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How Do Composting Worms Survive the Cold Winter?

winter composting greenhouseComposting worms help break down food scraps, but how do they survive the cold winter? Any vermicomposting bin set up in a northern state is likely to freeze. Will all the worms die? Should you try to save them? If the worms die, will there still be worm castings for fertilizer in the Spring? Should you bring them indoors?

Worm Resilience

Worms survived for a long time before humans came along. In fact, earthworms are some of the oldest creatures on the planet!

Worms in a worm bin are essentially domesticated. Their behavior remains instinctive. However, putting them into a worm bin means they are under our care. We take responsibility for their well-being. You might have 500 worms in a composting bin made from a tote, or a worm farm with millions of composting worms. Either way, you manage their surroundings.

However, unlike most pets, worms can quickly replenish themselves. Left in a frozen worm bin, many or all will die. If the bin was established well before the cold set in, the worms likely laid eggs. These eggs can survive up to a year in almost any weather. Even if all the worms freeze, new babies should hatch once the weather warms up.

No Pressure

The worm’s natural resilience takes the pressure off the worm bin owner. You can just let nature take its course and do nothing to your outdoor worm bin. Let it freeze. Let it thaw. In the Spring, check for worm eggs, which look like tiny, brown, lemon-shaped spheres. Also, you might see baby worms. Feed them and soon enough, your bin should bounce back.

Worst case, if enough babies do not appear, you can order a bag of composting worms from Uncle Jim’s Worm Farm. Baby worms have a smaller appetite than adults. Therefore, a fresh bag of worms instantly boosts the population of hungry, mature worms. They will quickly digest your kitchen scraps and produce worm castings to put fertilize your garden.

Taking Action

If you decide to take action, you need to preserve or provide some heat. Keeping at least part of the worm bin above freezing is helpful.

If your home is warm enough for you, it is warm enough for your worms. You could move a small bin indoors. For example, a tray-based composter will have most of the worms in the top “working” trays. Move those trays and the base inside. Try under the kitchen sink, or in the laundry room, the basement, or a closet. An indoor worm bin is convenient. No more putting on boots and trudging through the snow! In the Spring, you can move the bin back outside.

Some folks prefer to use a large worm composting bin outdoors and set up a smaller bin inside for the winter. Purchase a handy tray-based composter and dig up some worms from your outdoor composter. Feed them all winter. In the Spring, harvest the worm castings and put the worms back in the outdoor bin.

Check temperatures in your garage or shed. A partially-heated building is better than outdoors in the elements. You should also consider insulating and maybe adding heat (see precautions below).

Insulate and Heat

Worm bins naturally generate a small amount of heat. The process of breaking down organic matter is warming. The center of the bin will usually be the warmest. Worms will migrate there if they are cold.
Insulating the bin helps trap heat in the bedding. Hay bales, straw, scrap carpet, Styrofoam, bubble wrap, insulating foam, or even blankets make good insulators. Put insulation around the outside of the worm bin and secure in place. A couple of bungee cords or lengths of rope could come in handy here. Be careful not to block any air or drainage holes.

Adding heat to the bedding could be a fire hazard if you are not careful. Some worm composting enthusiasts use a seed tray warming mats or lamp to warm up the bin. Keep electrical cords and heat away from combustibles and moisture.

Do What Works for You

Mull over your options and decide what is best for your worms. If you maintain your worm bin, you will have plenty of organic fertilizer to use on your plants.

Check out Uncle Jim’s worm bins, composting worms, meal worms, and supplies. We have been raising worms for more than 40 years. We are the #1 supplier of live composting worms in the United States.

21 comments on “How Do Composting Worms Survive the Cold Winter?

  • Thank you for this informative and helpful post. I have a tower garden that I add your worms to and assumed that they die off in the cold winter, so I replenish them in the spring. My other option is to remove as much of the soil as possible and move them indoors. You’ve given me more ‘food for thought’.


  • Hello there,
    I can’t wait to get started raising worms. But right now in North Carolina we’re experiencing a
    cold spell of freezing temperatures which is going to last about 8 weeks, so…in March I will be
    purchasing 2k worms and put them in a tray-type composter and hopefully that will give me
    enough time to get a routine before winter comes again. I have contacted you a couple of times
    by phone and I want to thank you for your kindness to a novice; I do ask a lot of questions, so
    thank you for your patience with me. I will obviously be talking with you soon. I have a shed now
    and that will accommodate the worms and my storage of the necessary supplies. My goal is to
    sell worms at a reasonable price to local fisherman here at the lake. I have talked to many and
    have told them of my plan and they are all on board. I think this will be a good fit for my retirement. I like to fish anyway so this will be a win/win situation for me! Thanks again for all
    you emails and specials, I hope to take advantage of some of them in the future.

  • I need advice on how to manage the trays. I have lots of worms in all trays. What is the best way to get the worms out of one tray into another so I can remove the castings? Thanks!

  • I’ve purchased worms from you in the past and received an excellent product. However, seeing as how you’re espousing evolution I will not be purchasing from you anymore.

    For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who by their unrighteousness suppress the truth.
    For what can be known about God is plain to them, because God has shown it to them.
    For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world,[g] in the things that have been made. So they are without excuse.
    For although they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened.
    Claiming to be wise, they became fools,
    and exchanged the glory of the immortal God for images resembling mortal man and birds and animals and creeping things.

