Spongy, Muddy Vermicompost?

Here is a question from Andre:

After 5 months on vermicomposting I decided to harvest some
booty. I made a bucket/screen getup with 1/4 holes. After running
about 1/4 of the castings through it I ended up with about a cup full
of spongy amorphous castings like the consistency of drying mud. The
compost is coming out of 20gal plastic bins that are drilled full of
1/8 inch holes. Any advice on how to get it dry and free of the tiny
baby worms?

Great question, Andre – and likely a very similar situation as that faced by countless other enclosed-plastic-bin vermicomposters!

I hate to say it, but unfortunately there is no getting around the fact that it’s more difficult to produce really nice worm compost in an enclosed plastic bin system – even with LOTS of air holes drilled in the sides and lids (even with fancy vents). Plastic is simply TOO effective when it comes to retaining moisture!

The good news is that you have a number of options as far as remedying this situation goes. For starters, you might think about switching over to a completely (or at least partially) lidless approach. It is amazing how much of a difference the simple act of removing your bin lid can make in terms of reducing the moisture in the bin, speeding up the vermicomposting process, and even helping to create a much nicer end product!

If you don’t want to leave your lid off all the time, you might try simply doing so on days (and during daylight hours) when you happen to be around – this alone could have a pretty significant impact on the system. Whatever your approach (lidless or semi-lidless) I DO recommend that you always maintain a nice thick layer of bedding in the bin (as much as the bin will hold). This way you will help to keep light from bothering the worms (and influencing their level of activity in the bin), you help to prevent the bin from drying out too quickly, and you help to keep your system “off the radar” of various annoying critters (like gnats and fruit flies).

Assuming you have no interest in using a lidless bin…

Your other option involves some sort of vermicompost remediation before attempting to screen and/or use the material.
This does not need to be a complicated process at all! Simply dumping the contents of your bin out onto some sheets of corrugated cardboard (or a larger bin with layers of cardboard at the bottom), then letting everything sit for awhile should work wonders.

Don’t forget to regularly break-up and mix the materials (a small hand fork should work well) during the drying process though! I kid you not, when I say that there must be potential real world building applications for the use of vermicompost “cement”! This is incredibly hard stuff if left alone to dry.

The drying stage has a number of great benefits, apart from improving the potential for screening and using the material. For one thing, it provides the compost with the time to fully stabilize in a nice, aerobic environment – very important for the creation of high quality vermicompost. Anyone who has dumped out the contents of a mature plastic worm bin will undoubtedly agree that the aroma that wafts up 9 times out of 10 is anything but aerobic!

This drying period can also provide you with the opportunity to extract the zillions of baby worms (including those still in cocoons) usually remaining in the material! One approach that can work involves adding some watermelon, cantaloupe, or really any moist fruit waste to the top (ideally covered up with bedding materials) then waiting for the little wigglers to start congregating underneath and scooping them up when they do. Given enough time, even the the most recently deposited cocoons should release their weeny, wiggling cargo.

Anyway, I hope this helps, Andre!

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    • LARRY D.
    • August 5, 2010

    Also one advantage of no lid is the lack of moisture on the walls.The worms don’t like the feel(like a driveway)and stay comfy in the moisture they call home.If you see the moisture on the walls you see worms.In three months i have not seen one worm climbing my walls.And i’m talking 4’x8’or 24′ of wall they could climb on.Even my small bins i don’t have worms climbing.
    If i had them leaving.Something bad would be going on down below!

    • Steve K
    • August 5, 2010

    I hope to do my first harvest in a couple of months. This detailed info is super helpful (as usual), esp. the bit about drying on cardboard.

    • Anna
    • August 5, 2010

    Speaking of moisture in finished vermicompost, is there an ideal amount? Is there a point at which it is so dry the beneficial microbes in the vermicompost are killed off?

