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Compost worms won’t be able to survive outside in the winter themselves. These worms work best within a certain temperature range, which is between 55 to 77 degrees Fahrenheit (around 12 to 26 degrees in Celsius). Temperatures that are lower or higher than that range will cause them to become lethargic and even decrease their appetite. In those cases, they might try to escape the circumstances by burrowing underground or moving to a more hospitable location.

If the temperature falls severely out of that range, compost worms will likely die if they’re not transferred to a more insulated space. The temperature requirement caps at 80 degrees Fahrenheit in warmer climates, any higher than that and the compost worms won’t have a chance to survive. During the winter, temperatures below 32 degrees Fahrenheit will freeze their bodies and effectively kill them.


Why can’t compost worms survive in the winter?

Compost worms are a type of earthworm called red wigglers. They are experts at breaking down organic matter such as rotting food, vegetation, manure, and other compost. Unlike earthworms, red wigglers are epigean, which means they do their work on the surface rather than underneath the soil. This characteristic makes them more sensitive to changes in temperature, in addition to the fact that their bodies are made up of 90% water, which certainly isn’t ideal in freezing temperatures.

How do you help your compost worms survive the winter?

The easiest solution is to move your worm bin inside to share your warm, insulated home. An added advantage is that they’ll happily take your table scraps too. In most cases, this is the best option to ensure their survival and keep them actively decomposing material.

However, if your housemates are squeamish and don’t like the idea of having worms inside the house, you can also opt to move the worm bin in the shed or garage. The darkness and added insulation will help keep them warm and busy. Just make sure to provide an additional heating source such as a heating pad or space heater if the area is not connected to your central heating system.

You can also choose to bury your worm bin underground. Simply dig a hole larger than the worm bin and insulate the surrounding space with twigs, leaves, straw, or any material that won’t retain water. You can even use styrofoam! Make sure to layer more dry material on top for added insulation, but use a material that will be easy to remove later on. Lastly, provide them with enough nitrogen-rich food to last them the whole winter.

If you’re left with no other option, you may leave them outside if the compost bed is large enough and they have adequate shelter. Microbial decomposition generates a small amount of internal heat and if the bed is big enough, it may retain more heat, maybe even just enough to allow the compost worms to survive. However, this is a risky option and it’s likely that some of your compost worms will die off.

To do this, simply mimic a greenhouse environment by covering the bed with heavy-duty clear plastic. This will help trap the heat being generated by the decomposing process. The worms will likely gather in knots to try to escape the cold and keep warm. However, even if this method fails and your worms die off, their cocoons will survive and will be ready to hatch in the spring.


To ensure your compost worms survive throughout the winter and make it to spring, consider doing any of these viable options. Compost worms will survive the cold season as long as they’re kept in an insulated area with the right temperature conditions. In addition, don’t forget to maintain the optimal moisture level in their bedding and provide a regular food source to keep them happy and well-fed.