    Therefore God gave them up in the lusts of their hearts to impurity, to the dishonoring of their bodies among themselves,
    because they exchanged the truth about God for a lie and worshiped and served the creature rather than the Creator, who is blessed forever! Amen. (Romans 1:18-25)

    Evolution is a silly lie. It is willful ignorance of God’s creation. -Nate E.

  • Steve Thaning says:

    Can you put an egg yoke on bread then a quick soak of water to feed. Also the worms seem to like butternut squash, I think there laying eggs inside the skins, but it’s molded. Should I remove food that turn to mold. I have my worms in the garage wrapped with two sleeping bags. Thanks for your answers.

  • We may be getting caught up in defining what life is. In my humble opinion there are two thoughts to consider. One is the form and the other is the life. Perhaps, form lives on in time where life lives on in eternity. Life, being the creation of the Creator, and form being the creation of this dimension of time and physical form. Therefore, it seems to me, this world evolves, while life just continues on through eternity. Perhaps, form gives Creator’s life the ability to “evolve” and remember where we all came from. All one in the Mind of God. Form implies being separate while Mind defines oneness and eternity. Let form be what it has been and becoming and let “Us” as one Mind, come together and see the grandeur of God in all living things. We are all evolving but I think differently than how many might see and interpret it. Bless us all in all forms in all times and in all places.

  • Hi Nate,
    You are right, evolution is a silly lie, but I don’t see anything about evolution in this article.
    What are you referring to?

    Since you are not quoting the true Word of God (KJV), you should include an identification of your selected deviant version, which is obviously not Scripture.
    Using only one verse … 18 (KJV) it actually says,
    “For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness:”
    There is nothing in the actual verse about suppression of the truth, and the verse ends in a semicolon, not a period.
    (A semicolon indicates further information prior to a conclusion; the joining of independent clauses for a single conclusion. A period indicates the completion of the statement.)

    It is nice that you have zeal. But you should learn the truth before you embarrass yourself again.
    It is of utmost importance that your zeal be to God, not religion. As you have made obvious in your post, it is foolish to use a variant version; your version is a pollution of Scripture.

    If you are truly intent on serving God in truth, go to and get a free copy of “The Truth According to Scripture: Book One, Basic Bible Knowledge”.

    And to the writer of the article … Thank you, it was very helpful.

    Glory to God alway and always,
    EW Whitten

  • What is the actual size of an adult red wiggler? Actual size photo would be great on the site. Cant tell if mine are reaching their full potential.
    I have found that in N. Idaho the easiest way to raise and compost is with a bin that I can move into my garage. Its about 50 degrees or more since I put on a pellet stove and work in there many days. I keep the bins under 50 lbs but will split into half that for a bit to dry out for tumbling. Winters outside can get into 15 degree days and 0 nights at worst but 35 to 25 has been the norm this year. I way try a hay bale surround next year outside as a test. Happy worming.

  • Very helpful article. I have two garden towers which are well frozen by now. I also have a worm tray tower that I bring into my basement during the winter and you addressed both areas. I will probably add a few more worms to the towers in the spring. Thank you.

  • Garoleen Wilson says:

    Good info. I was wondering about this very subject.
    My outside worm bin is in a brick lined old well. It’s been filled with sand to about 3-4 feet from the surface. The top is filled with kitchen scraps, straw, peat from the chick brooder and covered with shredded cardboard and a fiberglass lid to keep out four legged visitors.
    I hope we still have worms in the spring.

  • You holy rollers are ridiculous! Great product uncle Jim and plenty of reasonable people will continue to by your worms. Mine live under my crawl space and seem to be real happy at 45 degrees. Yeah for science!!!

  • If you are raising your worms properly there shouldn’t be any stink. If you’ve had a problem with them turning stinky, you are over feeding them. I have 4 bins in my basement for 8 years now and never have had a problem with odor. The soil smells as sweet as the day I put it down there…..

  • Great information. I’m planning a worm fatm, for castings, and fishing worms if possible. First how well do the reds and super reds coexist? Also I was planning on doing it outdoors. The freezing here is 36 inches, I was thinking maybe if I went 24 inches, and insulated with straw, for the winter months, if I could prevent freezing? If anyone has any experience with this please chime in. I appreciate it.

  • Great info, I am in mid-west, not knowing this earlier, I poured all the worms into my raised bed before winter hit in Oct, covered with straw, will check it out after the winter is over and see if there’s any survivors. Am going to order 1 more batch and follow your instruction this year, can’t bare to see all the food scraps going into the trash bin.

  • Testimony to your packing,

    Just wanted to let you know that the last order arrived alive & Well the USPS dropped the ball this time but I must say it is very unusual for them to do that

    They took the scenic route, arrived later than predicted after having been somewhere at the end of the trip for 18 hours in 5 deg F weather (probably in a postal truck) after departing Youngstown and arriving Warren, Oh ( 10 Miles, 20 minute drive ) they arrived in good shape, after tracking their journey on the postal site i have to say I was surprised to find them alive, a testimony to your packaging.

    Thanks again
    Jim Teeple
    Warren, Ohio

  • Deb Armstrong says:

    I love my worms! I am about to share something me with friends, move some to my large compost pile and bring the rest in for winter. I have had a worm farm to in the past but the worms I received from you are the best!


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