Composting In The City Apartment With A Worm Bin

Last updated on October 23rd, 2023 at 08:24 pm

With a worm bin, you can compost even in a city apartment. This saves emissions because no waste has to be transported.

Composting In The City Apartment With A Worm Bin

What Exactly is a Worm Box? And Does It Not Stink??

A worm bin is also called a worm farm or worm compst, depending on its purpose. Anglers also often keep worm boxes as worm farms to always have bait. The focus is not on composting kitchen waste, but simply keeping (“hältern” called) the worms as bait.

But I actually always speak of worm box, because as the name suggests, it is a box in which worms live. Glad we got that cleared up 😜. The worms inside look almost like smaller earthworms, but they are compost worms.

They eat the parts of the clippings that decompose by microorganisms, as well as paper and cardboard, and the digested stuff is then valuable fertilizer that you can use for your plants. However, since we do not have a green thumb, we will give the fertilizer to the dear Vany, who had written this nice guest post once for me and has a garden.

Well, it is a bit more complex than that. It is actually a whole ecosystem in a box! That’s why some schools have worm boxes with a glass pane inside, so that children can watch the worms at work and directly see the different layers for environmental education. So that the worms are protected from the light there is even a curtain in front of the pane 😆. Almost like being in the cinema 😜!

The composting in it runs odorless, because oxygen gets to it. So unlike organic waste or your kitchen garbage can, the worm garbage can doesn’t smell. Ours smells, depending on what we just put in it, like coffee, cabbage or, like right now, like mowed lawn, because we have weeds and grass from the balcony in it. Otherwise, it smells like wet leaves, so slightly musty. If your worm bin stinks, then something has gone very wrong…

Who is a Worm Bin for?

A worm garbage can is especially interesting for city kids like me who don’t have a garden and/or an organic waste garbage can in their apartment building, but also for other people who not only want to dispose of their organic waste ecologically, but also want to upcycle it. Upcycling creates something more valuable from waste than before, and the worm hummus is a very valuable fertilizer, which is rather expensive in the shops.

But I Have a Bio Garbage Can, That’s Just as Eco, Isn’t It?

The bio garbage can is definitely already a cool thing, but unfortunately still not as ecological as composting yourself 😉.

For some cities, for example, setting up and collecting organic waste is not even worth it because less energy can be generated from the collected organic waste than the collection process consumes.

What we also often forget is that behind this there is a whole, huge logistical system that also has to be built and maintained. Extra vehicles have to be built and maintained for the collection of organic waste. Each new type of waste means that all the streets in the city have to be canvassed once more with a vehicle. Of course, the biogas plants where the biowaste goes also have to be built and maintained. That must be recovered first of all by the biowaste. In addition, biowaste is not turned into compost, but into energy, which is not recycling in the strict sense. What remains, however, is something beautiful again, namely potting soil 🌻.

All these energy- and resource-consuming items are eliminated when composting at home. Local it really does not go and is even an upcycling.

Composting In The City Apartment With A Worm Bin

Can Everything That Would Otherwise Go Into the Organic Waste Go in There?

No, unfortunately not. So no cooked food scraps, banana peels, meat or dairy products, because they go bad too quickly, and strong-smelling things like citrus, onions and garlic are unfortunately also spurned. The worms are raw food vegans, so to speak, and make exceptions only for tea and coffee grounds. Then there is still cardboard and paper purely for the balanced worm nutrition. But pssst: In small quantities come with us nevertheless banana peels (only organic peels, otherwise the pesticides in it kill the entire worm box!), citrus, onions and garlic purely, because our happily unhidden popping worm population eats already faster and more, than what we generate at kitchen waste at all, and as it says so well: “The hunger drives it down 😂”. In the vegan Café Corba here in Bochum, they even took pity on the little worms when I told them that and has already given me a few times coffee grounds, so that the poor things also get enough to eat 💚. But that is not really necessary. The population regulates itself according to the amount of food and the environment, i.e. they only multiply as much as there is food and remain constant at some point.

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Composting In The City Apartment With A Worm Bin

But also things like cotton, linen, used up Lufah sponges as well as the handle of bamboo toothbrushes (and depending on the manufacturer even the bristles) can be composted. Eggshells are supposed to be great for the worms, but as vegans we do not have them of course and had so far little ambition to scrounge them somewhere from others 😜. Instead, almost everything may pure, which accumulates with us so, hehe.

But remember: Nothing can be composted that still has life in it. So unroasted seeds and kernels sprout partly in the box 😉. We just cut them once before putting them in. Yes, I know, cruel, cruel 😜.


