80/20 Vermicomposting

In 1896, an Italian economist named Vilfredo Pareto published a paper demonstrating that about 80% of the land was owned by 20% of the population in Italy. This concept eventually evolved into what we now known as the “Pareto Principle” or the “80/20 Rule”.

The basic idea is that 80% of the effects come from 20% of the causes…80% of the results come from 20% of the people/methods, and so on.

This 80/20 ratio has been found to (at least roughly) apply to countless different areas of business, life, and the natural world.

See where I am going with this?

Yup…it definitely applies to vermicomposting as well.

That being said, don’t get hung up on the exact proportions – the key thing to remember is that…

Most of your vermicomposting success comes from mastering relatively few principles/methods. Said another way, it’s really only a handful of factors that have the greatest impact on the effectiveness on the vermicomposting process.

At the heart of our “vermicomposting engine” are the composting worms and the aerobic microorganisms that are so critical for helping to make things happen. So rule number one of 80/20 Vermicomposting is to absolutely make sure you are always doing your best to serve the needs of the worms and the microbes.

  • Don’t focus on how much waste you need/want to process.
  • Don’t daydream about the heaps of incredible worm castings your system is going to produce.

If you want to obsess about something, obsess about meeting the needs of your worms and obsess about avoiding the stuff that can harm or kill them!(from here on out any time I say “worms” it can be assumed that includes the beneficial aerobic microbes as well)

I am constantly amazed by the number of people who seem to forget there are worms involved at all – let alone take the time to really understand their needs!

Speaking of meeting needs…

I think this is a good time to introduce what I refer to as the “THRIVE/ALIVE Spectrum”. I originally came up with this concept to as a way for people to remember the temperature ranges needed in order to keep composting worms ALIVE, and the even-narrower range at which they will THRIVE. But, I feel it is useful for just about anything relating to caring for our worms, and the vermicomposting process in general.

For your viewing pleasure, I’ve included a super-fancy (lol) diagram – drawn on an old shipping notice – to illustrate the concept. If you want to see a bigger version just click the image (but not the “Pin it” button)

Remember “Rule #1 of 80/20 Vermicomposting”?

You don’t talk about 80/20 Vermicomposting…

Sorry – wrong club

[OK…goofball antics out of my system…CHECK!]

Rule #1 is that you should do your best to serve the needs of the worms and microbes.

Absolute BARE MINIMUM version of “serving their needs” is keeping the damn things alive. Agreed?

No worms. No vermicomposting. It’s as simple as that.

But I think it’s safe to say that most of us want more from vermicomposting than to simply keep a bunch of worms alive!

As such…

Rule #2 of 80/20 Vermicomposting (which supports Rule #1) – Always, Be, Optimizing (ABO)

“Optimization” is yet another concept I started writing/talking about in reference to one specific thing – optimizing food materials – but like the THRIVE/ALIVE concept, it can be applied to pretty well everything.

Optimization simply means providing the worms with the materials and conditions they need to THRIVE.

I know a lot of people tend to associate “optimization” with “lots of time/effort” or “hassle” – but it doesn’t need to be that way.

The more variables you can control, the easier it’s going be (so yes, those of you who need to vermicompost outdoors will have a more challenging time keeping things optimized), but there are still lots of ways to ‘always be optimizing’, without spending all your time fussing and fiddling!

On that note, it is now time to look at what I call “The BIG 3”.

If there is an “80/20 of 80/20 Vermicomposting”, this very well may be it!

  1. Aeration/Moisture Balance
  2. Food/Habitat Balance
  3. Temperature
  4. (“Cold/Hot Balance”?…haha)

If you are a worm farming professional (or at least a seasoned veteran) already, you likely march to the beat of a different drum and already know what things you really need to zone in on.

But for everyone else, (especially those who are fairly new to vermicomposting), getting these 3 things right can virtually guarantee your success!

Let’s look at each in a bit more detail

Aeration/Moisture Balance

Composting worms need moist conditions to thrive. They actually love it really wet…but the problem is that they also require oxygen (and naturally, so do the aerobic microbes that are so vital to the process). Water only holds about 10% of the oxygen of air…at the best of times (when it is cold, clean, and vigorously aerated).

