Composting in the Winter

Composting is a great way to reduce waste and create nutrient-rich soil for your garden. But many gardeners wonder if you can still compost during the cold winter months when decomposition slows down. The good news is that yes, you absolutely can continue composting throughout the winter!

With the right techniques and setup, your compost pile will keep breaking down materials all season long. Composting in winter just requires a few adjustments to help insulate and maintain heat in your compost.

Can you Compost in Winter?

Yes, you can compost in the winter. While the decomposition process slows down in the winter, it doesn’t totally stop. Bacteria, fungi, and other microbes, as well as larger decomposers like sowbugs, pillbugs, and earthworms, continue to break down organic matter, especially in the interior of a large compost pile or bin. To compost successfully in the winter, you can use the following suggestions:

  1. Gather Leaves: Leaves and pine needles are excellent brown, carbon-rich materials that improve compost pile aeration and reduce odors.
  2. Layer Greens with Browns: Continue to layer greens with browns to maintain an efficient composting process.
  3. Reduce the Size of Greens and Browns: Cutting, chopping, or shredding green and brown materials into smaller pieces can speed up the decomposition process.
  4. Insulate the Pile: Surround the compost bin with bags of leaves or straw bales to buffer against freezing temperatures, or ring the inside of the bin with 6-12 inches of leaves, sawdust, or woodchips.
  5. Harvest Finished Compost: Harvest finished compost to make room for winter additions.

Why Continue Composting in Winter?

Here are some of the main benefits of winter composting:

  • Reduce food and yard waste year-round
  • Continuously produce finished compost for spring soil amendment
  • Allow materials to break down over time so pile doesn’t get overloaded
  • Keep beneficial composting organisms active during cold months

Composting during the winter also allows you to conveniently dispose of leaves, dried plants, and other yard debris instead of having them pile up. As long as your compost gets enough air flow, it will continue decomposing slowly through the cold months.

How Does Cold Weather Affect Composting?

Composting relies on bacteria, fungi, worms, and other organisms to break down organic matter. These decomposers are living creatures that thrive in warm, moist conditions.

In winter, cold temperatures cause these composting organisms to become dormant or slow their activity. Food scraps and yard waste will decompose much slower than in summer.

However, the compost pile itself can generate some internal heat, which helps counteract cold ambient temperatures. As microbes break down materials, chemical reactions occur that release heat.

The key is trapping and retaining this heat energy so that a cold snap doesn’t completely stop the composting action. With proper insulation and heat retention methods, you can keep your compost warm enough to harbor active microbes all winter long.

Choosing a Winter Composting Method

There are a few different approaches to composting during cold weather:

Outdoor Compost Pile or Bin

This involves maintaining your regular compost pile or bin outside through the winter. To boost heat retention, add extra insulation around the bin using materials like straw, leaves, sawdust, or bubble wrap. Turning or mixing the pile less often in winter can also help conserve heat.

Make sure the pile doesn’t get too soggy and anaerobic. Allow air flow by leaving some gaps in the insulation layers or drilling holes in bins. Monitor moisture and add high-carbon “brown” materials as needed.

Indoor Composting

You can compost food scraps year-round by collecting them in a small, enclosed bin indoors. The scraps will decompose very slowly, but this captures the material to be added to an outdoor bin later. There are many types of indoor compost bins that control odors and catch food waste.


Composting with worms can work indoors or outdoors in winter. Maintain worm bins in an insulated garage, shed, basement, or crawl space for composting through cold months. Bedding should be absorbent materials like shredded paper or dried leaves. Avoid exposing worms to freezing temperatures.

Hot Composting

This high-heat method involves building a large compost pile that can heat up to over 140°F through microbial activity. Hot composting requires the right ingredients and techniques to spark a fast decomposition reaction. The heat generated can break down wastes even in winter.

Trench/Pit Composting

For this passive approach, food scraps and yard debris are buried in a pit or trench dug in the ground. The soil helps insulate the compost, while also providing beneficial organisms. Scraps decompose slowly over the winter and can be dug up in spring.

Tips for Active Winter Composting

Follow these handy tips if you want to keep your outdoor compost pile actively decomposing through frigid winter months:

Choose a Sheltered Site

Look for a compost pile location that’s partly sheltered from cold winds, such as along a wall, fence, or treeline. This helps limit heat loss from the compost. South-facing spots receive more winter sun.

Insulate the Bin or Pile

Wrap or cover your compost pile with an 8-12 inch thick insulating layer. Use materials like straw, leaves, sawdust, pine needles, bubble wrap, burlap, or an old blanket. Make sure airflow can still get through.

Add Layers of Bulkier Materials

Stack carbon-rich bulking agents like straw, wood chips, sawdust, and shredded fall leaves between layers of compost. This traps heat and air while absorbing excess moisture.

Monitor and Manage Moisture

Compost should be moist but not saturated in winter. Squeeze a handful to check – it should feel like a wrung-out sponge. Add more carbon material if the pile is too wet.

