How Many Worms Is Enough?

A lot of people who are thinking about getting into vermicomposting wonder (understandably) what quantity of worms they should start with. There are plenty of recommendations out there but really, no one suggestion is necessarily better than the next. As such, I thought this might make for a good topic of discussion.

In a nutshell (and in my humble opinion), the quantity of worms you start with entirely depends on what you are trying to do, and how quickly you are trying to do it. I’ll be honest – I used to wholeheartedly subscribe to the idea that worms should be allowed to “grow into their system”. In other words, you start a bin with relatively low densities of worms (less than the standard ‘1 lb per square foot’ recommendation), and simply allow the worm population to gradually increase over time, presumably reaching a ‘carrying capacity’ for the given system at some point.

I definitely still see value in this approach, but now that I have my own worm business and have played around with dense concentrations of worms, I’ve come to recognize the composting power of putting a LOT of worms in a relatively small system! You may recall the post I wrote after putting 5 lbs of worms in a “holding bin” for a couple weeks while I was away this past Spring (see “5 lbs of Red Worms – WOW!”). When I arrived back home I couldn’t believe how thoroughly they had processed the upper levels of bedding and food waste. I also couldn’t get over the number of cocoons I found.

For anyone interested in building a large population for their own use or to sell, this is definitely something to consider. I ended up harvesting a large proportion of the worms in the ‘holding system’, but it is now crawling with countless juvenile worms that hatched out from all those cocoons. I suspect that keeping worms so densely packed not only increases the opportunity for mating (they certainly don’t need to look far for a partner), but it also triggers the breeding urge to help protect against the possibility of a population crash (something that might occur in a ‘wild’ population). If you set up a series of identical bins and then simply moved most of your adult population from one bin to the next – leaving them to sit for a couple weeks in each – you could potentially end up with a serious worm nursery (good thing they don’t need diaper changes – haha), while still maitaining a large proportion of your original stock.

Anyway, I’m kinda going off on a tangent here…

Back to the topic of ‘more vs less’. Let’s look at a breakdown of the advantages/disadvantages of starting with more worms.


  • Greatly increased processing power – more waste materials can be added, and less lag time between feedings
  • Less issue with ‘pest’ organisms since they are generally being outcompeted by the worms
  • Less chance of odours developing since the worms are actively aerating and consuming material – also less chance of poor conditions developing in general (for the same reason)
  • Finished castings produced more quickly
  • Great way to build up a larger worm population

  • Costs more money initially
  • Much more important to provide excellent habitat for worms
  • If something goes wrong, it goes wrong in a BIG way
  • Potentially more tendency for worms to roam (but again comes back to importance of excellent habitat)

As I’ve discovered many times myself, when you start small there is a much greater chance that other worm bin inhabitants will become ‘major players’ in the system, thus potentially limiting the upper size limit of the worm population. It can also be frustrating for a newcomer to sit and wait for their worms to get settled in and then grow in numbers before being able to REALLY witness the true power of vermicomposting. Don’t get me wrong – this approach may be perfect for some.

If you are a person who really wants to test out vermicomposting, but you don’t mind (or you even prefer) doing so in a leisurely manner, then starting small is the best way to go. Just set up a bin add a small batch of worms or even cocoons for that matter, and then simply add food materials every once in awhile (or don’t add any more food at all – the worms will consume all the bedding if the ‘normal’ food supply gets cut off, and will likely be totally fine for months).

If on the other hand you need (or at least want) results FAST, then starting with a larger population is definitely the way to go. In some ways, I suspect that many of the newcomer nightmares would be avoided if people simply set up their system well initially and added a decent quantity of worms. There would be less chance of overfeeding – which alone leads to many other issues – such as pest populations, anaerobic conditions, fungal spore production etc – and people would more quickly see how cool vermicomposting is. This approach does require more involvement though – so it’s a trade-off!

Anyway – just my thoughts on the matter. I’d be interested in hearing what others think about all this.

[tags]worm composting, composting worms, red worms, worm bin, worm bed, worm density, worm breeding, worm reproduction, worm farming[/tags]

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    • Sherry
    • July 30, 2008

    Hi Bentley,
    I started out with 1 lb, lost most due to an unfortunate accident, then bought 5 lb. I decided very early on that 1 lb wasn’t going to consume the amount of food we can create for them. I do have my worms divided out into 4 bins, some with more worms than the other.

    That would be a very interesting experiment…..moving the worms into 1 bin for a few weeks, then on to the next. I never would have thought that. It wouldn’t be simply upending the bin into another, would it? I definitely want to try this. Maybe having a large bin population might keep my mite problem at bay that I currently have in one bin?

  1. Bentley,

    Interesting blog! I can’t say I have ever seen this topic discussed as well as you have written here.

    Vermicomposting with a small amount of worms is like trying to dig a swimming pool with a shovel! 😉

    I gotta run, I have basketball sized green squash that need tending to.

