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Winter Composting

Insulated Winter Composting Bin

Aside from having a specific ‘Winter Composting’ category on the blog, I decided it might be helpful to create a winter composting resource page so people can A) learn more about winter composting in general, and B) access all the pertinent blog posts I’ve written (here and elsewhere), along with other useful tidbits (videos, photos etc). I’m going to keep things relatively simple for now, but will definitely continue to build this page over time.

What Is Winter Composting and Why Should You Do It?

Let’s start by defining the term ‘winter composting’. Obviously we are talking about ‘composting in the winter’ here, but I think it’s important to point out that when I say ‘winter’, I’m referring to the real deal – the often-harsh, snowy, freezing winters encountered in Canada and the northern states (along with many other regions of the world). To be totally honest, my location in Southern Ontario (Canada) is somewhat tame in comparison to many regions of the ‘Great White North’ (and even Northern USA), but I have little doubt that outdoor winter composting can take place in much colder regions as well, with a little bit of extra effort.

Now that you know what I’m referring to when I talking about ‘winter composting’, you may still be wondering WHY?!?
I imagine the very notion of winter composting must seem a little extreme, or ridiculous…or perhaps even extremely ridiculous to some people (my neighbours, for example)!

After all, why on earth would anyone want to trek outside in sub-zero weather to add kitchen scraps to their compost bin when their gardens are frozen solid and there are other indoor methods, such as bokashi or vermicomposting, that can be employed to deal with waste materials during the long winter months.

Good question!

Here are some possible reasons for keeping an outdoor compost bin active all winter long:

These are just a few of the possible reasons for giving winter composting a try!

Basic Requirements for Winter Composting

Heat Source
In order to compost successfuly all winter long you need to make sure that your system stays microbially active. A frozen heap, or even one with temperatures just above the freezing mark won’t do you much good. Keeping a system warm and microbially active will require the presence of an external heat source or enough material (‘critical mass’) – with a well balanced C:N ratio ( somewhere between 20:1 and 40:1 will work best) – to support microbial heating. The critical mass for thermophilic composting is generally in the range of 1 cubic yard – so you will definitely want to use a system that has a volume of at least that much (the colder your region, the bigger you’ll likely want to make your system).

Unless you are creating massive winter composting heaps (a lot bigger than 1 cubic yard), you will likely also need to insulate your system somehow. An excellent low-tech approach would be to simply stack up straw bales around the outside of your bin. In fact, you could make an excellent winter system by simply stacking straw bales (to create the walls), then filling it with your balanced mixture of waste materials.

To create my current insulation system I first lined the inside of my bin with multiple layers of corrugated cardboard, then built an outer wall around my bin, thereby creating a space I could stuff full of insulation (in my case, second-hand home insulation). I then added some additional layers of cardboard between the outer wall and the insulation layer.

In areas where heavy snowfall occurs, snow can obviously be used as a great supplemental layer of insulation – I have big heaps of snow adjacent to 3 of the 4 faces of my bin. Another great naturally occurring source of insulation is the earth itself. Digging a compost pit in the ground, or better yet into the side of a hill can be an easy (and effective) strategy.

Apart from having insulation around the outside of your bin, it will also help to maintain a thick layer of bedding over top of your composting mass. Loose straw and fall leaves are very well suited for this task, but there are plenty of other possibilities as well.

To keep your system chugging along all winter, it will certainly help to continually add fresh waste materials. I recommend keeping a bucket (or larger container) for all your kitchen scraps to ensure that you are adding a decent amount each time you make a trip to the bin. You may even want to seek out external waste sources just to make sure you have enough. Local coffee shops (for coffee grounds), grocery stores (for waste produce) or stables (for manure) are just a few possibilities.

Winter Composting Posts from 2007/2008 (Compost Guy Blog) (in chronological order)

Winter Composting Extravaganza II
Oh, The Weather Outside is Frightful!
New Years Composting
Ask and Ye Shall Receive
Windy, Warm…Now Wintry!
The Real Challenge Begins!
Wacky Weather Continues
More Snow, More Cold – What Else is New?
Winter Composting Wrap-Up


If you have Flash installed, you may want to watch the full (longer + high resolution) version on the Red Worm Composting website. Access the page >>HERE<< (again, remember you will be leaving this site)

Winter Composting Posts from 2006/2007 (EcoSherpa Blog)

Winter Composting Extravaganza
Composter’s Log – Stardate 60352.8
Composter’s Log: Stardate 60376.9 – RED ALERT!!
Composter’s Log: Stardate 60393.6 – Winter Has Arrived
Composter’s Log: Stardate 60429.3 – Unusual Life Forms
Composter’s Log: Stardate 60492.2 – ‘Oh Winter, Where Art Thou?’
Composter’s Log – The Iceman Cameth
Composter’s Log – Dontchu Know I’m Loco?!
Composter’s Log: Letting Sleeping Mice Lie
Composter’s Log – Back In Business!


Read the comments left by other users below, or:

Get your own gravatar by visiting Lydia
#1. August 1st, 2008, at 4:26 PM.

This looks awesome. We are looking for a way to deal with dog waste. We already compost during the summer but it would be nice to do year round.

Question: Do you add to the compost pile during the winter? I’m sure you don’t want a heat loss. How do you handle this?

Get your own gravatar by visiting Compost Guy
#2. August 2nd, 2008, at 4:54 PM.

Hi Lydia,
I definitely need to add to the compost box during the winter in order to maintain warmth. You are right – heat is lost when the bin is opened, but it’s a trade-off. By adding organic waste I help to generate more heat. If I stopped adding anything, it would continue to cool down and potentially freeze.


