What Happens If You Don’t Monitor Moisture In The Worm Bin: Part 2

What happens if you don’t monitor moisture in the worm bin: Part 2

Which is more dangerous for a worm bin, to be too wet, or too dry? That sounds like a “Would You Rather?” kind of question. You might be able to bounce back from one or the other, but both put you in a bad situation.

Last month we got underwater with our compost worms. We focused on the too-wet end of the spectrum. Up close, we saw the devastation of unregulated moisture build-up. This month, we’re dialing back the humidity to see what happens when conditions lead to an arid worm bin instead.

You Didn’t Monitor the Moisture?

It can happen in many ways. And I’m not judging! I’ve experienced extremes in my own bins too. I’ve learned many unfortunate lessons with my worms, but still, accidents happen.

You know how it goes, you don’t feed enough juicy stuff, or add too much dry bedding. You forget the shadows change through the months and, oops, there they are, left in the sun. Please, tell me I’m not the only one!

Then there’s this one, the most dangerous of all, assuming you know it’s “fine”, so you simply neglect to measure the moisture in your worm bin.

It takes less than 5 seconds to check the water content of your worms’ bedding. But if forgotten or ignored for just a bit, you may be headed for disaster. But like most red wiggler care, the actual management of moisture is super simple once you know what compost worms need.

That’s why this month our focus is on the importance of monitoring worm bin moisture, and what happens if you don’t. By the time you finish this article, you’ll be set for year-round moisture maintenance. Using The Squirm Firm’s resources and troubleshooting tips, you’ll never find dried up worms again!

What’s the big deal?

When it comes down to it, a few seconds with a simple moisture meter is all it takes to be certain. Something close to 80% humidity puts your red wigglers right in the safe zone. Much above that and your worms end up with a swampy situation, as we discovered last month in Part 1.

This month we’re taking a look at the opposite effects. What happens when moisture levels drop below that 80% sweet spot? The hazards are just as dangerous but can happen even more quickly.

A Dry Worm Bin Leads To…

The Death of Beneficial Microorganisms

Like most living things, many of the aerobic bacteria living in a worm bin require hydration to live. As a worm bin dries out, the very helpful microscopic organisms inside become dehydrated. They then die off by the millions.

Those beneficial bacteria are the main reason we start new bins with a scoop of garden soil instead of sterilized potting soil. It’s in the living natural material outside where hard-working microbes multiply. Those bacteria are really important!

The End of Decomposition

Wonder what makes millions of healthy bacteria essential to worm composting?

It’s this. Without a thriving workforce of creatures to start the breakdown of organic matter in the bin, worms can’t eat much of what we serve. Eisenia fetida is a worm that can only suck food up. It can’t chew, per se.

With no teeth to grind with, worms rely on their bacteria friends to get things started and softened up. This is when decomposition begins. Once this is achieved the worms ingest both the bacteria and the nutrients inside them.

However, in a dry bin that whole process grinds to a halt. Fruits and vegetables dry up instead of breaking down and your compost operation stops.

Bedding Becomes an Impossible Food Source

Food becomes much more scarce when the worm’s bedding is no longer a supplemental source of nutrition. What was once an all-can-eat buffet becomes a dry and barren landscape.

Bedding dries from the top down, and the outside in. With very little left to suck up as food, worms have no choice but to re-consume what has already been composted. (Actually, an attractive prospect, being full of nutrients and able to retain water.)


Worms innately keep themselves where the bedding is most moist. The moisture within the tunnels they travel serves them well. It helps keep that mucus layer over their skin nice and slippery.

That thin wet barrier is what works somewhat as lungs for the worm. Through it, a worm takes in oxygen. From it, carbon dioxide comes out.

Without monitoring for proper moisture balance, the worm bin can get dangerously dry. When that happens, a worm’s fragile mucus layer is destroyed and breathing becomes impossible. These worms die of asphyxiation, or suffocation.

Worms Lose Moisture to the Bedding

As juicy worms slip through dry bedding, their moisture is sloughed off and drawn away. Dry organic matter causes small tears in the delicate skin making for even quicker dehydration.

Worms Cozy Up to Share and Conserve Moisture

Worms have an amazing “creature power.” In an effort to conserve moisture a colony of worms balls up in the face of a drought. They gather en mass and keep each other slippy.

The Search for a More Hospitable Environment

Another fancy trick that compost worms do involves some interesting group mentality. Remember that ball of worms trying to keep wet in the last point? Well, sometimes they will decide to make a run for it, and head out all at once.

Crusty Critters

But how far can thirsty worms travel into unknown territory? Outside of the confines of the worm bin humidity is generally far less than ideal. It doesn’t take long for the mucus layer to be depleted as it moves along rough dry ground. The unprotected worm quickly dehydrates and is left to shrivel.

A Halt in Population Growth

As I mentioned before, these guys will seek out better living conditions if necessary. When they are stressed and looking to relocate, reproduction slows. They know by nature that dry conditions won’t sustain the life of immature worms. Mating only resumes once living conditions are back to ideal.

How dry is too dry?

Is it possible to know just by looking? Sometimes, maybe. But that’s risky.

At nearly 90% water themselves, compost worms require a consistently humid environment. They can tolerate lesser amounts, but levels near 80% humidity are where they thrive.

