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Composting Worms and Freezing Cold Weather

winter garden freezing cold compostingWhen the weather outside is frightful, you may worry about how composting worms survive the freezing weather. Winter temperatures can fall below freezing in most parts of the continental United States. What happens to composting worms in low temperatures? Is it important to prevent Red Worms or European Night Crawlers from freezing? How does temperature affect the composting process?

When It Is Cold

When temperatures plummet and stay low for a long time, everything starts to freeze. The lakes and even Niagara Falls develop a thick solid coating of ice. The ground becomes hard and almost impossible to dig into. Precipitation falls as snow, and the white flakes accumulate on all outdoor surfaces.

Human-made systems malfunction. Exposed water pipes freeze and burst. Even automobile windshield washer systems get clogged if contaminated with water. Ice crystals can wreak havoc if we are unprepared.

However, nature handled freezing temperatures for a long time before humans came along. Earthworms found ways to survive. Some worms dug deep or found warm places such as near hot springs. Worms also laid eggs and left the cocoons protected in the ground. Cocoons are designed to survive the winter.  Therefore, new worms hatched when the weather warmed up in the spring. This new population carried on the crucial task of breaking down organic material into fertilizer.

Human-Made Composters

We learned to harness the power of composting when we began farming. Composting would have been a standard technique for improving the fertility of the land. For example, clay tablets referring to manure in agriculture were made by the Akkadian Empire in Mesopotamia more than 4,400 years ago.

In modern times, organic farmers still rely on composting to produce natural fertilizer. We have found that concentrating worms in a composting bin makes the waste vegetation break down faster. This is called “vermicomposting.” Fast breakdown is important to everyone, especially urban and suburban households. City folk live in tighter quarters, and do not have much outdoor space for composting. Thus, they turn to composting outdoors, on a patio, or indoors, using worms.

Composting Outdoors

A traditional outdoor vermicomposter is usually confined to a bin or barrel. The composting worms have nowhere else to go. As their caregivers, we are obligated to give some thought to their care. Here are the options:

  • Move the worms indoors. This could mean setting up an indoor worm bin, or moving the current bin inside (if feasible).
  • Insulate the bin or move the worms to a semi-heated area. Test the temperatures in your garage or shed. Depending on the building, they might be a few degrees warmer than outdoors.
  • Provide some heat. When set up correctly and safely, a warming bed or lamp can help. See safety precautions before considering this idea.
  • Leave the worms outdoors and let nature take its course.

Keeping Worms Outdoors

Leaving composting worms outdoors might sound harsh. If you are emotionally attached to this specific generation of worms, move them inside. However, Mother Nature set things up so the worm population will carry on.

The worms will try to take care of themselves in the confines of the bin. They will naturally migrate to the warmest part of the bin. This will usually be the center, down deep. If you do not see worms on top, do not worry. They likely dug down looking for protection. Leave them be. Continue to feed them by burying the food under a small amount of bedding. The scraps will continue to break down, just more slowly. Also, colder worms will eat less. The composting process itself generates some heat.

An established, healthy worm bin will contain worm eggs inside of cocoons. They are dark and shaped like lemons, about the size of a grain of rice. Even if you cannot see them, have faith in your worms! If the eggs are there, you will see little baby worms when the weather is consistently warm. They will grow into full-sized composting worms. And they will dutifully break down kitchen scraps and waste vegetation.

Worms Speed Things Up

A large amount of scraps may have accumulated in your worm bin or freezer over the winter. Spring is when you need the most finished compost for your garden. The worm population might not bounce back in time. Or, if there was mass die-off and no babies, the worms might not recover. If necessary, purchase a bag of composting worms from Uncle Jim’s Worm Farm. Add them to the top of the composter and they will dig their way down.

If the weather is below freezing when you order worms, they could freeze in your mailbox. Just choose “Yes please” to the question “Hold your worms at your local post office?” on the product page.

Don’t let cold weather stop you from vermicomposting. Composting with worms diverts food and garden waste out of landfills. The resulting fertilizer is excellent nourishment for your garden and indoor plants. Got questions about vermicomposting? Connect with Uncle Jim’s Worm Farm on social media, and browse our blog.

19 comments on “Composting Worms and Freezing Cold Weather

  • Thank you for this post. I don’t have any worms as yet; but, it can get really cold here in central WA. Right now, though, it feels like Spring is in the air, with temps in the 40s. It will probably get cold again before the hot weather comes back.

    • I’m new to this worm composting process (4 days) but have already made some observations which confirm Uncle Jim’s info on cold weather worm activity. My worm bin is in a work shop in my barn. I heat this area with wood and never let it freeze. The temperature inside of the rooms does how ever hoover around 40 degrees Fahrenheit as a low point. The bedding contents in my bin declined to the low 40’s after 24 hours and I had to dig down to find my little guys. The were still healthy but buried. I put a 100w lite bulb about 8 inches below my, upward migrating home made, worm house (it has 12″ legs) this heated the bottom of the worm bin to a warm comfortable to the touch feel. I monitored the bedding temp and over 36 hours it raised to from the low 40’s to about 69 degrees. Now my little guys are in a food eating frenzy in the top layer of the bin. I turned the light off at 69 degrees to not overheat the guys. I will monitor ever 12 hours or so and try to keep the temp between 60 and 70 degrees. I want my guys to eat at a maximum rate as I am trying to use up all of the edible kitchen scraps that we generate. There’s only two of us but we generate a lot of fruit and veggie scraps not to mention more coffee grounds than I can use in my feeding. I think I’ll probably have to make an additional bin soon.

