Don’t Let Unexpected Toxins Wipe Out Your Worm Herd

Don’t Let Unexpected Toxins Wipe Out Your Worm Herd

Wanna know how to keep your red wigglers safe from toxins? Yeah. I did too. Especially since finding out we are surrounded by loads unseen toxins Yikes! 

They’re out there all right. Toxins are dangerous to humans, pets, plants, and really mess things up for our worms. So I figure I’d better tell you where they lurk and how to avoid them as well. 

This month, instead of learning what to put into the bin, you’ll learn what to keep OUT of it. Plus, we’ll discuss a few ways to deal with those questionable materials you aren’t sure are safe. 

Toxins Defined

According to the Oxford dictionary, toxins are “antigenic poisons or venoms of plant or animal origin, especially those produced by or derived from microorganisms and causing disease when present at low concentration in the body.” Wo, that’s a mouthful. And only part of the story. 

We all know certain things growing outside can be poisonous. But did you know that all plants have toxins? In nature, they are used to protect plants against herbivores as a means of survival. 

Believe it or not, even after a plant has completed its life cycle, these agents can remain in the dead material.

Natural Toxins From the Garden

It’s not all bad though. What is toxic to one may present no danger to another. For example, peanuts, soy, milk, and eggs. These contain deadly toxins for some, while others safely consume them daily. 

Compost worms, however, seem able to stomach nearly anything grown from the ground. As reported in the Nature Communications journal, “the earthworm’s gut contains a suite of molecules that neutralize the polyphenols that give plants their colour, serve as antioxidants and discourage many ravenous grazers.” Amazing. 

Yet, there are naturally occurring plant compounds that even keep worms away. These are the ones that we, as red wiggler stewards, must be diligent to avoid. 

Some, like potato peels, may surprise you. Potatoes, along with eggplants, peppers, and tomatoes, come from the nightshade family. All nightshades produce solanine, saponins, and atropine-like toxins. 

Another toxic plant found growing in gardens throughout the world is the chrysanthemum. These plants contain pyrethrin, a natural defense against insects. Almost immediately upon contact with this compound, an insect dies from a form of paralysis. Worms fare no better. 

Other garden plants to steer clear of include leaves of the neem tree, eucalyptus, garlic, onion, citrus peels, and hot peppers. Instead of throwing these to the worms, why not blend them up, add some water, and make your own natural insecticide!?

Man-Made Toxins on the Rise

You know, I appreciate a nice, natural pest deterrent as much as the next gal. There are so many creative and effective methods. What I can’t wrap my mind around though is the vast amount of dangerous poisons sold to do these jobs in our homes and gardens. 

Do you or your neighbor use chemical lawn fertilizer, fog for mosquitoes, put out bait for rodents, or have a PVC hose? Each of these contributes to toxins in your environment. Yes, even cocoa bean mulch, natural but processed, is loaded with caffeine and theobromine. Both are insecticides to keep out of the worm bin.

As we consume and discard toxic products, nature’s delicate balance is thrown off. Wind and rain distribute these compounds far and wide, introducing them to eco-systems (kitchen garden/worm bin) they were never intended for.

Avoiding Toxic Relationships with Kitchen Scraps

One more unfortunate road leads to toxins in the worm bin. It happens when our tasty leftovers overwhelm the bin with salt, acid, or begin to ferment.

The problem with salt is that it burns delicate worm skin in relatively high concentrations, leading to death. Without precautions, it takes only months for a bin to become too salty. It happens with both naturally occurring salts, as well as those added as preservatives and flavor enhancers.

Acidic foods also burn the skin and leave worms without something good to eat. 

Being overfed, on the other hand, is problematic as well. When a worm herd can’t eat all they’re given, that food often begins to ferment, causing toxic gasses to accumulate. 

Toxins Troubleshooting

Wow, this all sounds scary and unavoidable, doesn’t it? But really, it’s not that bad. 

Conditions in your worm bin depend on the food and water you add and the frequency of your harvests. But thankfully, we have some reliable safeguards for you to keep things in order.

1. Remove the Offender

If something smells bad, it probably is. Just pull it right out of the bin and compost it. If it’s everywhere, move on to #3.

2. Rinse and Repeat

Wet food isn’t gross to worms. Go ahead and rinse food scraps to remove salt, vinegar, oil, and anything else added in preparation.

3. The Periodic Pour-Over

Shower your red wigglers’ food and bedding with clean water- right in the bin. It will wash accumulated salts and sludge right out. Make sure you have adequate drainage first!