Water that’s loaded with organic compounds and microbes – often quite warm – won’t be able to hold much oxygen in comparison, so the gas will need to be constantly replenished – otherwise anaerobic conditions will set in.

As an 80/20 vermicomposter (someone who wants to help the worms THRIVE), the trick is to provide the worms with the best of both worlds as much as possible. Moist-yet-well-oxygenated conditions can make a huge difference in terms of helping to guarantee our success.

People in composting circles often talk about moisture levels in the range of “wrung-out sponge”, and these recommendations have found their way into the vermicomposting world as well.

In some ways I am happy about this – since I would much rather see a new vermicomposter end up with a slighly “too dry” system than a sloppy, swampy system – but the worms themselves would likely prefer higher moisture levels.

Luckily, we don’t really need fancy equipment to measure the Aeration/Moisture Balance – a pretty basic look, feel, and smell test should tell us if we’re on the right track. If it looks and feels pretty moist, smells earthy (or there isn’t much of a smell), and the worms seem healthy and active, we are on the right track.

NOTE: Depending on the types of foods you add (regardless of whether they are optimized or not), there are almost certainly going to be times when you get some funky wafts coming up from the system. Cruciferous vegetables, for example, produce smelly sulfer compounds that get released as they break down. Aside from that – there are almost always going to be some anaerobic zones. The good news is that when you optimize materials and conditions, these types of smells (if they occur at all) tend to be very short-lived.

If everything looks really wet (probably don’t even need to feel it in this case), and there are foul smells coming from the system (worms themselves may or may not be in distress, depending on the nature of the situation), it means you should add a bunch of dry absorbent bedding and increase air flow (likely a lot).

Food/Habitat Balance

This can be closely related to the Aeration/Moisture Balance – and in fact, all of the “BIG 3” are intertwined, having a potentially-major impact on one another in different situations.

In my experience, new vermicomposters tend to obsess a LOT more about worm “food” than worm “habitat”. I think just about every newbie worm bin I’ve looked at has been woefully “under-bedded” (yep, I think I just made that term up).

Yes there are some (seemingly magical) situations where food and bedding become ONE, in true zen-like fashion (eg. aged bedded manure), but most of the time they should be treated as separate components that need to be balanced.

It’s important to note that the Food/Habitat Balance can mean different things at different times during the vermicomposting timeline. Early on, I would urge you to put most of your focus on stable, carbon-rich – ideally bulky and absorbent – bedding materials, with a much smaller emphasis on food. As the process progresses (now that there is lots of bedding already in there and it’s fairly slow to break down), it’s time to put more emphasis on (hopefully optimized) feeding since you’ve already established a safe habitat.

On the tail end of the process (as we wind down towards harvesting) it tends to be more about letting the worms work through as much of the remaining (unprocessed) material as they can. The habitat quality (and overall balance) should still be good, simply because you’ve taken good care of the system all the way along.

Both food and bedding are technically food.
(I’ll let you chew on that one for a minute – haha)

One just takes a fair bit longer to get processed (and also happens to offer much better habitat value). If you think about it in terms of “reactivity” or “stability”, the materials we usually think of as foods tend to be quite reactive/unstable – they can start to decompose relatively quickly, and during the decomposition process can release liquids and gases that can potentially harm the worms.

Bedding (and “living materials”) will be a lot less reactive and a lot more stable – so they can provide a sort of “buffer zone” between the decomposing wastes and the worms…and they even help to “clean” things up, soaking up liquids and converting reactive compounds into less reactive compounds via microbial action etc.

I realize that probably sounds more like a chemistry lesson than vermicomposting – lol – but hopefully you at least see what I am getting at!


If there is one factor that is unbelievably-important-yet-so-many-people-seem-to-ignore…it would have to be temperature!

The most tolerant of the composting worms tend to have a survival (ALIVE) range in the ballpark of 0 C – 34 C (32 F to 94 F), and an optimal (THRIVE) range of somewhere between 20 C and 30 C (68 F and 86 F).