    Thanks Worms!

    • Dwayne Clark
    • July 30, 2008

    Hey B

    On that topic I raised about when to harvest:: This question about how many worms is right crossed my mind. I wondered if I had started with more worms would I have been further along. I speculate yes but I am glad I started smaller land let the worm acclimate and reproduce. The bin seems very healthy and it is getting there just a little slower than I thought. Of course it has been brutally hot which may have slowed them down on eating too.

    Good post and I did pass it on to some others in the as they had questions about this.


    • vermiman
    • July 30, 2008

    When starting small, I would suggest that the container be started small which should allow the worms to find each other easier.

    • Bentley
    • July 30, 2008

    Thanks everyone for chiming in! Clearly this is a topic that gets people’s attention!

    Sherry, my nursery idea would definitely require more than simply dumping each bin into the next, so it would require some work (separating worms each time) for sure. You would want to leave all the material/cocoons in each bin after the worms have gone to work in it so it could then become a worm nursery. You’d obviously lose some of your adults in each of the bins, but I would imagine you’d still be able to separate quite a few from your final bin (assuming you didn’t just leave them in that one)


  2. so.. all that said… “starting small” assuming a regular rubbermaid bin was the home… would be 1/2lb? on the vermicomposting forum someone thought that around 2lbs would be about right for numbers in a bin…(used some formula?)

    hmmmm…. I like the nursery idea…

    • Karen
    • July 30, 2008

    I started a small worm bin about two months ago with a small container and not too many worms (around 1 lb). I have been disappointed with their slow progress and keep rooting for them to reproduce since they’re not keeping up with how much I am feeding them. I didn’t realize how much food waste I was throwing out before but it is a lot more than I thought! I haven’t noticed any odors or other problems (besides some ants) so I have been just letting them be. I think your post convinced me to just buy more worms to get the results I want!!

    • Jill
    • July 31, 2008

    I started with one pound of worms last August in a small home made bin and estimate I have around 10-12 pounds now in a wigwam.

    The great thing I found by starting small was it gave me lots of time to plan and research what was best to do next. I am starting a small business for castings, and my slow moving worms gave me plenty of time to take classes, talk to others, read books about it, etc., etc.

    • Bentley
    • July 31, 2008

    Wow – this really seems to be a popular topic of discussion. Thanks everyone for sharing your thoughts.

    Jill – you’ve made some excellent points! When someone is thinking about starting up their own worm farming business I almost always recommend starting small (although starting small in that case could mean 5 lbs of worms instead of 100 lbs). Great to hear that you were able to build your population up like that. Should be interesting to see how many worms you have by NEXT year!

    • Sherry
    • July 31, 2008

    Hi Bentley,
    I took all of the worms out of my bin with the mites (they’re relieved!) and put them in another. I then took a chunk of styrofoam and divided my bin some more. There should be a huge difference now in future population, now! And they don’t have to wander to look for someone when they get the urge!

    • Susan
    • July 31, 2008

    There seem to be multiple definitions for ‘starting small’. I went to a workshop that started us each off with 1 oz of worms in a plastic planting pot that probably holds about 3/4 of a gallon. I splurged and got 3 oz. It was slow going, but 7 months later I have more than a pound. They still don’t eat everything I produce, but that will come. I guess I’m doing the ‘minimalist’ and ‘frugal’ style of vermicomposting. 🙂 I’ve been able to start 4 friends with a few oz. each along the way. I can easily tolerate giving away a few oz. I wouldn’t want to give away a half a pound.

    Cut the top off of a plastic container for a gallon of milk and poke a few holes in the bottom. Set on an old plate or folger’s can lid and lay another lid over the top. When it’s that small, the other critters can’t take over before the worms are established.

    • Bentley
    • August 1, 2008

    Sounds good Sherry – I’d recommend adding lots of shredded newsprint or cardboard bedding as well. These seem to help stimulate reproduction.

    Susan – you are certainly right, and you seem to be one of the “patient” people who enjoys taking your time with vermicomposting.
    An entire worm population could literally be started with a single (viable) cocoon if you didn’t mind waiting! Hey, that sounds like an interesting experiment!

    • Sherry
    • August 1, 2008

    “An entire worm population could literally be started with a single (viable) cocoon if you didn’t mind waiting! Hey, that sounds like an interesting experiment!”

    LOL………I sense updates on a new experiment in the near future!!!

  3. Great article, I was curious about using a larger amount of worms for my boxes to increase their population. I’m wanting to sell vermicompost produce by my Red worms and Euros for bait.

    May your bins and boxes thrive everyone.

    • Patrick
    • February 13, 2010

    Hey Bentley,

    Wondering how things are going now with the dense concentrations.

    • Bentley
    • February 16, 2010

    Hi Patrick,
    I don’t have any systems with really high densities of worms at the moment. Over time (assuming you don’t remove some worms to sell or stock another system) the population to adjust itself based on available space and food.