  • Dust and what you just sweep up or collect in the vacuum cleaner bag.
  • Hair
  • Finger and toe nails
  • Dead houseplants incl. soil (yes, we really don’t have a green thumb 🙈)
  • Nut shells (except from walnuts, because they can be toxic for plants)
  • Badly turned jam or preserves in small quantities
  • Dry dog, cat and fish food
  • Droppings from rodents and birds, but not from dogs and cats!
  • Burnt residue from a match
  • Real cork (not the plastic ones)

What Should Not Go Into the Worm Bin or the Organic Waste?

Bioplastics should not be placed in the organic waste or in the worm bin! The “biowaste bags” made of corn starch plastic and the like clog up the biogas plants because they would take more than five years to decompose even under the scalding hot conditions in these plants. And in the other waste, i.e. yellow bag and residual waste, bioplastics are simply treated like regular plastic and end up in waste incineration or “energy recovery”, i.e. they are also burned, only in coal-fired power plants or in factories’ own power plants. Glossy paper also belongs neither in organic waste nor in the compost.


    These boxes are mainly available in plastic, but are very beginner friendly and even fit under the sink, depending on the model. Here is a clear graphic that illustrates how they work well.

Basically, the “food” for the worms always comes on top and the worms just keep moving up to the new food, so that at some point you can take away the completely composted layer at the bottom. Since the liquid seeps down, there is a small tap at the bottom, with which you can tap the so-called “worm tea”, an excellent liquid fertilizer. Thus nothing can wet down.

However, when harvesting the compost you have to comb it again for worms, because because of the moisture usually still worms are in it. Here is a video where it is shown how this works:

Or just leave them in, they are good for plant soil 😉.

    This is the system we have. This is usually not so advised to beginners, because you can do more wrong than the vertical system, because without a tap at the bottom you have to keep track of the humidity of the box itself. We decided to go for it after all, because they are usually made of wood. Since my husband and I both have two left craftsman hands we had bought such a wooden box. But you can also build it yourself. I have linked instructions at the end of the article.

Horizontal worm bins have a two-chamber system with a grid in between. You fill your kitchen waste + paper and cardboard always in the one chamber, until it is full after about 1.5 years. Yes, you read correctly – one and a half years! That’s because 10 liters of kitchen waste will eventually add up to just a handful of compost. So when one chamber is full, you move on to the next. Eventually, the worms will have eaten and finished composting everything in the first chamber and will move through the grate to the second chamber. The first chamber is then left to dry out for another 3-4 months so that there are really no worms left in it (worms need moisture) and then you can simply shovel out the compost. And so you always change the chambers until after about 5-6 years the box is also through, because the (untreated) wood is of course also slowly worn by the worms.

Where Can I Get Compost Worms?

Unfortunately, I naive city kid don’t know anyone with a compost pile. So I tried to find someone who would give me compost worms through one of the local Facebook groups in our area. No such luck. So I ordered me some via Ebay for, I meant, 30-40 EUR 😂.

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Today I’m smarter and know that you can ask as a city person in allotment associations or urban gardening projects. They usually have one or more compost heaps somewhere, where you can take something if you ask nicely and a small donation is certainly always welcome.

Who lives in the country will surely find someone in the neighborhood with a compost heap or knows a horse farm nearby. Because where horse manure is, there are certainly compost worms, because this is their favorite food 😂…

Is Compost Worm the Same as Compost Worm? And Can’t I Just Go Collect Earthworms?

No, earthworms also compost, but firstly not as well, and secondly they stay in deeper layers of soil, i.e. they would die in a box with a closed bottom!

In general, you can go worm collecting outside even in rainy weather. There are different worm species that compost well and live in the upper layers of the soil (e.g. in the leaves). The only thing they have in common in these latitudes is that they are all red and smaller than earthworms. Earthworms tend to be elongated, pale, and pinkish to whitish.

There are also leaf worms sold as food in pet stores, they are also suitable and feel comfortable in the box as well. However, they do not compost quite as well as extra worms sold as compost worms and, as far as I know, they are sold in plastic boxes and cost quite a lot (about 50-100 pieces for 4 € or so). Who has patience, can grow from it very slowly but also a population.

Then there is Dendrobaena veneta, which is significantly larger than both species (but smaller than an earthworm) and is therefore popular with anglers as bait…. It eats a lot, so composts very well, but doesn’t reproduce that fast.

It is often recommended to put a mix of worms in the box. Then, over time, the species that best suits its own crate becomes established. By the way, in addition to the three compost worm species, we also used leaf worms and, depending on where we dig, we still find columns of the different worms after more than a year. With us, no species seems to have prevailed, and they share the food apparently quite happy 😊.

Set Up Worm Box

Tear paper and cardboard into strips about 3-4 cm wide and best to moisten beforehand (I had done this wrong in this picture and only sprayed in the box then, which was not enough).

… and mix again, if possible already bury a few snip waste in one place and best cover with a moistened hemp mat or dampened newspaper and leave alone for a few days so that the worms can recover from the stressful move.