Give or take…and yes there are legendary cases of extreme heat/cold tolerance floating around the interwebs. But they are still good guidelines (and they are backed by academic research)

I am constantly amazed by the number of emails I get from people wondering why their worms “aren’t eating anything”, or why it is “taking so long” for anything to happen (in the bin sitting out in an uheated garage in February) etc etc…and on the flipside, from people wondering why their worms are all dead, after they put them outside…in a plastic bin…in direct sunlight…in 100 F weather!

Ok ok – I am going a little overboard here…but there definitely seems to be a lot of misunderstanding, or hoping-for-the-best attitudes, when it comes to temperature!

Vermicomposting outdoors – as amazing and productive as it can be, is obviously going to create some temperature challenges for even the most experienced among us. So rest assured, I completely understand that this isn’t always something we can get “perfect”. Heck, there may even be times/places where vermicomposting outside is flat-out impossible (perhaps a good time to remind people about my recent “Insurance Bin” article).

Apart from climate-related heat (ambient heat), microbial heating can be another one to watch for (and can be a real thorn in your side if you are already trying to deal with hot air temps). The silver-lining associated with that one is that it can actually be really helpful once ambient temps fall into the cool-to-cold range.

So that’s the BIG 3 in a nutshell. If you can get a good handle on theses three areas, vermicomposting will start to feel a lot “easier”, and you’ll likely stop obsessing about a million other little things.

Any time you assess your systems, try to get into the habit of asking yourself:

How is the Aeration/Moisture balance?
How is the Food/Habitat balance?
How is the Temperature?

80/20 Vermicomposting is really about getting the right things right!

Save time/effort. Get better results. It’s as simple as that.

Is this a topic that could be fleshed out a LOT more in order to gain a full understanding of it? You betcha!

SO…if you found this article interesting, please make sure you are signed up for the Red Worm Composting Newsletter, where I will be sharing info/updates relating to this topic, and a whole lot more!

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    • Karl
    • April 12, 2018

    This post really came in handy today. Just over the weekend I found out I lost all of my native worms I had in a tote outside facing the east in the morning till after noon. I now believe I killed them by too much heat.

    My millipede compost bin right beside it is doing fine, but I think they can take the heat much better.

    Thanks for the post.


    • Dave Pawson
    • April 13, 2018

    Aeration + Moisture balance. Not easy in an outside (large) bin.
    Compost supposedly requires compression, which goes against your aeration requirement?
    I guess this is why I only see worms in the top few inches of my ‘bin’
    (1m cube slats)

    • Bentley
    • April 13, 2018

    Hey Dave – thanks for chiming in!
    Where does your “compost needs compression” comment come from? I definitely agree with the statement that aeration/moisture balance can be tricky outside (as can temperature, of course), but in my mind it would usually relate to the type of system being used. I use a lot of in-ground systems – naturally it is going to be a bit more challenging to keep them from going anaerobic – and this highlights the importance of actually loosening things up (not compressing) via bulky habitat materials. The good news is you definitely don’t need to get things “perfect” by any means – and not everyone has the same goals (or level of patience – haha). But with a constant eye for how you might tweak things for the worms benefit, you may start to see a more effective vermicomposting process developing over time.

    • Dave Pawson
    • April 13, 2018

    From …. old wives tales? (Failed to find a source. I had ‘cover, compress… and keep wet – another C).
    I am physically unable to turn a cubic metre every n weeks…
    Likely why I see the activity on the top?
    I do add wet cardboard boxes (fairly regularly). Also kitchen green waste.

    More on ‘tweaking’ things please Bentley!

    • Bentley
    • April 17, 2018

    KARL – apologies, you ended up lost in the shuffle!
    When you say “native worms” – do you mean composting worms from your region. Or are you referring to soil/garden worms.
    Millipede compost bin? That sounds interesting!

    DAVE – Sorry for the delay. No worries about the source – I was just curious more than anything. One of the great things about worm composting is that the worms basically do the mixing/churning for you so no need to turn the way you would with a hot compost heap. As long as you are adding bulky materials like shredded cardboard along with the more typical “food” materials things should work out well. Does the bin have side vents at all? My backyard composters (which work very well for vermicomposting) have quite a bit of ventilation, which definitely helps a lot.

