the shells, let dry, then microwave 4 minutes, let cool, then crush). I sprinkle about 2 Tbsp on top of the food scraps every other time, so about once per week as I feed food twice per week with lots of shredded cardboard and wet coffee filters with only remnant grounds clinging. The worms seem very happy with this arrangement.

    1. It should work well to grind your food scraps and egg shells. I think adding some eggshells every other feeding is totally fine. It isn’t necessary to clean them. Any residual egg or albumen will feed microorganisms. Just let them dry out and crush them.

  8. I’ve had my worms for about a month now and they have begun to be very sluggish. Any ideas why? I’ve fed coffee grounds, tea bags, carrot scraps, apple scraps, newspaper, Peet moss for beading.

    1. Hello
      The typical reason that worm activity slows is due to temperature in the bin. Too cold or too hot of temps will make them slower to work through material.

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