We know composting is good for the garden and the environment, but did you know you can save food scraps for composting all year-round—even in a cold climate? Composting in winter is simple and takes just minutes each week. I’ll walk you through the method I use from late fall to early spring.
If you’re new to composting, this explains (in simple terms) why it’s smart and essential: Composting 101: Slow & Fast Methods.
A Smart, Time-Saving Winter Composting Method
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Compost is a great and beautiful thing and while I treasure it for the garden, I don’t wish to make composting my life’s work.
I live in a cold climate (Ontario, Canada) and have always kept my food scraps for composting all year-round.
Winters here are long so we would miss out on a lot of good compost if we didn’t keep the bin going in the colder months.
I’ll show you how I keep it really simple, fast, and efficient, without any stinky mess.
Related: The Most Important Fall Garden Tasks.
Winter composting is like summer composting but in slow motion.
In the coldest weather, the process simply stalls and the food scraps freeze.
When temperatures rise above freezing, the process resumes. If your winter is long like mine, the volume of food scraps is considerable and definitely worth saving.
If you are new to composting, I’ve listed the basics as well (below).
Winter Composting Goals
- Save kitchen waste year-round, diverting it from landfill.
- Avoid fruit flies in the kitchen.
- Avoid attracting wild animals.
- Minimum effort.
1. Set Up Winter Compost Bin with Lid
With this method, you set up a bin close to the house where it’s convenient and you won’t need to shovel a path to get to it in the middle of January.
Choose a bin with a lid that is animal-proof if this is a concern. If this was for warm weather, we would want ventilation holes. I have not found this necessary for winter composting.
A Galvanized Trash Can
- I use a galvanized trash can with a tight-fitting lid: here’s the galvanized steel one I like at Amazon: Garbage Can (20 Gallon).
- Unless you have bears or super-determined raccoons, this should keep prying hands away. Plus, with a locking lid, you can roll the can to stir the contents.
B Compost Tumbler
- If you have room, a drum compost bin is another good option. I also have a Mantis one like this one on Amazon.
C Food Grade 5-Gallon Bucket
- A five-gallon food grade bucket (with lid) is also a good option, especially if you expect lower volumes of food waste.
- Add a foot (12″) of browns (carbon-rich goodies including straw and/or newsprint and/or dead leaves) to the bottom of the trash can.
- Keep a giant bag of extra browns nearby to add to the bin during the winter. For every pound of greens (kitchen waste), add a bunch more of browns.
I have a full explanation of greens and browns here.
- Keep the bin somewhere where you can easily access it during snowy weather (without having to shovel a path, if possible).
- Keep the lid on and, if possible, choose a location where wild animals cannot access it.
2. Collect Kitchen Waste
- The greens (nitrogen-rich goodies) include scraps from fruits and vegetables, egg shells, coffee grounds, tea bags (no paper or staples, though). No processed foods, meat, or dairy.
3. Freeze The Scraps
If you don’t have time to add scraps to your bin daily, freezing is another option.
I do this step (all year-round) because I don’t like the stink of keeping a scrap bin in the kitchen and it prevents fruit flies.
- Super Lazy Method: Keep one heavy-duty freezer bag dedicated to kitchen scraps (greens) in your freezer.
- Mildly Lazy Method: Chop or blend your scraps into small bits and pieces. Then place in a heavy duty freezer bag in your freezer.
Small pieces break down faster.
4. Add Frozen Scraps To Winter Bin
- When the freezer bag is full, add the contents to your winter compost bin.
- The scraps will freeze and thaw, depending on the temperatures. Decomposition continues during warm spells.
- Remember to add more browns to bin each time you add greens. A warm spell without enough browns will cause the materials to ferment. You don’t want that.
- Wash out the freezer bag and reuse it over and over again.
- During thaws, when temperatures stay above zero for a few days, check the bin. You can roll it or use a shovel to combine the greens and browns.
If we get a really warm spell, I keep the lid off until freezing temperatures return.
6. Spring Time
- In spring, as soon as weather permits, pour the contents of the winter bin into your regular compost bin or pile. Add more browns if needed. The composting materials should be slightly moist (naturally) due to the moisture in the green materials. If it seems dry, you can water when turning the pile.
