Can Worm Cocoons Be Effectively Harvested?

I recently received a couple of similar questions from “Gail” and “Kevin”. This is a topic that a lot of people seem interested in.

When I try to separate my worms from the compost I cannot
remove all the eggs and then I give up and put the worms back. Do eggs
have to be sacrificed? It seems mean, but I want my compost!

I harvested my bins for the first time this week.
Do you have a better method for harvesting cocoons than picking them out one at a time.

Hi Gail/Kevin,
You have touched on one of the major dilemmas of vermicomposting, and something I’ve yet to see a really good solution for. As nice as it is to produce and use beautiful worm compost that we’ve made from “waste” materials, it’s not much fun to see all that “future worm composting potential” end up potentially lost.

I personally don’t worry about this issue as much as some, simply because I happen to have a very extensive network of worm composting beds closely associated with my gardens. As such, I know that any baby worms hatching out will end up finding a good “home” quite easily and quickly. I realize that not everyone has the desire, or even necessarily the ability to dig a big network of vermicomposting trenches (it can involve some serious labor), but something you MIGHT want to consider, assuming the compost is being used in your own garden, is a smaller pit-type system associated with each plant (or a small group of plants).

Just to give you an example of what I mean here – this year I planted a couple of small boysenberry bushes in a heavy-clay-soil garden I have not done much with (as compared to a lot of my other “vermi-gardens”, anyway). When I planted each of them, I started by digging a really big hole. Next I filled it most of the way with a coarse vermicompost material, containing lots of cocoons and even worms. Then – after planting the bush and adding more vermicompost – I added quite a lot of alpaca manure over top. Finally I covered everything with a thick layer of straw. You certainly wouldn’t need to use alpaca manure (or manure in general) though – food waste could work as well. It would have the added benefit of providing slow release moisture in addition to being a worm “food” source.

Getting back to the original topic

HOW you are creating your vermicompost will likely have an impact on the ease with which you are able to separate the cocoons. In a plastic enclosed type of system, generally you will end up with a pretty mucky material which will obviously make it really difficult to do any sort of separation (even from the worms, for that matter – but be sure to check out some of the different approaches mentioned in the Harvesting section on the HOT TOPICS page for ideas about how to do that).

Vermicomposts produced in a really well-aerated system, especially some sort of “flow-through” bin/bed, will tend to produce a nice, crumbly vermicompost that should be a lot easier to screen. Start with a bigger mesh size (say 1/4″) and work your way down (anyone out there tried 1/16″?? I’ve meaning to). It’s not likely that you can ever separate them so that you only end up with cocoons, but I suspect that you could end up with a mix that makes it a lot easier to remove them by hand.

Something else you might want to consider is attempting to get your cocoons to hatch out in the vermicompost before you start using it. In the case of wet vermicompost, it is always a good idea to give it some time to air dry in a well-ventilated tub, or even in a heavy duty cardboard box (as suggested in “Worms Eat My Garbage”) – this can be a good time to see if you can encourage hatching to take place, and just generally round up all the babies left in the material. To accomplish this, you might try putting some cantaloupe or melon pieces on top of the compost, and simply cover it with some burlap (newsprint etc). Over time you should start to see lots of little guys congregating under the food materials. By the time your compost is nice and dry, hopefully you will end up being able to scoop up most of your remaining wigglers quite easily before you start using the material.

Anyway – just some thoughts on my end. Will be interested to see what others have to say!

