Common Vermiculture Questions


What do earth worms do when it gets really cold out?
Question asked by Suzanne of ‘all my heart sees’

Designs – Earthly Comforts – Inspired by Nature – see collection here

Suzanne asked recently, “What do earthworms do when it gets really cold out?” which is a cracking question.

It’s undoubtedly a topic l pay attention to especially given my wormeries are all sited outside in their towers. For me, l spend a considerable amount of time working on insulating the boxes, but also, my farms are pretty deeply soiled, to begin with. This makes an escape for some of the residents easier.

In the summer of this last year, the worms burrowed into the soil into the basement sump or dampest section of the farm to escape the heat. I have noticed this over the last couple of years, especially since working with wooden worm boxes of 36″ – 48″ depth that the residency at any one time is never just on top of the farm but can be found usually at around the 8 – 25″ depth line.

When fresh food is added, they travel upwards to eat and retreat to their burrows again when finished.

Whilst the soil depths offer some protection against various temperatures – be this hot or cold – l also place additional shredded paper and leaves in the colder months to the existing top substrate layer of the farm’s surface. Standard paper depths are around 3″, whilst winter depths are around 6″.

The tower farms have waterproofed lids, preventing surplus water from entering and causing over moistness or dampness or frosts to the soils. But they are also ventilated, which aids the airflow.

Earthworms can’t survive for long in prolonged temperatures below freezing so much of the time. They stay within their burrows deeper in the soil. If the temperatures are continued, they will coil themselves tightly into a protective mucus-coated [slime] knot ball and enter a stage of estivation which is a bit like hibernation. The slime keeps the worm warm by lowering the freezing point.

They will stay in this status till conditions above ground improve. They will also prepare for this period by taking organic materials down to the burrow. Some species can be found at a depth of six feet beneath the surface.

With the wormeries in the winter months, everything can slow down.

Although adding food to the farms can generate heat, increasing the temperature and keeping the worms active.

I also know from experience when l was warm composting and had a worm farm within the heap that the whole decomposition process keeps the worms warm as well.

Worm farms are most active in temperatures between 55 – 75 degrees Fahrenheit and so if those temperatures are not present. As long as it doesn’t drop below 32 degrees Fahrenheit, the worst that happens to the farm is that activity will slow down. If it gets seriously colder, worms start to escape the conditions to look for alternative habitats and more pleasing conditions.

Currently, the temperatures l encounter here is not so much ‘cold or even freezing but wet, so l make sure that my farms remain dry. But if the worst were to occur, l would work on insulating the farms more than they currently are by using perhaps old rugs or even strips of carpet and securing them to the outside edges of the farms.

Something l have done before, which aids, is to add 3-4″ of fallen leaves to the surface of the farms above the soils, which acts as a form of upper mulch and then add 3+” of shredded paper.

I can then scrape the paper and the leaves to one side and put the foods in, which during winter is around once every 4 – 9 days pending consumption. I watch their eating habits very closely because my farms are outdoors, and activity and production can slow down, and l don’t wish for the food to go bad, which could produce acidic conditions.

Something l will be trying this winter is the feeding of more grown grasses; l played with the concept over the summer, and it performed pretty well. The secret l learned was not to let the grass grow to more than three inches high.


This organic feeding method may assist in keeping the worms warmer without the need for kitchen waste.

Tower Farm Wormeries

So there we go Suzanne – perhaps a bit more comprehensive as we looked at both earthworms and farming worms – however “What do earthworms do when it gets really cold out?”

Common Vermiculture Questions Directory

Vermiculture Directory

Published by The Autistic Composter

Howdy Folks, Earthly Comforts is a broad niche wildlife journaling scrapbook focusing on the countryside, wildlife biodiversity and environmental conservation, flora and fauna volunteering projects, gardening, composting and vermiculture, also known as ‘worm farming and photography too.

10 thoughts on “Common Vermiculture Questions

    1. Hey Ruth, the best ‘earthworm condition’ is moist and this is due because they breathe through their skin.

      Wormeries need to have a moisture level of around 60% so that when you grab a handful of soil and squeeze it’ll feel like squeezing a damp sponge but not a wet sponge. So moist and crumbling and not sodden and dripping wet dirt.

      It’s a question l’ll address in more detail this week 🙂

      Liked by 1 person

  1. Hey Rory, thanks for the really great comprehensive answer! I had no idea how deeply they might travel due to weather conditions. They can really burrow! And the slime knot they can go into, that’s neat. ☺️ It leaves me wondering about what I can’t see that’s going on under the ground all the time. It’s pretty neat how you’re able to check and see where your worms are in the farm and thus how they’re doing with current conditions. Thank you! ☺️

    >

    Liked by 1 person

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