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
The red wiggler (binomial name: eisenia fetida) is the world's most common composting worm.
As a member of the epigeic – Latin 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, 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.
A mature red wiggler can be expected to live between one to three years.
Check Out the Urban Worm Calculator
If you're curious how quickly red wigglers can reproduce, check out the Urban Worm Calculator. With data input like assumed reproduction rate, financial value, mortality, harvest rates, etc, the Urban Worm Calculator will help you figure it out!
Why Red Wigglers Are the King of Composting Worms
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.
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 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.
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.
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 $48 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 $20 per pound when buying 10 lbs or more.
But as of this publication in late 2020, most US suppliers are unable to fulfill large orders.
Read this article to be able to tell the difference!
Red Wiggler Ownership: What You Need to Know About Ordering, Maintaining, and Feeding
Red wigglers can be ordered from most online worm retailers. It may be helpful to check the Urban Worm Network to find small businesses nearby who offer red wigglers without the significant cost – and risk – of shipping.
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 my Georgia-based preferred supplier often reach California customers on Wednesday.
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.
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.
Or you can check out out the Urban Worm Network, an interactive map of vermicomposters and vermicomposting-related businesses where you might be able to find worms for local pickup.
Make sure to uncheck the “Show Vermicomposters” checkbox so you can see only the suppliers nearby. You can also search your location in the search box.
If you don't find what you're looking for, then I invite you to use my trusted supplier for red wigglers!
Check Out the Urban Worm Network
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!
How Many Red Wigglers Do You Need?
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.
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 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 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 about 70% – that handful should barely yield one drop of liquid.
The articles below make the case for running a drier worm bin and how to precisely measure the water content of your worm bin or compost bin.
How to Measure Moisture in Compost
Moisture in the Worm Bin, Revisited
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.
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.”
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.
The article here (and linked to below) is a pretty good rundown of what you can feed red wigglers.
What To Feed Your Red Wigglers
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 and our trusted supplier to earn your business!