4. Start Low and Slow

Any new material you want to add to the bin should always be given a trial first. Add just a bit in a corner and see how your herd reacts. Add more once you are sure the worms have no adverse reaction. 

5. Dual-Probe Meter

Of course, your trusty pH meter will be useful in assuring controlled acidity. And a moisture meter will let you know if you need to add water. 

The Bottom Line

Now, half your battle has already been won. You know what’s out there, how to find it, avoid it, and get rid of it too.

But just because you know it’s there though doesn’t mean you are off the hook. It still means you’re better off composting your prized, black-gold fertilized tomato plants in your hot compost rather than in the worm bin. The other nightshades may not be as harmful.

And remember, that’s not enough when it comes to salt! You have to harvest your worm compost regularly or rinse often to keep levels safe.

For the very best in healthy-living, worm accommodations, opt for your own custom-built stacked tray-style worm bin for showers and pour-overs. These worm towers are the very best toxin avoider/eliminator because of their perforated trays and catch basin at the bottom. Together they let the water flow through without ever losing a drop of that nutritious leachate.

No matter what, enjoy your worm herd this month! And stay tuned for next time when we’ll discuss a unique and valuable talent our red wigglers are prized for the world over!

Readers Comments (29)

  1. Recently a lot of my worms seem to be up on the lid, as Iam fairly new to worm farming I wonder what I am doing or not doing correctly. Many thanks for a great news letter. Graeme

    • I have read that worms can be sensitive to atmospheric change of pressure. My worms has a tendancy to gather there the day before a thunderstorm.

      • Normand, that’s so cool. I’ve known animals to respond to atmospheric pressure, but haven’t seen this myself. Anyone else ever seen their worms huddle before a storm? I’d love to see a picture! I’ll be on the lookout with mine!

        • Mine have all been above ground recently. We just had a temperature switch fro high seventies to low fifties.

          Also, worms try to escape if there’s too much water in the bin. Extra water can very easily go unnoticed if your lowed vent holes are a little higher than the very lowest part of the INSIDE of your bin. Or if you try to go without vent holes or a drain on the bottom. If that’s happened, just put dry bedding in the wet area to soak it up, and add more still. And consider putting new vents and or a drain in.

          Mine haven’t tried to escape since I put the extra bedding in and was more careful with the water.

          Personally, I think if yours are on the lid, away from the food, they’re apt to be escaping than they are reacting to air pressure changes. Mine have been reacting to air pressure changes by hanging out at the top layer of soil rather than further down. When they were escaping they were climbing up the sides of the tub, well above the soil. That’s what yours had to have done, unless your bin is really full.

          Also, are you covering the bin with lid the bid came with? Because even if you don’t close it securely, I don’t think they’ll get enough oxygen than way. Some of those bacteria and all of the visible organisms in their need more oxygen, unless you’ve put big enough holes in it. And the lid may not enough air for evaporation?

          Regardless, we should both have the right ventilation and drainage and lid if you don’t. I know I don’t. Worms have been fine somehow. Just bought a new bin because I’m out of room now.

          Oh. And I’m just using aluminum foil, smaller than the bedding surface area, with hole in it, to cover my bin. No smell because I bury most everything but the pond plants they are eating now. It is in the basement so that helps with aesthetics.

          I don’t mean too sound bossy. I’m just sharing what I have experienced and done. I’ve been at this for four years, but without real effort at all. So more experienced individuals, please show me the way, too, if I’m messing up.

    • Recently a lot of my worms seem to be up on the lid, as Iam fairly new to worm farming I wonder what I am doing or not doing correctly. Many thanks for a great news letter. Graeme

      • Graeme, when a new event changes the conditions of the bin our worms are happy to show us that they aren’t into it- by trying to escape. It is possible that your worms aren’t diggin’ whatever’s going on in their bedding. Too acidic, dry, hot? It could be almost anything, but I bet you’re the best one to know what’s new in the bin. Any hunches?

        • Depending on your oxygen content oh, you may want to increase air flow. I know when I started, my events weren’t big enough and when I sealed my lid my worms came to the surface to breathe. I increased my oxygen intake and they’re happy as worms!

    • I find that they usually don’t have enough brown material when they do this, it is too wet, or there is food in the bin that they do NOT like. I search out any food that smells bad or looks moldy- this means they aren’t eating it AND it’s fermenting. If it’s too wet, I add paper and cardboard.