    • carol christianson says:

      I add fresh horse manure in the winter to my outdoor bins, usually just a layer on top. It seems to help keep the compost pile warmer and the worms can get to it if they want. I try to bury the food scraps below the compost so the worms can choose not to go thru the horse manure if it’s too “hot” for them. Seems to work well, and by spring the manure is favored by the worms…yum yum.

  • I had to move my worm composter inside . It sits in my Dining room.LOL. My wife complains about knats and you can see them come out when I open the lid. Any suggestions ? I already suggested to her a new wife but it didn’t go over well.

    • Hey Jim,

      We had the same issue at my house. I have three large bins in our utility room and it was overtaken by fruit flies/gnats. Eventually they traveled through the duct work and we were seeing these gnats everywhere in the house. I tried setting traps but I think I let it get too far and could not gain control. We ended up placing them in the garage, or outdoors, for a week to allow for the gnats to either fly away or die due to cold exposure. In that same time, we beefed up our vinegar traps throughout the house and were careful not to leave any fruits on the counter. After a few weeks we were able to beat the invasion and have placed the bins back in the house without any further issues.

      If you’re successful you’ll have to make sure that you’re not accidentally inviting these pesky flies to your home. I live in MN so this time of the year everything outdoors dies. However, come spring, summer, and fall, we’ll have to be careful or simply place the bins outdoors again. Hopefully this information helps. It was very challenging for us as I slowly noticed they were not simply staying in the bins. Good luck.

    • Michael Price says:

      Are they gnats or fruit flies? Can’t tell the difference? (I still can’t). Start easy and work up as needed.

      Both: Lay down a layer of fresh bedding every time you add to the bin. You want it to be pretty dry. You can add a little water after a few days but you want to do your best to keep the very top dry. This has proven helpful with most pests.

      Fruit flies: Hard to completely stop them but you can easily slow them down. In a small cup, mix Apple cider vinegar and a few drops of dish soap. Leave close to the container.

      Gnats: If you have gnats, your bin is probably too wet. Yellow stick tape works, as well of the occasional layer of Gnat Nix. You may want to check indoor plants for gnats, as that’s probably where they originated from.

    • In addition to the other tips here, I’ve had really good success with nematodes when my bins get gnats. The species is Steinernema feltiae, and I’ve used the Scanmask brand. It is available online from several sources, including amazon. The nematodes only attack larva, so it takes a week or so before the number of adults will start to decrease. Because of this I’m pretty aggressive with applying the nematodes, ordering and applying them as soon as I see any adult gnats. That seems to keep things under control without having the clouds of gnats coming out of the bins.

  • yvonne moore says:

    I want the liquid from the worms also, is there a bin that will allow them to go down and when it’s warm come back up if they are outside

  • Try a freestanding used plastic laundry sink for worm bin. Have used for 15 years plus in arid/hot climate. Drill extra holes in bottom on one end near drain and opposite side. Keep 5 gallonbuckets under drilled holes. Water once/twice a week (adjust to your climate) and you will have large quantity of tea without much effort. May not be as pure but is very easy.

    Also easier to sort worms at this height especially if you have more than one sink. (watch at yard sales – should pay no more than 20.00 max). I keep bins in shady area outsidoors with an old throw rug/carpet on top. Worms have survived down to 5 degrees Fahrenheit. While adding food and sorting watch out for scorpions/black widows if you live in southwest.

  • My first time to try vermicomposting. Bins are in the garage where temp. does not drop below freezing, but does hover pretty close. I live in just west of Dallas, Tx. Any suggestions for protecting my worms, or do I need to do anything at all? I have two bins for red wigglers and a new one started for a small trial of European night crawlers. Thanks for any suggestions.

  • Hi guys!
    I made a raised bed garden (about 200 sq ft) and am ready to add worms to it. They’re about 30in tall with lots of logs and sticks at the bottom (hugelkultur). About the top 16 inches is garden mix with our own chicken manure and wood chips broken down and then I added 165 gallons of spent grains from a brewery and tilled it all together.
    I’m in Memphis TN Zone 7B.
    I’m wondering how many worms I should add and if I can add them now while it’s still cool?
    Thanks so much.

  • Mountain Anderson says:

    What happens if I buy worms in the winter. Will it be to cold for them and will they die when they arrive at much house?

    • Hello and thank you for your question! We ship our worms year round. We will hold shipments in really bad weather but for the most part, they will ship out and do just fine. if something should happen to them in transit, we will replace them or refund you for your order. All you need to do is contact us and let us know. We may require a photo of the dead worms for our records so if possible please take a photo of their condition upon arrival. That helps us out with future shipments.

      Uncle Jim’s Worm Farm

  • Sandra Krokaugger says:

    I’m going to try worm composting next Spring. I’m in the higher elevations of Utah so it freezes here in the winter. This is my plan: bury the composters into the raised beds with holes in the sides so the worms can travel in and out of the bin. With a little luck they will thrive in the spring, summer, and fall enough to become a healthy population. The beds don’t have anything under them like weed barrier so I predict the worms will work their way down under the raised beds in the winter. Is that all a fair assumption?


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