    • K. Romer
    • April 22, 2018

    I have been vermicomposting for years, but recently learned something new via an accident. A visiting friend left behind her farina (similar to Cream of Wheat). As I don’t eat this, I decided to use it in making some worm chow instead of oats and cornmeal. I simply blended egg shells and the farina. I sprinkled some on top of my african nightcrawler bin adding a top dressing of damp leaf mold. This is something I often do with the regular worm chow with no problems and the worms really go crazy for it and fatten up. Well next morning I find the worms all trying to escape the bin. Checked the temp and the bin was hot (100+!). Mistakenly thought this was due to the leaves not being composted enough. Moved these worms to my backup bin, which was doing well. A couple of days later I sprinkled some of the farina worm chow on the backup bin and it heated way up (110!!). Don’t know why, but the farina apparently had this affect, while the regular worm chow made with corn meal, egg shells and oats doesn’t. I nearly lost all my worms, but managed to save about half of them. Just goes to show there’s always something new to learn, and you can never be too careful when trying out new things to add to the worm bin.

    • Bentley
    • April 23, 2018

    K – that is very interesting. Thanks for sharing. It is funny how certain materials can really send the heat skyrocketing. Coffee grounds seem to have a similar effect in my experience.
    Where a lot of people go wrong is they make these changes and then they don’t keep a close eye on the system (eg load up the system then go away for vacation etc)
    Glad you were on top of it and able to save the worms!

    • Karl
    • April 23, 2018

    The worms are Florida Native worms sold by a fellow in Tampa. He sells them for composting and fishing. They were all fairly large (about 4mm diameter and 3 – 5 inches long). He’s been doing so for years.

    My millipede bin I have had for around two years now. A lot of people complain about the millipede, but I started collecting them and put them in a bin with leaves, bark and such. I also feed them banana peels and carrots from my wife’s juicing. I have harvested millicompost 3 times and have a 27 gallon tote about 3/4 full. I have read a study that says millicompost is better than vermacompost.

    The millipedes have done well in the heat and cold here (relatively speaking) and they keep propagating in the tote. I have used Mahogany nut leaves and a tree from my neighbors, but they are all gone now due to Hurricane Irma. I think I will have to go to Native Oak leaves now.

    • Bentley
    • April 23, 2018

    Very interesting, Karl – how big are these millipedes? I am guessing they’d be bigger than the ones we get around here. If you know the article (etc) you read that said they might make a better compost than worms I would love to read that as well.

    • Karl
    • April 24, 2018

    The millipedes are usually around 1-2″ long when full grown. There are two types we get here in most of Florida: Rusty and the Yellow Banded. I have almost all the Rusty Millipede. I have had the Yellow Banded, but very few.

    The study I’m referencing is here:


    I can send you some pics if you are further interested.


    • Patty
    • April 30, 2018

    I now have access to both chicken and goat manure. My Worm Inn is inside my house (and I don’t have a basement! Lol)
    Are there likely pest or odor problems if these are added to an indoor Worm Inn? Of course that would be after properly aging the manure. And, is there any advantage to adding manure, rather than only bedding and food waste? Thank you.

    • Bentley
    • May 1, 2018

    KARL – thanks for the additional information. I might try setting up a system with our smaller millipedes (maybe combined with isopods) and see what happens.
    PATTY – I would be very careful about chicken manure. It is definitely a different beast altogether. But aged goat manure (especially if previously mixed with bedding materials) would likely be excellent. And if it has been sitting outside for a while you may find that it comes with a really beneficial ecosystem that will help you keep things in balance. That is what I have found when adding well aged horse manure to indoor systems. I would still include moistened bedding (like shredded cardboard) and maybe still some food waste – but you probably wouldn’t really need to if you didn’t want to. Just make sure the manure doesn’t have a strong manure/ammonia odor (sign it hasn’t aged enough)

    • Charlotte E Flock
    • May 21, 2019

    I will be having a submerge subpod in the ground. I am really hoping it will do will. Thanks for all the tips. I need to find a thermometer. To watch the heat for awhile.

    • Brad Boswell
    • June 16, 2019

    I’m going to try and start a worm farm in a old freezer that doesn’t work in my garage I live in southeast Arizona concerned about the Heat has anyone tried using ice bottles to keep the heat down?

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