Practically speaking, if you squeeze your vermicompost and it falls apart when you open your hand, you know it’s way too dry. But there’s a long dry road to get to that point too. Don’t wait until then to be sure!

Aren’t you curious to know where your worm compost falls along the 1 to 10 spectrum? Moisture levels can change by the day, or even the hour depending on your setup. Don’t chance it.

Go and See

For the cost of a couple of cups of coffee, a reliable gauge is all it takes. It’s definitely one of my favorite worm composting gadgets. …Especially since it is powered using the enzymes in soil for energy. It doesn’t even need batteries! You gotta love that!

If you don’t have your own moisture meter yet, it’s even more important you stay diligent. Give your bedding a squeeze once in a while, and be on the lookout for any of the dangers you learned about today.

I like that it’s super easy to use a probe meter. With a color-coded range from 1 to 10, a moisture probe reacts the moment it touches the soil. The pointer jumps to a reading and you know immediately how your worm compost is doing.

Keep one on hand and use it frequently. It’s the only sure-fire way to avoid what happens when you forget to manage moisture in the worm bin.

Most of all, happy worm composting!

Readers Comments (8)

  1. I add bedding (shredded newspaper, leaves, cardboard…they also get a worm meal and extra pulverized eggs) when feeding my worms and then spray and or add water. They are in a Worm Cafe in the garage. In Summer I place a frozen container inside the top tray and in Winter when the temperature drops, they get covered with old towels, etc. They seem to be happy. I do find that sometimes some like to congregate around the defrosted container so perhaps they are telling me they need more water???

  2. Hi I do not understand bedding. It is edible, but is it food? Does it have a purpose other than being eaten? If not eaten, wont it just be uneaten buried beneath the casings? I am using cardboard but mostly shredded newspaper saturated with cooked grains and vegetables. If they eat all the bedding is that a problem? Thanks

    • Hi Alan, really great questions. Your confusion makes sense. We use the term bedding to refer to basically all that the worms are living in. It is the compost along with everything else that hasn’t been eaten up yet. So when we add shredded paper, that is bedding. The accumulated organic material that is in the middle of processing is ALSO bedding. Its purpose is primarily to be the worms’ habitat along with serving as a source of food. In time we would assume that all bedding ends up being eaten by microbes or the worms. That’s why we continue to add dry brown materials to decomposing bedding. Does that clear it up for you? Happy to help if you have any more questions!

  3. Hi Francesca,

    Once you’ve determined that the moisture level is too high, what can you do to redirect and salvage the situation? Add more bedding? Wait it out? Scrap the whole bin and start over?

    How long do you have to save your wormy friends once you see the warning signs?

    • I wonder too. I had a neighbor give me a bucket with red wigglers and I am just now ordering the 360 worm bin. They are back ordered so it will be June before I can get one. I don’t know a lot about the worms but what I did do was put shredded paper into a larger bucket and then added some organic store bought dirt. I then took the bucket that had the red wigglers with some food scraps that I had added and turned it upside down into the other bucket. The bottom 1/8 of the bucket was wetter than I knew. I have tried not to add too much water to the bucket. Now I know. I figured that my turning it upside down into the larger bucket the wet area is going to seep down to the through layers. I hope it will be all right until I get a new worm bin. I do wish that he would address if there is a way to know how to reverse it. I still don’t even know exactly how to set up a worm bin but all the best in your endeavors.

    • Hi Jen- NO! Don’t scrap it! It depends on how high a moisture level you’re talking about. I’ve had an unfortunately high moisture situation in the past that was unsalvageable- but even that had usable compost and the makings of worm compost tea. So, if there’s still life in your bin- open it up, give it air, and yes, add a ton of dry shredded paper, cardboard, whatever! Leave it open and give it a gentle turn every so often to expose more of the moisture to air. Remember, the worms prefer wet to dry, the situation may be all better in just a day. Don’t give up!

  4. The first tray of my worm factory 360 is nearly full. The moisture meter reads 7-8 on a scale of 10. I have several layers of paper on the top of the bin. When I remove the lid, there is quite a bit of condensation on the under side of the lid and 20-30 worms as well. Is my bin too wet? The bedding seems almost too dry to me, but I’m concerned about the condensation. The bin is in the garage and the bin temperature is generally in the 60s. I thought if the worms were happy they wouldn’t be up on the lid. I would appreciate your advice.

  5. Hello Squirm Firm,
    I purchased my Worm Factory 360 about 1 1/2 years ago.
    My question is, why do the worms keep going all the way down to the very bottom, where the “tea” is accumulated?

    My setup is a top (feeding) tray, 3 (processing) trays below the top tray, then the very bottom bin where the “worm ladder” & drain are.

    I regularly feed them and I give them a healthy diet of veggies, some fruits, and sometimes corn meal and a little wheat flour, fine egg shells for calcium & digestion and an occasional bit of azomite rock dust to also aid in their digestion.

    In the top tray where I feed them, he PH is a steady 7 and the moisture is a steady 5.5 – 6, yet I CONTINUALLY have to fish the worms out of the bottom section and place them back into the feeding tray.

    Any ideas as to WHY they keep migrating all the way down to that bottom bin???

    Thank You Very Much,
    Ben N.


Leave a comment

Your email address will not be published.