    • Bentley
    • August 6, 2010

    Great point Larry! This is why I will often recommend (with enclosed plastic bins) people keeping a really thick layer of dry bedding up top – this tends to dry out the walls and lid making this zone a bit more unfriendly for the worms.
    STEVE – glad you found in helpful! The cardboard probably isn’t vitally important (and likely the BEST solution would actually be some sort of fine mesh platform raised up off the ground) but it should definitely help speed things up.
    ANNA – good question. It is tough to give a really specific answer, but what I would say in general is that, ideally, the material should not be so moist as to ball up really easily (grab a handful and let it drop back down – if it all sticks together it is more than likely too wet still), but not so dry as to be powdery. It should feel slightly moist, but not leave your hand wet (or muddy) at all.
    Make sense?

    • Christian
    • August 9, 2010

    This is the post that I’ve been waiting for. It seems like such a simple solution to the problem, but I guess that my paranoia lies in letting fungus gnats come back after they took over my kitchen area for a few weeks.

    I thought that letting the worms really work through the food (because I was adding too much of it) would help mitigate the moisture problem in my plastic bin, but all it did was make the end-product richer and darker with castings, but not actually drier or any easier to work with.

    I was starting to wonder if my conditions had become acidic. My poor worms are probably starving because I’ve been feeding them so sparingly in hopes that it would dry the bin out. I’ll keep the lid off for a few days and just put some shredded newspaper on the top.

    A lot of shredded newspaper, I guess!

    Thanks Bentley! Genius as always!

    • Jean Kruse
    • August 19, 2010

    I’ve found that when you have vc that is finished or almost finished but is too wet to process, just dumping it all in a cardboard box and closing the lid for a few weeks works very well. And when the vc is done you rip up the damp box for your next batch. This method comes from Heather in Dallas, Texas.

    • Bentley
    • August 19, 2010

    Great suggestion, Jean
    Thanks for sharing (thanks also to Heather).
    Mary Appelhof mentions something along these lines in Worms Eat My Garbage as well, so it definitely sounds like a solid method! Using a box vs dumping everything on sheets of cardboard is also a nice way to contain everything and ensure that it won’t dry out “too fast”.

    • Angel
    • September 14, 2010

    Hi Bentley, I got a Worm Inn back in June after using a Rubbermaid system since April. My vermicompost was pretty developed by the time I switched over to the Worm Inn, though, like this post addresses – very wet and mushy, so I didn’t harvest any of it.

    Since going to the Worm Inn, it is definitely in better shape. No more sludge…but with the new open air system, the worms are eating through their food pretty quickly, and I thought it was about time to harvest some compost.

    When I started the sorting process tonight, though, I had second thoughts. I have lots of little pieces of cardboard that are still in the compost, even in the bottom most layer. And when I started removing compost from the bottom, there were plenty of worms in it. I watched your Youtube video when you harvested your worm inn, and you mentioned that very few worms were in your bottom layer.

    I have a picture here of what my bottom layer looks like:


    Most of it looks good to me – it’s just the presence of the worms (TONS of babies and cocoons…I tried separating them all out, and after an hour, I got about 1/4 cup of compost free of worms and cocoons) and the many pieces of cardboard that I’m not sure about. Do I need to pick out the pieces of cardboard and put them back in to be processed, or will they be okay to use on plants? I guess I was imagining the harvested compost looking just like dirt, with nothing else in it, but maybe the eggshell bits, cardboard, etc is supposed to be there? Thanks so much for all your help!

    • Angel
    • September 14, 2010

    Oops, the picture attachment didn’t work. Here it is again: http://www.facebook.com/photo.php?pid=31654217&l=53aef923ef&id=187701110

    • Angel
    • September 14, 2010

    Not sure why my picture URL didn’t show up. Here it is again:


    • Bentley
    • September 14, 2010

    I’m getting “content not found” when I follow your link, Angel

    • Angel
    • September 14, 2010

    Hmm, not sure what’s going on with sharing the link here, but I posted a picture on the Red Worm Composting Facebook wall. Let me know if you have trouble finding it. Thanks!

    • Sarah
    • September 25, 2010

    one effective way to combat moisture is by the use of
    desiccants like silica gel These are the same small
    sachets you find in packaging of various products like
    abspbing the moisture in its surrounding area For most
    moisture challenges does the job With small sachets cost less
    than a dollar, it truly is a cost effective way of protection
    from mosisture There is a lot more information and an order from on our website at http://www.SilicaGel .net

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