Composting in cold weather can be a challenge, but it’s by no means impossible. You just need to give your compost pile a little more TLC than in the warmer months.
The key is to plan ahead before winter arrives in the fall. Trying to resuscitate a failing compost pile when its below freezing is a difficult task.
In this article, I give you 8 actionable strategies to prepare your compost pile for surviving and thriving through the winter months.
I also talk about how you can keep your outdoor worm compost pile alive in the winter.
Let’s dive right into it! (Not the compost pile, but the article!)
Horse manure is great for keeping winter compost piles warm!
Table of Contents
The Basics of Composting
In order to have a productive compost pile survive the winter, you need to understand the basics of composting. I will touch on the foundations of a good compost pile, but if you want more in-depth information, I suggest heading over to my Foolproof Guide to Composting article.
The goal of a compost heap is to get the pile to warm up through a biochemical reaction. Basically, you are feeding microorganisms that work to break down the organic materials you feed to it. The microbes require oxygen, moisture, and the proper ratio of materials.
It is critical to classify the material you build your pile with. The two types of materials are:
Brown materials are typically made up of carbon, decompose slowly, and are the fuel the microbes need to break to break down the green matter.
List of Brown Matter Material:
- non-glossy paper
- paper towels
- woody material
Green matter is nitrogen-rich, quick to decompose, and feeds the microbes proteins so it can reproduce.
List of Green Matter Material:
- all vegetation that is not dry
- manure (from herbivore animals)
- kitchen scraps (non-meat)
- fresh grass clippings
- fresh yard waste
To start your compost pile, start with a layer of brown matter about six to eight inches in depth.
Next, add your green matter on top of the brown matter. The reaction between the brown and green matter is where the composting magic happens. The microbes have the fuel and food necessary to cause the thermal reaction which breaks down the materials and makes heat.
Cap off your compost pile with a layer of brown matter. The thickness can vary, from a few inches in the summer, to six to eight inches or more in the winter.
Heat is what keeps the compost pile alive and thriving through the winter months.
How to Compost During the Winter
Why is it so difficult to compost during the winter climate?
Because the biochemistry of the compost relies on heat to activate the microbial process of breaking down the waste.
A frozen compost pile will become inert and will not reactivate until warmer temperatures come about.
Many composters are at peace with their piles hibernating during the winter. But you do not have to wait out all those cold months for your pile to keep being productive!
The trick to a compost pile producing in the winter is keeping your pile warm and toasty.
Strategy #1: Start with a healthy, productive compost pile
As the winter months draw near, your compost pile will have a better chance of success if it is healthy and warm going into the colder months.
A moist pile is good for the summer but has a higher chance of freezing in the winter. Therefore, you will need to add more brown matter to your pile in order to keep it a little drier, but not too dry.
Start by slowly building up the brown matter in your pile in the fall, and increase the brown matter as the temperature keeps dropping.
Finding the sweet spot between brown to green is more of an art form than a science, so check on your compost pile a couple of times a week and adjust ratios as necessary.
Tip: store bags of dry leaves for brown matter
Store extra leaves in the fall to amend your pile through the winter. Leaves are an easy source of brown matter and are an essential ingredient to keep the heat going in the pile.
The leaves will work to wick away moisture from the pile which is vital to maintaining the winter composting process.
Just a couple of contractor bags full of leaves should be more than enough to get your pile through the winter months.
Strategy #2: Insulate your compost pile
Your compost pile naturally makes its own heat in the decomposition process, but in the winter the heat can slow, and in extremely cold temperatures it can become altogether dormant.
Insulating the pile can help keep the warmth in and keep your compost kicking.
A dark-colored tarp thrown over the top and wrapped around the sides will attract the warmth of the sun and keep heat in.
You can also place a thick layer of hay on top of the pile to keep the warmth in and the cold out.
Winter Compost Insulation Ideas:
- Hay bales
- Pre-built outdoors composting container
- Emergency blankets
- Old blankets
- Old carpet
Strategy #3: Place your compost pile wisely
If your pile is in a barren area that is exposed to the elements, chances are it will freeze solid during the winter.
Relocating your pile to a more protected area that provides shelter gives your pile a higher chance of surviving the winter.
Place your pile near a structure or around thick brush to help deter exposure.
Some more placement ideas:
- Build a protective wall for wind protection
- Place on the low side of a hill or mound, preferably away from the wind
- Move your pile to a barn, garage, or outbuilding
- Tuck into a grove of trees or stumps
- Place in a small gully (as long as moisture is not a concern)
- Surround with mounds of dirt
Strategy #4: Add your Materials in Thoughtfully
In the warmer months, we don’t have to be so concerned about how often and how little material we add to the pile. In the winter, it is paramount to consider how much and how frequently we add to the pile.
