Which came first - the Red Wiggler, or the cocoon?
Earthworm Cocoons
Without delving into philosophical rabbit holes, life begins for an individual red wiggler worm inside of a cocoon.
An earthworm cocoon itself is not an egg, but more similar to a capsule to protect fertilized worm eggs inside of it. Baby earthworms spend as little as 18 days in these cocoons before hatching, but can also spend several months, and possibly years, while waiting for ideal conditions to hatch.
On average, around 3 baby worms will come out of each cocoon, but as many as 7 babies can come from a single cocoon.
Cocoons, when laid, are white and almost transparent, but quickly darken to a yellow color. When the worms are about ready to hatch it will get even darker, appearing like a dark yellow-brown. Just before they hatch, you will be able to see the baby worms wiggling around inside of them.
Cocoon Identification and Size
Cocoons are typically around 1/8th inch, but their size can vary a bit. For most of the worms incubation time, the cocoon will appear yellow and slightly translucent, but will become darker with time.
The cocoons are mostly spherical besides a tapered end - where the baby earthworm will eventually exit the cocoon.
The picture below shows red wiggler cocoons next to a tape measure for scale.
And here is a picture showing the different colors of cocoons against a white sheet.
Earthworm Growth - The Teenage Years
Baby Red Wigglers are very small, and can be difficult to see. In this picture you may see the worm on the right, but if you look even closer, there is a pretty newly hatched baby worm on the left.
My pointer finger for scale - sorry I did not have a banana!
For the next 40-60 days, the worms grow bigger and fatter as they eat, becoming hundreds of times heavier than they were at birth.
If worms are not malnourished, after this time they become "clitellate." This means they now develop a visible "clitellum" which indicates sexual maturity.
Adulthood and Reproduction
Sexually mature adult red wigglers are easily identified by their clitellum - the band around the earthworm's body towards their head.
Red Wigglers, and all earthworms, are hermaphrodites! They have both male and female reproductive organs. The clitellum is similar to human ovaries as it stores the unfertilized eggs of the worm.
The male reproductive glands are on the underside of the clitellum, but are small and difficult to see.
During sexual reproduction, two worms will line up their reproductive organs to be able to exchange reproductive fluids to each other. Both worms will get 'pregnant' from the encounter.
After the exchange of fluids, each worm will excrete mucus from its clitellum that will be sloughed off to form a cocoon, carrying fertilized worm eggs with it.
For a quick video of what this looks like, watch here: https://youtube.com/shorts/e8e6Ouw5WRw?feature=share
How Fast Can Red Wigglers Reproduce?
Pretty Fast.
In laboratory conditions, Eisenia Fetida have been found to be able to produce up to 3 cocoons per worm per week.
At the rate of 3 cocoons per week, and 3 babies per cocoon, red wigglers can reproduce as fast as multiplying their population by 9 times each week!
Note that this is under total ideal conditions, and this level of efficiency is mostly just theoretical. Realistically, you can expect your worm population to double after 2-3 months.
Theoretical Worm Population Charts
But lets have some fun with theoreticals! This is a chart representing their reproductive output assuming totally ideal conditions starting with only 500 worms:
The first 15 weeks are easy to wrap your head around. 500 worms becoming 50,000 isn't bad! But shortly after, when the growth become exponential, things get crazy.
Right around the 25 week (6 month) mark you could theoretically reach 2 and a half million worms.
And after 34 weeks, you could reach 80 million worms.
And after a total of only 46 weeks you could, theoretically - and really only theoretically - reach 1 billion worms.
Lifespan of Red Wigglers
The total lifespan of a Red Wiggler has not been thoroughly researched, but is a matter of years rather than months or weeks.
Red Wiggler Size
As previously mentioned, Red Wigglers naturally do not grow much bigger than 3 inches. The more nutrient dense, wet, and less crowded their environment is, the bigger they will get. A well fed worm can get as heavy as 1.2 grams!