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    • LARRY D.
    • September 9, 2010

    If you don’t want to wait for the worms to hatch out as Bentley has covered.I will cover what the screen sizes can do.And also it should be noted that what you are screening,should have time to dry enough to be able to work with.Which times vary greatly.
    1/4″hardware cloth will separate the big stuff from the vermicompost.It will not save any cocoons.But the vc is ready to be used where ever you wish.
    1/8″ screen will save some or most cocoons,especially if you screen more than once.But bear in mind that different EF’s have different size adults too.And the larger cocoons will not usually go through,but the smaller ones can and will.Through three screenings i still notice a few cocoons.
    1/16″screen will virtually save all the cocoons,but it also gives you mostly straight worm castings.Which a lot of people only use straight castings to make worm tea(compost tea).But i understand that vermicompost,instead of straight castings(vermicast)is better to use in a solid form on plants.(i make dirty tea,by just adding water and stirring,then just pour at the base of the plant.Without using an aerated brew cycle for 24 hours).
    Hope this helps.
    And one note:Perionyx excavatus cocoons could probably go through even 1/16″screen in small amounts.

    • LARRY D.
    • September 9, 2010

    I forgot to note that a full scale larger flowthrough is supposed to let the cocoons hatch out before they reach the bottom.I just haven’t been able to keep mine fed to reach the ultimate depth.Not only does it reduce the volume from coming out the bottom,but you can watch the level drop from the worms reducing the size of the matter when they work their magic(chow down).

    • Barb V.
    • September 9, 2010

    Harvesting cocoons has been the subject of several threads in the vermicoposting section of garden web. One I recall had to do with putting compost in water and cocoons float to the top. Another method uses layer of burlap on surface of worm bin/pit. The worms are attracted to this moist environment and lay cocoons.
    I also recall from one of Mark’s videos where he put melons in ‘finished’ VC to attract hatchlings. Since my climate allows for in-ground worm pits, I use the ‘here & there’ method Bentley describes.

    • John Duffy
    • September 10, 2010

    I’ve only been vermicomposting for 9 months but, I remember my excitement when I harvested my first batch of VC. I had baby worms and cocoons in such numbers that it staggered my imagination…I spent about 4 hours meticulously harvesting each & every one with great enthusiasm!…Then reality kind of kicked-in… These little buggers are so prolific that, if I miss a few babies or cocoons while harvesting my VC, Mother Nature will deal with them on her own terms…In other words, they’ll either hatch & reproduce or end up feeding the next worm bin.
    It’s all good! Don’t sweat the details…Enjoy the journey!
    Oh Mark…Congratulations on your accomplishment of keeping a TON of waste out of the landfill. That’s something to be proud of!
    Looking forward to more of your posts.
    Bentley, as always thank you for such a great website and all your advice.Vermicomposting is truly a worthwhile passion and the more people we can get involved with it, we CAN help to make the world a better place for everyone!

    • Matt
    • September 13, 2010

    I am seeing more and more worm sellers selling cocoons and shipping. There must be an easier way of seperating than picking out 1000 cocoons than hand sorting, not alone counting 😉

    I am so tempted to order just the cocoons, I would think it makes packaging and the weight of shipping less. If the majority of the cocoons hatch, I am sure there would be more worms than I would get if I ordered a pound of EFs

    I have to try the water and floating cocoons to see how that works in the future.

    Happy Worming

    • Kator
    • September 14, 2010

    Hey Matt: I’m also trying to determine the best method of harvesting cocoons. From what I’ve read, harvesters that sell quantities of cocoons have very large operations, part of which involves screening for cocoons to sell. Their recovery percentages are not high (±30%), but due to the quantity of compost processed, they recover a sufficient quota of product to sell. The remainder is recycled in fresh pans.

    My primary objective is to collect a sufficient number of capsules, over a period of several months, to generate a new system in a slightly different bedding and feed environment from source bins. I’ve concluded that screening and manual sorting is the best method. It’s labour intensive but, possibly, the most productive.