Turn Less Frequently

Turning or mixing the pile lets out heat and exposes the interior to colder outside air. During cold months, only turn every 4-6 weeks to conserve warmth while preventing anaerobic conditions.

Collect and Store Scraps

Keep collecting food waste in a sealed bin or bag indoors, then take it out to empty into the compost once a week or when the bin is full. This retains heat better than daily food additions.

Use a Thermometer

Check that the center of the pile is staying between 110-140°F. This indicates active composting. Turn and add insulation if the temperature drops below 100°F.

Size Matters

A larger compost pile holds heat better. Make sure your winter pile is at least 3’x3’x3’ to generate enough heat through decomposition. Smaller piles lose heat quickly.

With a well-constructed and insulated compost pile, you can keep those microbes munching away on organic waste all winter long!

What to Compost in Winter

Nearly any biodegradable material can go into winter compost, but some ingredients break down faster than others in the cold. Here are some of the best things to compost over winter:

  • Fall leaves
  • Crushed eggshells
  • Tea bags/coffee grounds
  • Newspaper/paper bags
  • Chopped woody brush and twigs
  • Livestock manure
  • Vegetable and fruit scraps
  • Shredded cardboard
  • Sawdust and wood chips
  • Straw
  • Dried grass clippings
  • Houseplant trimmings
  • Cotton and wool rags
  • Nut shells
  • Pine needles

Avoid adding thick, dense materials like corn cobs, avocado pits, or walnut shells, as these break down very slowly. Meat, oils, and dairy scraps may also have trouble decomposing fully during cold months.

Troubleshooting Cold Weather Composting

Even with the best preparations, compost can run into problems over winter. Here are some common winter composting issues and how to fix them:

Pile Freezes Solid

  • Add insulation and increase pile size
  • Mix in bulking agents like sawdust or straw
  • Turn pile to introduce air and break up frozen sections

Slow Decomposition

  • Monitor temperature and turn more if under 100°F
  • Make sure pile gets oxygen – turn or add airflow paths
  • Insulate sides and cover pile to hold in heat
  • Introduce compost accelerators like manure tea

Bad Odor

  • Indicates anaerobic conditions – turn pile promptly
  • Add coarse carbon materials to improve aeration
  • Do not overload pile with too many dense, wet greens

Food Scrap Accumulation

  • Bury scraps into hot center of pile, don’t just pile them on top
  • Let each layer of scraps decompose before adding more
  • Remove any undecomposed scraps in spring

Vermin Issues

  • Eliminate food scraps on soil surface or bin edges
  • Layer green waste immediately after adding food
  • Use wire mesh to line bin walls and prevent entry

With a few adjustments and proper maintenance, your compost can keep working even when temperatures drop below freezing. Don’t let winter stop your composting habits! Follow these tips to sustain healthy decomposition and stockpile great organic matter for spring.

Frequently Asked Questions About Winter Composting

Can I start a new compost pile in winter?

Yes! You can start a brand new compost pile in winter. It may heat up and decompose more slowly at first, but materials will begin breaking down right away. Follow all the same basic composting principles and insulation methods outlined above.

What’s the minimum temperature for composting?

The composting process can take place down to about 40°F, but it occurs very slowly. Optimal composting happens between 90-140°F. Below 55°F, microbial activity declines rapidly. Insulate piles to keep the interior above 55°F.

Should I cover my compost pile in winter?

Yes, it’s recommended to cover and insulate your compost pile over winter. This helps trap heat inside and keep the decomposing materials warmer than outside air temperatures. Use an insulating blanket, tarp, burlap sacks, or thick layer of straw/leaves over the pile. Make sure airflow can still get in and out.

Can I add food scraps to compost in winter?

Absolutely. Food scraps can still be added to an active compost pile all winter. Fruit/vegetable scraps, coffee grounds, eggshells and more provide valuable nitrogen. Bury the scraps deep into the hot center of the pile rather than just dumping them on top.

How often should I turn the compost in winter?

Turn less often in cold months – only once every 4-6 weeks. Frequent turning lets heat escape and slows decomposition. Monitor temperatures and turn again if the pile drops below 100°F or starts to smell bad.

What happens if compost freezes?

It’s normal for compost to freeze solid during sub-zero winters. The microbes go dormant but don’t die off entirely. They will restart activity once things thaw out. Turning the pile helps break up frozen chunks. Insulating better next year can reduce full freezing.

Can I compost in a worm bin over winter?

Yes, vermicomposting can work year-round if the bin is kept above freezing. Move indoor worm bins to an insulated garage, basement or crawl space in winter. Monitor moisture and add food in moderation during cold months.

How long does composting take in winter?

Expect the composting process to take 2-4 times longer in cold weather compared to warm conditions. But materials will continue decomposing slowly in a well-managed pile. Finished compost is ready when the original contents are no longer recognizable.