    • Hendrik du Plessis May 5, 2021 @ 1:30 pm

      I had the same problem and drilled more air holes in the bin; that took care of the problem

  2. Until I read this months newsletter, I did not know that potatoes peels and garlic and onions were toxic to my herd!. I put garlic chives in the bin when I fed potato peels and onion shins. Will this wipe out my bin? I have tried to get the left overs out of the bin but they seem to be all eaten. Also can you over feed a bin? if you have a large bin with over 1000 worms, and it is over 4 months old, how much should you feed? thanx for the assistance.

    • Hi Ray! The worm bin is an amazing place. Inside there are so many forces at work. We often talk about the bacteria, but there are fungi in there too who eat up the stuff our worms can’t. Amazing right? The way a bin reacts to whatever you add will depend on how large and established it is, and which eaters are most prevalent- bacteria, fungus, insects, worms, etc. , along with temp and moisture levels. So, a bin with over 1000 worms and just over 4 months old is likely not too huge yet. That just means you have a little less wiggle room for now. So, if we assume that 1000 worms is about equal to one pound, or 2 cups worth, you should feed them half that amount each day. One cup, or one pound of moist food. Another good way to know is just to feed them whenever you see no more of their last feeding remains. Yes, you can overfeed a bin. You’ll usually know it’s happened if you have stagnant moisture, fermenting food, or a bad smell. Best to you!

  3. Hello. I live in zone 8b, and this is my first year keeping a worm bin. I have two bins at present, but I plan to add more in the future. My question is two-fold. What happens to my five thousand red wigglers when winter hits? And Would the worms prefer to be dumped, and set free in two of my new raised beds (along with plenty of good food) to work my soil through the cold stretch. My plan is to cover the beds, and line both on bottom, top, and sides with several layers of newspaper.

    • Hi James in 8b. ( : Answer 1: When winter hits, how cold are we talking? I’m thinking that you don’t see much below 15 degrees. In that case, if you are composting with specifically red wigglers, who do not bury themselves for protection, it’s best to keep them in their bin. Especially if you have a fairly large and well-established situation. You can insulate the bin, or bring it in if possible. The center of your worm compost should not freeze if you can wrap it all up and protect it well. The worms will slow down and stop working during winter but will “wake up” again when the weather changes in spring. Their cocoons will pop out a whole new generation come spring too!

  4. Christa Grobbelaar September 3, 2020 @ 4:45 am

    I have had my worms for 3 yrs now. Started out with the whole kit bought from a commercial farm. First year they multiplied like crazy,but I found the compost very soggy, and worms escaping. I had a thermometer in the soil and the temperature was fine. I bought another tower and split them up. Same story,and many found the way past the excluding screen into the wee bin. They were housed in a building in the garden. Often I found the floor of the room covered in thick layers of dead or dying worms. We then cut 200 ltr oil drums vertically, placed them on trestles and filled them partially with coco peat. Making sure for drainage on the bottom. Re housed the worms,covered each drum with a blanket. On top a ceiling board of polistyrene, covered by a sheet of plastic to keep the rain out. In winter I added a plastic sheet for each drum, another dogs blanket, and they survived minus 9 for weeks. My worms are fat and red ,multiplied Even in winter,and the compost lovely black and loose. I don’t get any pee, but never did in any case,there were too many dead worms in it. I now have drums full of happy worms

    • Oh! That sounds amazing! I love a good worm composting success story! The only thing that concerns me is the worm escape that you’ve experienced. And I have one little thought on that because of the cocopeat. Is that a blend of coir and moss? Coco coir is way acidic- too acidic in fact. Which may be why they were trying to escape, or also why you may have had lots of dead worms and much moisture in the compost. But here we have an excellent example of being able to successfully keep worms outside throughout the worst of winter. Thanks for sharing your method! Are your drums in the structure or just right outside now? And do you have an easy way to harvest those bad boys?

  5. This article says that tomatoes (potatoes, eggplants, etc) are toxic to worms, yet I have your kit and the “what to feed your worms” magnet lists tomatoes as “ideal foods”. Which one is correct, or did I misread the article?

    Also, this article says caffeine is toxic to worms, but reading other articles and comments on this site, they say that coffee grounds are great for composting and that the worms even like a little pick-me-up. Which is correct?

    Thanks for all the info! We’re very new to worms composting — I’m having my kids do it this year as part of their ecology unit.

    • First of all, awesome! I’m so glad you are pulling vermicomposting into your kids’ learning. They’ll use what they learn with this forever!

      Okay, so some clarification. Sorry to confuse you. Plants of the nightshade family do have toxins which are in HIGHER concentrations in the body/roots of the plant than in the fruits. Those (plant stems, leaves, etc.) are likely best to leave out. That being said, I have always thrown old tomatoes in the bin- never all by themselves because they are also very acidic, but the fruits aren’t the worst when they are all mixed in with other things.

