Everyone knows composting requires heat, even if you skip the thermophilic (second) stage. In many cases, you can simply switch to indoor composting in winter, but what about a compost pile that already exists outside as winter approaches?
Is it all for naught? Or can you compost in winter successfully?
Logic might say the cold prevents thermal degradation. Still, the reality is that there are ways to keep compost warm enough to continue processing – albeit at a slower rate – throughout the winter.
9 Tips For Composting In Winter
While it’s possible to compost during the winter, there are a few rules you’ll need to follow.
Here are some important tips to ensure a successful winter composting session.
Tip 1: Check The Temp
Internal temperature is essential to compost, and proper composting will require an internal temperature of 120° degrees Fahrenheit (with the potential of as much as 140° degrees Fahrenheit).
Composting can occur if the internal temperature reaches a minimum of 90° degrees Fahrenheit.
So one important thing is to keep an eye on the internal temperature of your compost pile and ensure it meets or exceeds this minimum temperature requirement.
However, external temperature also plays an important role, as water is a key factor in proper decomposition.
If the external temperature drops below freezing, there’s a risk the water in your compost will also freeze, completely stalling the process.
Turning the pile or adding more nitrogen-rich materials can help keep the process going, but you will also need to deal with other potential roadblocks for the best possible results.
Tip 2: Size Matters
There’s an old saying, “size doesn’t matter; it’s what you do with it.”
While this is certainly true of winter composting to a degree, outdoor compost piles will have a distinct advantage when size comes into play.
Small piles are less likely to maintain their core temperature, although they can survive in airtight containers.
On the other hand, a large compost pile is far less likely to freeze through and will need less insulation.
Tip 3: Insulate
Speaking of insulation, you’ll want to insulate any bins to help keep the temperatures above freezing on the inside.
This involves many simple techniques, such as ensuring the container has direct southern exposure but has shelter from the other cardinal directions.
Garbage bags filled with dried leaves (make sure they’re dry!) or similar materials make great insulating material for piling around the sides of a compost bin that need shelter.
A layer of straw, leaves or other insulating materials around the base (or under a raised container) can also help prevent the container from getting cold.
A tarp over the top and secured around three sides can also help provide great insulation at a low cost.
Tip 4: Swap Out For The Season
Winter composting has some slightly different rules for what you can include, which we’ll cover in a moment.
In the meantime, when frost is approaching, it’s important to prepare for a changeout.
This is the best time to remove all completed compost, which can then be stored in insulated bins for the spring.
Remember, composting slows down during the winter, so your compost pile will grow faster than it can shrink.
By removing the completed compost, you’re ensuring you have the maximum amount of room for the process to continue.
Tip 5: Good and Bad Materials For Winter Composting
The first contributions to your compost pile going into winter will differ from your usual batches, although many of the ingredients remain the same.
For example, leaves are readily available and will be a large percentage of your green material.
On the other hand, avoid large sticks or woody components, as they can further interfere with an already slow process.
These should be either run through a chipper, ground into sawdust, or turned to ash before adding.
As always, avoid using anything that’s been treated with chemicals, including pesticides.
Any excess brown material (dried leaves, twigs, etc.) should be securely bagged so they can be added during turning, as brown materials will become harder to obtain.
Tip 6: Moisture Control
Having enough brown material is absolutely essential during winter composting, as this helps control moisture levels in sealed containers.
But any container can be at risk for oversaturation during the winter months, so you should constantly monitor how wet your compost is getting.
Add more brown materials as needed and avoid letting the compost come into direct contact with the ground, where it might soak up nearby permafrost.
You will also want to keep an eye out for condensation inside the composting container, which means more insulation will be needed.
Tip 7: Hybrid Vermicomposting
Vermicomposting is the wonderful art of letting worms do the work for you and is a very common indoor method that results in valuable worm castings.
However, when winter approaches, you can employ the same worms that are used for vermicomposting with your outdoor (contained) compost pile to give it a bit of a boost.
Just remember that all of the same rules used in vermiculture and vermicomposting apply to your outdoor compost pile if you want happy, healthy worms (and even more nutritious compost).
Tip 8: Turning
One important caveat regarding your compost pile and heat retention is that you want to reduce how often you turn it.
While this process is best done every 2 to 3 days during warmer months, turning too often can chill the entire pile during winter.
Try turning once weekly (and reduce this frequency if you notice a significant temperature drop inside the pile) during the warmest part of the day.
Working quickly or further shelter yourself and the compost from the elements while you work can also be a huge help during this important step.
Tip 9: Moving Indoors
With all of that said, smaller compost piles can be brought indoors for the winter if you have airtight containers.
Several methods of composting indoors may allow you to convert from your current composting method.
Do a little research to see if one of these indoor methods will be a better solution for you or if you should enlarge your outdoor compost pile for the cold season.