Tip 1: add your materials in bulk
Adding in a table scrap here or there will do your pile a disservice in the winter.
When you collect scraps and add in bulk, the material will retain more heat. If you disturb your pile by stuffing in a little here and there, you are risking your pile losing heat.
Collect your green matter in an old coffee can or tabletop composter and only add to the pile once full.
Tip 2: Shred chunky, large material
Bulky matter will take longer to break down and require more heat to process them.
Give your winter pile a jumpstart with shredding, cutting, and breaking down both green and brown matter before adding to your pile.
Tip 3: Layer your materials properly
Maintaining the golden ratio of composting is key to creating the heat necessary for your pile to keep breaking down matter.
The typical ratio is 30 parts carbon to 1 part nitrogen. However, no two piles are alike, and taking the time to try and calculate ratios is a cumbersome task.
The best rule of thumb is to add 6 inches of brown to start your pile, add some handfuls of green in the middle of the pile, and add a final brown layer to cap it off.
Over time you will get a feel for the ratios for your pile, and it becomes more of an art form than a science.
Just remember to go a bit heavier on the brown during the cold winter months and adjust as necessary. Keep your pile on the drier side, but not to dry.
Strategy #5: Do Not Turn the Compost Pile
Mixing the pile once or twice a week is standard in the spring, summer and fall.
However, in the winter, when you mix your pile you displace the heat, causing your pile to cool.
The only time you may need to turn your compost pile is if your pile is getting slimy and stinky. Add some brown in and turn the pile gently.
Strategy #6: Add Hot Material to your Compost Pile
Adding some hot nitrogen-rich materials can keep the heat going as well. This can be coffee grounds, horse manure, or poultry manure.
You can also try super-hot nitrogen such as lobster, crab, shrimp, or crawfish, but keep in mind this will attract some unwanted critters.
If you think you don’t have enough microbe activity in your pile, you can add a handful of potting soil to your mix for inoculation.
When it gets too cold out, your pile will freeze no matter what you do.
Let mother nature take its course and tend to your pile when a warming trend occurs.
Strategy #7: Trench Composting in the Winter
Trench composting is an excellent solution for the winter as it is low maintenance and can help amend a section of your garden that needs some TLC.
Select an area of your garden that you want to add some composting love to. Dig a trench about one foot deep along the section. Pad the bottom of the trench with three to six inches of brown material (not necessary, but recommended).
When your compost bin fills up, dump the green matter into a section of the trench, and lightly cover with some brown matter and soil. Each time the bin is full, fill another section of the trench.
The heat from the ground will keep the pile insulated and the goodies from the compost will nourish your garden section.
Strategy #8: Move Your Compost Pile Indoors
In some regions, it gets far too cold to keep a compost pile warm. If you don’t want to wait out those winter months, you can opt to move your compost pile indoors.
All you need to do is shovel your compost pile into a bin. You can either drill holes on the bottom of the bin and place a tray underneath to catch the compost tea, or you do not drill holes on the bottom and keep an eye on moisture control.
I go into way more detail in my Apartment Composting Guide.
Can You Do Outdoor Worm Composting in the Winter?
It is possible to keep your worms alive and kicking in your outdoor compost pile, but there are some factors to consider.
The first factor to consider is the type of worm that is in your compost pile. Some earthworms always live in the upper soil levels and in leaves.
These worms do not dive deep for winter and die when the ground freezes. They lay eggs in protective sacks in the fall and the baby worms hatch in the spring.
Other earthworm species, like nightcrawlers, dive deep below the frost line to survive the winter.
The second factor to consider is how deep the frost depth is in your area. The farther north you go, the deeper the frost depth will be in the soil. You can determine the frost depth in realtime here.
The third factor is how you have your compost pile set up. An above-ground compost pile will have a higher chance of freezing rather than a pile below ground. If your pile is deep enough to be below the frost line, chances are you will still have active worms in your pile.
Winter Composting Conclusion
Yes, you can definitely compost during the winter, it just takes some thought and planning to make it happen.
The primary takeaway is that you need to keep your pile hot. Heat is key to your compost not freezing solid.
A pile that starts off healthy and hot will have a higher chance of surviving the winter.
A pile that is either below ground, sheltered from the elements, or even moved indoors will probably make it.
Just be prepared and take the steps needed in the fall before the freezing temps arrive, and your pile should fare just fine.
If you are interested in learning more about composting, check out my collection of composting articles.