Will a Red Worm Population Double in 3 Months?

One bizarre vermicomposting “fact” that has been floating around for years, and taken seriously by many newbie vermicomposters, is this idea of expecting your Red Worms to double in number in 3 months (or “90 Days”). It seems like a fairly reasonable claim on the surface – but if you really sit down and crunch the numbers you’ll realize pretty quickly just how utterly ridiculous it is!

For starters – even regardless of any fun calculations you can make (something we’ll do in a minute) – it’s hugely important to remember that Red Worm reproduction and growth are both HIGHLY dependent on a wide range of different factors. Some of the most important include 1) temperature, 2) moisture content, 3) population size, 4) food value and overall availability.

But just for fun, let’s crunch the numbers anyway!

For our little thought experiment, we are going to assume that we’re starting with
100 adult Red Worms

Some Other Important Assumptions

– Fairly close to “ideal” conditions – 25C / 77F temps – good moisture, ample nutrition etc
– 3 cocoons produced per adult worm per week*
– 3 juvenile worms hatching from each cocoon*
– 21 days incubation time until cocoons hatch*
– 42 days to maturity*
– 12 week period – with final tally being made at the END of these 12 weeks (still, technically a little less than 3 months)
– For sake of simplicity we are basically assuming that all cocoons are dropped at the end of each week – so each cohort will hatch/mature at the same time. This is obviously not how it would happen (cocoons would be laid throughout week) – so our final tallies are actually going to be lower than they should be.
– There are NO worm mortalities during the 12 weeks

*These figures are based on those shared at the end of this post: Crazy Q&A Podcasts – Session #13 (most closely resembling the figures calculated by professional worm farmer, George Mingin)

NOTE: What is listed under each week is what we’ll expect to be present at the beginning of that week


WEEK 1


100 Adults


WEEK 2


100 Adults
300 Cocoons (A)


WEEK 3


100 Adults
300 Cocoons (A) – 7 days old
300 Cocoons (B)


WEEK 4


100 Adults
300 Cocoons (A) – 14 days old
300 Cocoons (B) – 7 days old
300 Cocoons (C)


WEEK 5


100 Adults
900 Juveniles (A)
300 Cocoons (B) – 14 days old
300 Cocoons (C) – 7 days old
300 Cocoons (D)


WEEK 6


100 Adults
900 Juveniles (A) – 7 days old
900 Juveniles (B)
300 Cocoons (C) – 14 days old
300 Cocoons (D) – 7 days old
300 Cocoons (E)


WEEK 7


100 Adults
900 Juveniles (A) – 14 days old
900 Juveniles (B) – 7 days old
900 Juveniles (C)
300 Cocoons (D) – 14 days old
300 Cocoons (E) – 7 days old
300 Cocoons (F)


WEEK 8


100 Adults
900 Juveniles (A) – 21 days old
900 Juveniles (B) – 14 days old
900 Juveniles (C) – 7 days old
900 Juveniles (D)
300 Cocoons (E) – 14 days old
300 Cocoons (F) – 7 days old
300 Cocoons (G)


WEEK 9


100 Adults
900 Juveniles (A) – 28 days old
900 Juveniles (B) – 21 days old
900 Juveniles (C) – 14 days old
900 Juveniles (D) – 7 days old
900 Juveniles (E)
300 Cocoons (F) – 14 days old
300 Cocoons (G) – 7 days old
300 Cocoons (H)


WEEK 10


100 Adults
900 Juveniles (A) – 35 days old
900 Juveniles (B) – 28 days old
900 Juveniles (C) – 21 days old
900 Juveniles (D) – 14 days old
900 Juveniles (E) – 7 days old
900 Juveniles (F)
300 Cocoons (G) – 14 days old
300 Cocoons (H) – 7 days old
300 Cocoons (I)


WEEK 11


100 (original) Adults
900 Adults (A)
900 Juveniles (B) – 35 days old
900 Juveniles (C) – 28 days old
900 Juveniles (D) – 21 days old
900 Juveniles (E) – 14 days old
900 Juveniles (F) – 7 days old
900 Juveniles (G)
300 Cocoons (H) – 14 days old
300 Cocoons (I) – 7 days old
300 Cocoons (J)


WEEK 12


100 (original) Adults
900 Adults (A)
900 Adults (B)
900 Juveniles (C) – 35 days old
900 Juveniles (D) – 28 days old
900 Juveniles (E) – 21 days old
900 Juveniles (F) – 14 days old
900 Juveniles (G) – 7 days old
900 Juveniles (H)
300 Cocoons (I) – 14 days old
300 Cocoons (J) – 7 days old
300 Cocoons (K)
2700 Cocoons (A-1)


FINAL TALLY (END of WEEK 12 | Beginning of WEEK 13)


100 (original) Adults
900 Adults (A)
900 Adults (B)
900 Adults (C)
——————————–
900 Juveniles (D) – 35 days old
900 Juveniles (E) – 28 days old
900 Juveniles (F) – 21 days old
900 Juveniles (G) – 14 days old
900 Juveniles (H) – 7 days old
900 Juveniles (I)
——————————–
300 Cocoons (J) – 14 days old
300 Cocoons (K) – 7 days old
300 Cocoons (L)
2700 Cocoons (A-1) – 7 days old
2700 Cocoons (A-2)
2700 Cocoons (B-1)
—————————————————————–

TOTALS

2800 Adults
5400 Juveniles
9000 Cocoons

SO…

We’re looking at a potential 28-fold increase in the number of adults alone!


Of course, a typical worm bin probably won’t see growth rates like the ones shown above since people often start with a fairly large quantity of worms in a relatively small container. BUT, it really does give you some idea of what’s potentially possible if you give the worms plenty of space to spread out in, and just generally take good care of them!

Bottom-line – it’s safe to say that unless you are really messing up, you should definitely expect to see much more than “doubling” of your Red Worm population (especially if you are counting juveniles) within a few months!

🙂

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Comments

    • Jim
    • August 9, 2022

    I use aged horse manure/shavings in my worm bin. No cardboard or paper, but I do add scrap fruits and veggies.
    I started with 1 lb of worms in a plastic 24 x 14 storage bin.
    In 4 weeks there were so many worms I poured that into my 4’x8’ CFT bin. More horse manure and food scraps. At 8 weeks I turned the 4×4 into a 4’ x 8’ CFT worm bin. Right now is 11 weeks and there are literally thousand upon thousands of adults and juveniles in the bin.
    The aged manure is critical for me because there is no way I can produce enough food scraps
    But I just wanted to say, in the right environment you can easily get 10-15 times the worms in 3 months.
    In 12 months I should have 200-300 lbs of worms and hope to be selling 1000 worms $35 + shipping.
    I already have 2 more 4’x8’ bins going and all the aged horse manure I can handle. Could be a money making hobby.
    Wish me luck

    • Bentley
    • August 9, 2022

    Hey Jim
    You’ve hit on some really key points here – thanks for sharing your experience. Using horse manure, and continuing to give your worms more room have likely played a very key role in helping your population grow so quickly. And I agree about the potential to (AT LEAST) 10X within a few months.
    😎

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