Preparation for Winter Worm Composting

Preparing the winter worm bin

For the last little while I have been adding all my food scraps to my normal backyard composter, rather than my outdoor worm bin (pictured above), although as mentioned yesterday, I’ve now converted the composter into a worm bin too.

This year I am once again going to give winter composting ‘the ol’ college try’, to essentially see if it’s possible to vermicompost all year long up here in Ontario (Canada). My last attempt was documented on the EcoSherpa blog. You can find all the pertinent links (and pictures) on our EcoSherpa Squidoo Lens (photo links are part way down the page, followed by links to the blog posts).

[UPDATE 2018: EcoSherpa (and Squidoo) are no longer online so the links have been removed]

I will be providing full coverage on Red Worm Composting (and another soon-to-be-revealed site) this time around, so all my faithful vermi-friends (readers, not worms) will be able to follow along!

So why exactly am I not adding any more waste materials to my outdoor bin?

Basically I need to make room in the bin so I can 1) More easily add insulating layers of cardboard against the inside walls of the bin, and 2) Free up lots of space for fresh materials, which will be vitally important in order to generate a decent amount of microbial heat.

It’s been amazing watching just how quickly the level of the material in the bin goes down now that I’m no longer adding anything! Yet another reminder of just how awesome composting worms are when it comes to processing wastes.

This fall I will be collecting lots and lots of fallen leaves (may even ‘steal’ some bags from my neighbours’ curbside collections! 😆 ) – this will be very important for insulation and helping to keep the microbial fires a’ burnin! I’m also hoping to secure a supply of manure as well, since we’ll definitely need nitrogen if we expect to create a decent amount of heat.

Like last year, I will be insulating the outside of the bin. I’m thinking about using a thick layer of styrofoam insulation this time – should be better than the homemade system I created last year, and has the advantage of being easily re-usable next year. I will also once again put a tarp over top to help block wind and keep out precipitation.

I will also likely test out a new strategy this year for making sure the contents of the bin don’t freeze during the coldest months. It is actually a technique Mary Appelhoff (vermicomposting legend, who sadly passed away a couple years ago) used to keep her outdoor bins active during Michigan winters. What she did was put a bird bath heater inside a bottle of water and buried it in the centre of the bin. This ensured that the water in the bottle was always above zero, thus helping to keep the surround material above zero as well. I could of course go completely overboard and install soil heating cables, but I think that would be a tad excessive (not to mention expensive as far as my utility bill goes!).

Anyway, it should be a lot of fun! My neighbours will once again think I’m even more of a weirdo than they already do, and I think I can definitely succeed this time!!

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    • Kami
    • September 30, 2007

    Did you make your own outdoor bin? It is lovely!

    • Bentley
    • October 1, 2007

    Thanks Kami,
    I did in fact make it (last summer). I am the furthest thing from a ‘handy man’ type so I was definitely impressed that I was able to build it without having it fall apart on me. haha

    • Alison
    • October 1, 2007

    Great stuff Bentley, I will be really keen to hear how it goes.

    • Alison
    • November 13, 2007

    Hi Bentley, how is your outdoor bin going now? Has your winter started? Do you have any photos of your bin as you finished preparing it for winter?

    • Bentley
    • November 13, 2007

    Hi Alison,
    It has been going well. The outer wall is now constructed. All I have to do is fill it with insulation. Will be putting together a video (containing lots of photos) all about it soon.


  1. I live in Denmark and although it is nowhere near as cold as some parts of Canada and the US, Temps can go down to -20 C, I thought about using a low wattage infra red bulb, the same kind that you use for young poultry to keep the temp. in the bin up on the coldest nights. has anybody tried this?


    • Bentley
    • November 19, 2007

    Hi Nick,
    Your winter temps actually sound quite similar to ours. I’m in southern Ontario, so certainly warmer than some regions in Canada.
    I have not tried any sort of bulb myself, but I imagine it would provide a decent amount of warmth – the only question is how much your utility bill might be!

    Anyway, I’m almost finished insulating my outdoor bin – as mentioned, a video will be on the way shortly!


    • J
    • November 20, 2007

    Hey Bentley!
    I’m right with you trying to make a a comfy outdoor home over the winter. Thanks for the bird bath heater tip, I believe this will help me and my wormy pals feel much better.

    • Bentley
    • November 20, 2007

    Great, J!
    We’ll have to compare notes once the snow really starts to fly! 🙂



    • Bentley
    • December 19, 2007

    Hi again, Graham!
    Those are good questions, especially considering how much I harp about keeping bin conditions aerobic!

    For starters, I aim to keep temperatures fairly low (in comparison to summer vermicomposting that is). If I can keep temps in the bin 10-15C (50-59F) all winter I will be thrilled!!

    So far everything has been proceeding beautifully. We’ve had some serious winter weather already yet conditions in the bin are perfect.

    Anyway – I got sidetracked there – haha! Lower temperatures means lower rates of respiration in the bin (thus less oxygen consumption). Obviously we need SOME O2 consumption however since that is what generates the warmth in the bin!
    I try to open up the bin at least every other day (although sometimes it goes longer), so that helps. Also, the bin itself is not sealed like a plastic tub – it is made of slats of wood with spaces in between. I imagine there is quite a lot of air that gets in from the top. As such, my compost does not smell (other than a nice earthy odour)

    BTW, you can read about my winter composting experiences on my compost guy blog:

    The most recent posts will appear first.


    • Jonathan
    • September 1, 2009

    Have you considered instead of using a tarp you could try building a “solar heat collector” and using that as the cover to the bin? Something along the lines of a box slightly larger than you bin painted black on the inside (possibly even filled with aluminum cans painted black) covered with a layer of glass or plexi glass. This will collect heat from the sun and the air layer will help to trap it. Got the idea from a solar water heater.

    • Kristen
    • January 19, 2010

    Bentley, id love to hear what you think of jonathans solar cover idea , i am living where there is no electricity and keeping worms alive during the winter(in N.Y. state) is an issue!

    • Bentley
    • January 19, 2010

    Hi Kristen,
    This is an ancient post, but THANKS for commenting here. I totally forgot about Jonathan’s comment (sorry Jonathan!). Interestingly enough, some of my most recently posts have centered around the topic of warming up my current “Winter Worm Windrow”. Jonathan’s idea certainly sounds like a cool approach. It might be a little involved for me to do something like that in this situation, but what I HAVE been thinking about is placing clear plastic over top of the black tarp that already sits on the bed – this way I should be able to hold some of the solar-generated heat in a little longer.

    • Jonathan
    • January 20, 2010

    glad I could help

    • cecil pearson
    • January 22, 2014

    I’m in north eastern North Carolina and I keep my totes of worms in a closed room off the side of my open garage. Because my water pump is located in this room I keep a 250 watt light bulb burning all the time. The temp stays around 55 to 60 degees from October until March/April. Even with the current temps of 10 to 17 it maintains at least 45 degrees with the help of a heat lamp on the cold nights………………………

    • Paul Chalmus
    • August 23, 2014

    Hi, Bentley….I just stumbled across these old comments about you rigging up your compost container to secure your worms from the winter weather. The articles are 2010 it is 2014 now….How did things turn out? I had lost all of my worms during the winter. By the way, What’s a spammer?

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