      And as for caffeine- Remember, FRESH coffee grounds and USED coffee grounds are going to bring different things to the bin. USED grounds- go for it- the levels of acid and caffeine are way reduced in comparison to FRESH which is too much for worms.

      • Awesome! Thank you for the clarifications! Our worms get used coffee grounds, the stem/base of tomatoes that we slice for sandwiches, and bad spots from potatoes we’re baking. Sounds like I’m on the right track 🙂

    • I’ve been raising worms indoor and out for over 40 years. A long long time. Potatoes, whole potatoes and peels have always been added to my bin with no problems at all and in the summer when my garden is at its peak, tomatoes are often the main food source. There is absolutely no truth that the worms can’t have either. Even chrysanthemums will not kill red wigglers. I always deadhead mine and toss their dead heads in the worm bins and quite often I found seedlings sprout up. Never had any worm decline. People don’t realize that worms don’t eat what we put in the bin. bacteria, fungi, mold, microorganisms devour it and the worms eat those things. They have a fascinating book on the topic. No need to fear these things

  6. I’d really like to see some scientific data to support your claims. All of them. I have had experiences much different than what is speculated here.
    I don’t think you’re giving Mother Nature near enough credit. <

    • Hi Wayne! I appreciate your concern. And I agree, I should have some more scientific data to support my claims. I’ll keep that in mind as I move forward. Nothing I say however comes out of nowhere. Generally, I’m sharing with you the culmination of experience plus research. More of the same will always be better, so I’m really excited to hear if your experiences with compost worms have been different! Was there anything in particular that stood out to you that you were especially curious about? In my opinion, worm composting is so great because of how very many variations and methods work well. I certainly don’t want to take any credit away from “Mother Nature”, our finest and most wise teacher.

  7. I read today that inkjet ink, for the home printer has fairly high levels of ethylene glycol (super poison) and alcohol. I have a lot of the paper, but reluctant to use.

    • Hi Ed. Thanks for bringing that up. I’ve done some digging on this issue in the past. It’s important to remember how much ink goes into any particular sheet of paper. In the grand scheme of things, it’s very small. Also, we don’t know that chemicals affect worms as they would us. We do know that the worms don’t seem to mind printed paper as a bedding material. They don’t avoid it or seem sick from having it in there. However, knowing there are toxins of any sort gives us a reason to be extra cautious. So, there’s a pretty simple fix. After shredding your printed paper, give it a good soak or rinse and then squeeze out all that water. Down the drain will go any of the water-soluble chemicals that are released from the paper. Mix your paper shredding bedding into other bedding materials to further reduce the chemical load in any one place. Ta-da! The worms love that stuff!

  8. Tracy Cunningham November 1, 2020 @ 8:02 am

    I read that they do that for survival so they
    do not drown.

  9. I put chrysanthemums in my bin about 6 hours ago [hits palm to face]. After reading this article, I quickly removed any petals of it I could find. Is there anything else I should do to avoid immediate death from paralysis?? [hits palm to face again]

  10. Hendrik du Plessis May 5, 2021 @ 1:32 pm

    I had the same problem and drilled more air holes in the bin; that took care of the problem

  11. “”These worm towers are the very best toxin avoider/eliminator because of their perforated trays and catch basin at the bottom. Together they let the water flow through without ever losing a drop of that nutritious leachate.””

    I’m rather confused. You suggested to “rinse” the worm bin to get rid of toxins and yet you called leachate “nutritious”. Isn’t it risky to use leachate?

    Today, I also came across a mention of The Squirm Firm Worm Factory 360 in an article by Nora Held from Backyard Style (July 11, 20212) in which leachate is considered worm tea. From what I have “researched” so far, you need to “brew” worm compost to get worm tea, there are even recipes for it.

    • Hi Sue,

      Leachate is “nutritious” in the sense that it contains so many nutrients that can be helpful in making your soil productive. But the problem with leachate is that all of the materials in the worm bin contribute to the runoff, even those that worms have not yet processed. Because of this, the waste from the unprocessed materials can lead to the presence of pathogens and rot fungi in the leachate. As such, caution is highly recommended when using undiluted leachate. The USDA recommends that you allow at least 3 or 4 months between the application of pure leachate to the soil and harvesting of the crops.

      Worm compost tea, on the other hand, is brewed directly from finished worm compost. With this, the dangers of pathogens and rot fungi are minimized. Check out our blog post here about worm tea for more information:


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