What Else Do You Need To Consider?

The worms like it moist and dark. So every now and then something should be moistened with a spray bottle. I must confess, however, that I lack the patience for this and instead (but only since the box is full) water carefully. If it’s too wet (that is, starting to be more wet than damp) you can mix in strips of paper or cardboard. If you have a vertical worm bin, you can also just turn on the spigot at the bottom and let the excess liquid, worm tea, drain out. If it’s too dry just moisten it.

If one puts then Schnippelabfälle in, one should bury easily, so that fruit flies u.Ä. do not come well to it. Somewhere I had read that the ratio of cake waste to paper and cardboard should be 6:4. We also stick to this pi by thumb. At the end put a damp hemp mat or newspaper on it, so that everything stays nice and dark and damp and to keep in fruit flies brought in by e.g. fruit bowls.

Now and then a handful of stone meal, eggshells or a special worm-mineral mix from the specialized trade (packed in plastic, but sufficient for at least 3 years) ensure that the worms get enough minerals and continue to reproduce happily. Otherwise, the population may suddenly collapse out of nowhere after 2-3 years due to lack of nutrients.

These are the basics. Worm bin care is a complex subject, and you can get lost in it at times. We had read so much about it in the beginning and tried to keep in mind, and I can only say that by now we don’t do more than what was just listed here.

But remember: a newly created crate with a small worm population is more vulnerable!


  • Better too humid than too dry.
  • Better too little waste than too much – this is especially important in the beginning, when you still have a small population, because it is more susceptible, as I said. Guideline: 500 worms weigh about 300 g, because such a worm weighs less than 1 g on average. Since they can eat up to half of their own body weight per day, you should not put more than 150 g per day in the beginning, rather less, so that the box does not tip over due to rot, because the worms die faster from overfeeding than from underfeeding exactly for this reason!
  • The things should lie loosely, so that oxygen comes to it. This is important because otherwise rot and unpleasant odors will develop. Damp paper and/or cardboard help to keep things airy.
  • If something smells, find the spot and loosen it up there and mix in some damp paper or cardboard. If there is something really wrong, remove the culprit (fortunately this has not happened to us yet and should not happen if you have followed the points above).
  • Whenever we think about it, we add a handful of mineral mix from the worm shop (hihi). That is with us perhaps so 1x in the month?
  • Otherwise just leave it alone. So don’t constantly pick around in it, poke around, dig around, rummage to see how far something is already composted or shine a bright light into it. All this stresses the worms. Once a week, when putting in the clippings, lifting them more closely and seeing if it is still moist enough is enough.
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What About The Worm Box When I Go On Vacation?

It is no problem at all not to feed the worms for up to four weeks. Because, I like to say it again, they die from overfeeding rather than underfeeding. We were away for three weeks in March and when we came back our box was even more lively than before, because fasting and being left alone did them good. Of course, you should not leave them permanently without food. But times so for a vacation it is no problem.

Should you travel longer, you can find tips for precautions here.

My Worm Box Stinks

Then something is literally wrong. Reasons can be:

Quickly gammelnde things like banana peels, meat & dairy products or food scraps ➡️ in the case remove the culprits.
Not enough air could get to it because things were too close together in one spot ➡️ loosen and mix in damp paper and/or cardboard in that spot
Or it may have simply been overfed. The worms could not utilize all this fast enough and it starts to rot ➡️ remove these things from the worm bin as soon as possible. If that is already too late, because the whole box is already tilted, rescue the worms from it, dispose of the remaining contents and create a new box. None of this helps.

The Worms Are Out!

If that happens, then something is very wrong! They only do that when they really fear for their lives. Because outside the box it is bright and dry, and they would not take that on themselves, if it is not even worse inside. Reasons can be:

It’s too hot. This happened to us last year in summer when it was over 35 degrees. There are actually times isolated worms escaped. No wonder, they die when the temperature is permanently above 30 degrees. And they didn’t escape en masse, because the poor things were probably all already crawling around. So we couldn’t do much except pick them up and put them back in the box. Of course, if you have a cool basement, you can put the worm box in there.

It is too cold. If the worm bin is in the apartment, this can’t really happen. If it stands on the balcony, it should definitely be covered with a blanket as insulation in winter.

In the long run, too little food for a population that has grown too large. However, this also only happens when the worms hardly get any food over a long period of time (well over 4 weeks). Then they migrate to look for a better place to live. If they get something continuously, the population actually adapts to the environment.
Too much sprayed fruits and vegetables/non-organic banana peels. Pesticides kill the entire ecosystem including the important microorganisms. If the worms still make it, they will try to escape.
Too much citrus/onions/garlic. I said it before, the little things don’t like essential oils in the peel of citrus, or biting onions or garlic. It drives them away like vampires.


  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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