    • Tom
    • October 10, 2010

    for the life of me I cannot see any cocoons. I
    ve read descriptions, seen photos but STILL can’t see the little varmints. I’ve had my worm since June 2010

    • Frank
    • November 29, 2010

    Hi Tom,

    I have seen few cocoons in my bins as well. The food goes in, disappears, castins appear but few if any cocoons. I am sure conditions are not quite right, but it is a frustrating wait. I will keep at it.


    • Lulu
    • July 8, 2012

    HELP !! they won’t slow down multiplying!
    This is my 3rd year with them. They are good workers and eat more waste than I can produce. I actually collect waste from my neighbor to keep them fed. I encourage fraternization, but they don’t use any birth control !!!
    The DNR lecturer said not to let them loose in our environment. So how do I control the population??? They are captive slaves, I want to be fair.

    • Bentley
    • July 9, 2012

    Sounds like a “good problem”, Lulu. My suggestion would be to give a lot of them away. Maybe put an ad in Craigslist, or better yet, post something on the Vermicomposters forum and/or provide me with your location and I can post here on the site. I’m sure we could track down someone willing to help ease your vermi-burden.

    • Nat_Bee
    • November 21, 2012

    I am just starting out and before finding red wigglers, had purchased a larger tupperware bin (53L, basically big enough for about a pound of worms give or take) Now everything is basically set up with compost and bedding and drilled holes and the works). I finally managed to find some red wigglers from a friend of a friend, but when I picked them up, there were only a few ounces! Wondering if I should put my worms in, or just pay the 60$ or so it would take to ship wigglers to my area :S Should I put the wigglers in a smaller container? How long would it take them to multiply? Kind of looking forward to getting started before winter… Not too worried about them eating all of my waste, I have a regular outside compost, but hoping to get some compost by late spring early summer to throw in the garden… Thoughts?

    • Melissa
    • February 11, 2013

    I started composted about a year ago and couldn’t be happier with the results. I now have four bins in my basement and have had to resort to asking friends/family for their food scraps because I’m not producing enough. I have found that a mixture of leaves, shredded newpaper and carbord seem to make an ideal environment for my worm but still need to periodically add additional water to bins as it does seem to dry out at times. This summer is the first time that I have enough castings to put into my garden and I’m excited to see how my vegetables do this year. As a thank you to my worms, I’m planning on planting pumpkins just for them to eat. They just love pumpkins and I will find 100s of them in one spot just eating away. Thank you for the helpful information that you have shared on this site.

    • bob
    • April 26, 2013

    Because if they lay 1 egg per day and i kept adding a tub every 2 or 3 weeks couldn’t i really speed up the process by making like a nursery in the long run? Because if breeding worms lay 1 egg per day you would think you could do allot better Im confused

    • pat fale
    • July 14, 2015

    how many pounds of castings will 500 worms produce per month

    • Bentley
    • July 16, 2015

    Hi Pat
    Unfortunately, that is next to impossible to predict since there are so many different variables that can affect this. Hugely important factors include temperature, aeration, moisture content, the type of food you are adding, the C:N ratio, and how well you optimize everything.

    You should also expect to go through a “priming” period, of perhaps 2-3 months, before you can even start harvesting (the good news is that your worm population should at least increase a lot during this period).

    With a system like a Worm Inn (or other flow-throughs) you should reach a point where you can continue removing castings on a fairly regular basis. With a plastic bin it will probably be more of a periodic batch harvest every few months (although, if you really wanted to, I’m sure you could get away with digging some out of your bin every month).

    • craig
    • September 12, 2015

    Hi, I’m here formally introducing myself as a newb (commencing yesterday 😉 )
    I went around to bait and fishing shops yesterday and managed to pick up a few worms myself. I realm anticipating using them only for helping grow potatoes until the worker at the shop said that these worms are rather scarce around the place I stay, so…i have a first buyer…already 😉
    Where do you buy something and the shop says they’re willing to buy from you if you produce?
    So I’m now taking advantage, lets see how it goes)
    First customer and I haven’t even started yet)

    • David Garcia
    • May 30, 2019

    This site is an incredible resource. I am a longtime gardner but a fairly new (like a few weeks) to vermicomposting. It has been amazing.

    I started with two buckets — each with a population of about 1k. I then created a new bin for vertical migration using heavy duty 17-gallon bins. I also added about 1-2k new worms yesterday that someone gave me.

    So, I have about 3-4 k munching away. I have a pH monitor and a moisture monitor, and believe it or not, my first bin is about 70% full, and I am asounded by how fast they eat. After reading this post (which does answer my “how much is too much, how few is too few” question, I am pretty excited to add another 2 k, which will bring this bin to 5-6 k. I fed them two days ago, and then today, I used a ninja blender to chop and then strain a bunch of bean sprouts and lettuce. I then shredded a whole bunch of new brown paper bags and added the damp (strained pulp) to some dry shredded newspapers.

    This is amazing

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