    Please let us know how you make out with floating cocoons recovery. Sounds like a greart experiment. Good luck 🙂

    • Bentley
    • September 14, 2010

    LARRY – Thanks for sharing all that!
    BARB – That is something I’ve wondered about (along with some sort of spinning water separation), but the limitation in my mind is the fact that you are turning your beautiful castings into mud as a result. I guess it comes down to importance (are cocoons more important than good castings?). Burlap is a cool idea – I bet there would be loads deposited in that.
    JOHN – I like your philosophy. I’ve spent WAY TOO MANY HOURS engaged in tasks like that (which CAN certainly be relaxing and fun – don’t get me wrong), so I am much more interested in faster methods (if they exist) or simply being laid back about it.
    MATT – Good point. I’d be interested to learn how they are effectively harvesting them. I know someone came up with a technique/machine for harvesting regular earthworm cocoons a number of years ago – perhaps there is now some equipment commercially available and I’m simply in the dark as per usual!
    KATOR – Thanks for sharing that. Makes sense! I will definitely be interested to learn how your own experimentation turns out!

    • Cyndi Warren
    • September 25, 2010

    I have agonized about saving every baby worm and cocoon while harvesting, only to miss some I found later in the ziplock full of harvested compost that died trying to get out. I HATE that! Maybe I could leave harvested compost outside on a tarp for a few days and (as someone here said) let Mother Nature work it out. At least they’d have a chance that way.

    • john
    • April 17, 2011

    this is my first batch of compost from my red wigglers i,v just made a screen harvester that seems to be working good it has seperated the compost into fine,medium,and course with my worms in the course i,v yet to see any cacoons im going to hand sort the medium compost to see if i can find any cacoons i,m going to try screening the medium again to see if i come up with any cacoons or hide out worms I also agree with JOHN DUFFY about the feeling you get with your first harvest I started out with 3000 red worms last summer and after my harvest I must have about 90000 now

    • Katrina
    • April 23, 2012

    I have always separated out as many of my worms as possible by picking and screening, throwing the worms in a fresh composting bin and putting the finished compost in an empty bin. I then moisten some bread and lay it out on top of the finished bin. This seems to work very nicely in moving any missed worms under the bread, where I can easily scoop them out. I do this for about 6 weeks before I use the finished compost-This way, I’m sure I’ve gotten the majority of the worms that were cocoons when I separated out.

    • Leslie
    • May 13, 2013

    I have gone bug-eyed and finger cramps getting my cocoons out of my castings. I have purchased an 1/8″ hardware cloth to help and I am going to build a rotary screen like I have with 1/4″ mesh. I built a worm hotel instead of a factory that I keep in my garage. The hotel is five stories high with 1/4″ hardware cloth stapled on the bottom of each floor. My floors are made of 1X6″ cedar milled on one side and rough on the other (outer side). My walls are glued and nailed together and have a 1X2″ cedar strip for support in each corner. The cedar strip is as long as the walls are wide but off set by 1″ so I have a little foot on each wall that connects into the top of the floor below for stability. One piece of newspaper on the bottom of each floor to hold the bedding and food. The worms eat through the newspaper when they are ready to move up. I built a stand (basement) under the floors and placed an open plastic bin to catch moisture. I have not caught any moisture in the bin and have harvested the pooh 3 times. I run everything through the 1/4″ mesh rotary screen and return the oversize back into the floors with a fresh piece of newspaper. Last harvest 8# of castings little fuss or mess.

    • Tommy D
    • April 26, 2014

    I am not worried about loosing eggs as introducing a none native species into my area.
    Im just starting but plan on building a sifting and floating system. I would think once you have sifted down to 1/8 you could float the eggs and strain out the castings. Then I plan on killing any remaining worms (I know some might think this bad but I think dumping out worms not native to your area is unconscionable.)

  1. For my secondary screen, I use an office paper tray made from a diamond shaped screen material thats about 1/8″ on the long side. This catches almost every single cocoon.
    As for the babies, once I’m done sifting I set aside the sifted castings in a tall kitchen waste basket and leave it for the wisps to grow into something I can see and sift for…
    With red wigglers I wait 6 weeks and ANC I wait 3-4 weeks.

    I’ve been trying to find this diamond shaped screen in a roll so I can make a better sifter for this size, but the office tray works for now! 🙂
    Any longer and you might get a new set of cocoons to deal with.

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