Get your own gravatar by visiting Kris
#3. October 15th, 2008, at 12:28 AM.

Could you keep a bin in the garage all winter? How cold is too cold? Do I need a special bin or just a big rubbermaid tub and a pitch fork?

Get your own gravatar by visiting Robert
#4. November 24th, 2008, at 8:36 AM.

While creating a substainable condition, such as heat, is it ok to mix
around the pile or bin in the winter, fear of conditions heating up too much?

Get your own gravatar by visiting donald russ
#5. April 22nd, 2009, at 4:24 PM.

How is ventilation provided for the insulated bin?


Get your own gravatar by visiting Nikki
#6. January 2nd, 2010, at 10:03 PM.

I just received a compost bin over the Christmas holiday…is it ok to start adding kitchen scraps to it now to later thaw in the spring? First sign of spring I will be adding straw and perhaps a bag of compost accelerator. Is this ok?

Get your own gravatar by visiting Ken
#7. January 20th, 2010, at 2:23 PM.

I have found it extremely beneficial to employ the same methods year round. A simple plastic tarp traps both heat and moisture and creates an environment where high temps often exist all the way to the surface. This makes it much simpler and effective to kill weed seeds not to mention that it dramatically reduces labor to turn or water.
I have a local furniture store that supplies me with large heavy bubble wrap sheets (8′ X 8′). As long as I only cover the top two thirds of the pile and leave the bottom third open, the escaping heat around the perimeter of the cover draws ample air into the pile to keep things cooking for a long time. I have found that this cover allows my pile to stay hot longer and therefore finish out much faster. Uncovered, my pile would hit the cool down period too soon, even though the product wasn’t very “mature”.

Get your own gravatar by visiting Marilyn Cunningham
#8. November 24th, 2010, at 1:39 PM.

We started a small compost box this past summer. It’s small because we have a small household. We were reasonably successful, but now winter has arrived it’s stopped “working”.
I’m considering adding kitchen scraps to the pile throughout the winter even though it won’t do anything until spring. What problems could we have with this method?

Get your own gravatar by visiting David Stuettgen
#9. December 13th, 2010, at 4:11 AM.

Moved my compost bin into garage, but haven’t started yet. Thought about ins. w/ straw slabs and cladding w/ cdboard. Main concern is I don’t have available green matter. I have a leaf stk pile that’s frozen and that is it. Would brewers waste help any? I know this alone will not help, but just as a small addition to the mix.

Get your own gravatar by visiting Sampson
#10. January 13th, 2011, at 12:13 AM.

I appreciate the advice and even though I can understand why you said it seems ridiculous to work on compost in the winter I have a perfectly good reason to back you up.

I’m doing my senior project next semester for high school and I’m making ethanol for my project.

Ethanol needs compost, and I have to start now – in the winter! =D

Get your own gravatar by visiting Kim Israel
#11. January 19th, 2011, at 3:57 PM.

Hi, I am new to indoor vermicomposting and I have two questions. #! my worms are at the top of my indoor bin and not really in the layers. I followed exact instructions on allowing my readied bin sit for two weeks, what is going on that my guys aren’t in the bedding? My second question is regarding my outdoor compost. Now that I am using worms, can I use worms in an outdoor composter where I use an activator?
Thanks so much for your help!
Kim Israel
Barberton, Ohio

Get your own gravatar by visiting Matt
#12. January 2nd, 2012, at 1:34 AM.

Thanks for your help in getting this rolling. Track my progress here:

In the Twin Cities of Minnesota, attempting to compost through the winter with a critical mass. The temperatures haven’t really dropped yet … which is sad seeing that is is November!

Check in and see how it goes!

Get your own gravatar by visiting Simple Guy
#13. December 2nd, 2012, at 3:12 AM.

I can’t get a compost pile going in the Summer and I’ve got one of the barrells that supposively makes it easy. lol
Is there an accelerant I need to add?

Trackback Mention from
#14. December 30th, 2012, at 12:43 AM.

Where should I put my worms? | This page is on composting but it might give you some ideas. [...]

Get your own gravatar by visiting Jim
#15. January 25th, 2013, at 8:46 AM.

I’m in SE Michigan and have been composting actively for several years. After two rather mild winters (and a respite of several days the other week that were quite warm) we’re back to traditionally cold weather. I use a small setup, as I am alone here, so a civic-type recycling container in a covered outdoor area is my choice, and in Winter, also large planting containers.
In a container, runoff leaching is not a concern, but I prefer not to add anything with significant liquid due to that encouraging further freezing. Until just the other week, in January, I had not had the ‘big block of ice’ and blame too much moisture in part there. Will be trying to add more coffee grounds soon (though the mix already had a lot) as I’ve seen their melting effect upon snow before. Adding hot water is not the answer here!
I have a strong impression that the very cold weather enhances the physical breakdown of the compost materials–that’s what happens to outdoor natural materials here anyway–so that in a matter of weeks when things thaw out, the fracturing and softening and other effects of the freezing will help to speed up any plant fiber decomposition, and that will be accelerated by digging and moving the compost while still partly frozen (but not immobile, as it is now).

Get your own gravatar by visiting Jim
#16. January 25th, 2013, at 8:52 AM.

Oh, and I never have the cubic yard that’s often suggested, but in general from about March or April through November, the smaller container I use (made of fiberglass or heavy plastic) works well and the compost seems to be rapid. And for up to three months (or more), the compost just doesn’t visibly do much.

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