And that’s it! That’s winter composting.
It’s super easy when the weather stays consistently cold and everything freezes. It’s just the warm spells where you need to check on it.
With many months of winter, that’s a lot of food scraps!
Composting is a process where micro- and macro-organisms (bacteria, worms, and more) decompose natural materials (including leaves, fruits, and vegetables) into earthy matter. This earthy matter is compost and we add it to our garden beds to enrich the plants.
You can read a thorough description of the process here or keep reading (below) for the quick overview.
What can we add to the compost pile?
To keep it simple, we divide the materials into two camps.
|1. Carbon Suppliers
Mostly dry, porous materials
aka ‘the browns‘
|2. Nitrogen Suppliers
Fresh, moist materials
aka ‘the greens‘
Ratios matter. The research shows that a carbon:nitrogen ratio of 30:1 is optimum. University Extension offices have excellent research online if you would like to learn more. But that can be hard to translate into the amounts in the actual greens and browns you have on hand.
The simplest way I have found (with good results) is to do this:
For every pound of green materials (nitrogen suppliers), add some browns(carbon suppliers) to get the consistency right.
I know that’s not really helpful when you’re new to it, but most of us do it by instinct, not by any measured ratio. I know by sight when the greens are getting slimey, that more browns are needed. The aim is to keep the pile moist, not dry or soggy, and living with microbes.
The good news is, you can wing it and still get good compost.
How it Works
During warmer months, it is ideal to turn the pile 1-2 times per week. This aerates the pile, offering fresh oxygen to the aerobic bacteria that are critical to this process. In cold winter, the process will stall, but it resumes during thaws.
In optimum conditions, the pile naturally heats, caused by the bacterial activity, and the various organisms convert the materials to earthy compost. This can take weeks or months.
Compost is so valuable and it’s a total bummer to send food waste to landfills where it rots and attracts vermin. If you have long winters like we do here, that’s a lot of potential compost wasted!
Winter Composting Questions and Answers
1 Can you compost in winter?
Yes. You can definitely save food scraps for composting in the winter. I keep mine in a bin outside as described (above).
How and if the scraps will decompose depends entirely on the conditions and temperature. During deep freezes, everything stops. During warmer spells, it resumes.
2 Do compost tumblers work in winter?
Yes. A compost tumbler (like this Mantis one on Amazon) is a good idea particularly in the winter. An open compost pile may attract vermin while a tumbler should not.
How much the food scraps convert to compost in winter is going to depend on conditions and temperatures. Basically, compost piles naturally heat up with microbial activity which in turn is converting the kitchen scraps to compost (earthy soil for the garden).
During the winter, a full bin with a good mix of greens and browns (see more details here) and adequate moisture may still heat enough at the core to continue breaking down.
A bin with a small amount of ingredients and no insulation from the cold will probably just act as a storage bin until you add more scraps and temperatures warm.
3 Do winter compost piles heat up?
It depends. The larger the pile, the more likely the inner most core area will still heat up despite the winter weather.
I saw this with a large compost pile a neighbor had on his driveway last winter. I would pass it each day on my walks. Even on a frigid day his cat would sleep on it, obviously enjoying some radiant heat as the snow came down. Plus, the snow flakes would melt on it—unless the temperature was far below freezing—so it was definitely actively decomposing despite the season.
A smaller pile would have much less insulation from the cold and may just be dormant during the winter.
4 How can I speed up winter composting?
If you really want to speed things up, first, always finely chop anything you add to the pile. The smaller the bits, the faster they can break down.
Next, if you have an open compost pile, a bigger mass of greens and browns is better for heat, so make it as big as you can in winter.
Realistically, you’d want something at least 6x6x6-feet to have enough mass to counter the winter cold. It’s the warmth within the pile that encourages the microbes (and everything else) to get busy and transform into compost.
A tarp can also help keep heat in and prevent the pile from getting too soggy.
And finally, whenever you get a warm spell, turn the pile as best you can to keep the oxygen flowing. That helps aerate it and further encourage good conditions for decomposition.
~Melissa the Empress of Dirt ♛