Composting in our apartment : Worm composting

Pour lire en français, c’est par ici !

Today we’re discussing organic waste, rotten things and worms. Yes, I’m a glamourous kind of person 😉 Still there ? Let’s dive in worm composting !

.What the hell is that, you might be thinking. I was the same when I first heard about it about five years ago but now I can’t imagine going back to what it was. It’s probably still the biggest change we made towards reducing our waste and it changes our lives. No, I mean, really !

Why do I like it so much ?

I use the compost and liquid fertilizer from the worm-composter to grow veggies on my terrace.
  • We reduce the amount of waste so we take out the trash less often, even the cardboard and paper trash.


  • Our trash smells less because it now mainly contains plastic packaging


  • I get not just one, but two fertilizers for my plants and that’s FOR FREE.


  • We do a bit of good to our planet.

What’s composting ?

Well compost, you probably heard of. Organic waste always decays on its own and progressively turns to fertilizer (compost) and then soil. That’s what happens in nature, that’s how soil renews itself. Many gardeners just pack garden waste somewhere in a corner of the garden, leave it there until the leaves and grass turn into compost i.e. solid fertilizer and later plain soil. No work needed, it’s free and it works. Always better than burning the garden waste or put them in the bin, right ?

I knew it was also possible to compost food waste but I always thought it was possible only if you had a garden : I was wrong.

So how does home composting works ?

Like I said, organic material will decay on its own. But at home, if you were to put your food scraps in a container it will start rotting and stinking. Why the difference with nature ? One of the main ones is that many little creatures actually feed on what lays on the ground : rodents, insects, worms, micro-organisms living in the ground, all of them accelerate the decaying process, making it fast, efficient and absolutely stink-free.

And that’s where the little worms from my worm composter are the key because they will accelerate the decaying process ! Here’s a nice little drawing to explain how it works :

The moist atmosphere in the composter allows the worms to climb along the side of the tray and go through the holes in the upper tray where the food is. Like in nature, they climb to the surface, take a bite and go back down. Simple.

Our homemade worm-composter

When the upper tray is full, you just empty the lower one, put it back on top and you’re ready to go !

What you collect in the lower tray is compost and the liquid you get is liquid fertilizer. And it’s all free ! How cool is that ?

The worms travel from one tray to another through the little holes at the bottom of each tray

Now with the main problematics !

What can I put in my worm composter ?

The key to success is to always keep the balance between “greens” (vegetables and fruits scraps) and browns (cardboard and paper). Greens will bring a lot of water so you absolutely want to bring dry stuff to compensate. It’s REALLY important to do so, otherwise you expose yourself to many issues : rotting and stinking, drowning worms etc. See the common issues part for more info on what can go wrong.

Greens : Fruit and vegetable scraps. Raw or cooked. From banana peels to cooked carrots your son left in his plate

Browns : Paper and cardboard as soon as they don’t have any plastic coating. Those are easy to recognize : If you put them under water and that water gently slides on it, they probably have a plastic coating.

Inks used to print on paper and cardboard are normally safe, especially if the packaging is in direct contact with food but it’s your choice. I use my compost in my veggie garden so I try to avoid inks and my browns are mostly egg boxes and toilet paper rolls. Your choice. If you’re still using kitchen paper at home, that counts as brown too. Coffee filters and tea bags count partly as browns too and coffee is particularly good to put in your composter, it will help maintain the perfect pH in the composter.

Egg shell : It’s not a must have but grounded egg shells will help worms digest.

Anything you put in the composter will be eaten quicker if you cut it in little pieces before. It’s not mandatory but it’s better.

Content of the upper tray. You can see apple and banana peels, cardboard pieces and starch packaging chips.

What’s to be avoided ?

You’d want to avoid stinky things like onions and garlic though. They will decay in the end but your apartment will smell like onion soup for weeks. Trust me, I tried.

Citrus peels are not recommended because they bring to much acidity for the worms to be comfortable with.

Seeds and stones can germinate in the composter so try to avoid them. A few seeds once in a while is ok though. I am personally not sorting out the apple seeds when I peeled apples to make a pie !

Fish and meat are not recommended. Worms have no teeth and they will start eating the meat only when it’s so rotten that it’s soft and tender. And you really don’t want rotten meat somewhere in your house, even if it’s to feed your new little slimy pets.

Bread scraps and cereals like rice or pasta can be composted but be aware that they tend to go mouldy. It’s not dangerous but it’s not the nicest either. I personally do it but I would wait until you’re an experienced worm-keeper to try it

Anything hard like avocado skin for example is too hard for the worms to bite in and you will find it in your ready to use compost exactly as it was when you put it in the composter.

Does it stink ?

Not if you keep the balance between greens and browns. You know that nice humus smell in a forest ? That’s how compost should smell. If your compost starts stinking, something is wrong. Most of the time you put to much food waste and not enough paper or cardboard. The upper tray contains then too much water, there’s no room for air in between the pieces of waste. The non-stinking micro-organisms that need oxygen to work can’t breathe whereas the stinky ones that don’t need air thrive : It rots, it stinks.

Where can I put my worm composter ?

A cool dark place is the best. Worms will die if it’s too hot or if they freezes and won’t eat if it’s too cold or to light. That being said, you can put the composter anywhere. I had it in the kitchen before and it was great. It worked like a second bin. My kitchen today is very small so it’s now in the toilets : Temperature is constant throughout the year and most of the time the light is of. Perfect. A friend of mine had it in her garage. Basement, kitchen, hallway, your choice. Just remember that you will have to bring your waste there so it’s better if it’s not to far from the kitchen otherwise you’ll keep the waste in the apartment for a few days and we’re quickly back to rotting, stinking, flies etc. I wouldn’t recommend the balcony if it has direct sun or if it can freeze in winter. Otherwise, balcony is great !

What do I do when the composter is full ?

It almost never gets full ! When decaying, waste loses its volume so you’ll end up with a lot less of compost than the volume of waste you put in. When the upper tray is full, you simply empty the lower one and put it back on top. It is that easy !

What if there are still some worms in the tray that I want to empty ?

Before emptying the lower tray, you can put it on top and keep the lid open for a few hours. Worms hate light and they will crawl back through the holes to the tray underneath. And even if a few worms are still in the compost when you empty it, it’s not a problem, worms are very good for the soil and you won’t deprive your composter because the worm population regulates itself.

What do I do with my compost and worm tea ?

The compost can be used as a solid fertilizer in pots or in the garden. You just have to mix one part of compost with four to five part of normal soil. You can also spread some compost on the ground and gently scrape it to mix it with the ground about 3 cm deep.

The liquid fertilizer can be used like any other fertilizer. But it’s so concentrated and powerful that you’ll have to dilute it (one part of fertilizer with nine parts of water). Be careful, if you use it pure you’ll burn your plants. But if you use it properly, you’ll have the most wonderful plants. Look at my orchids !

What if I don’t have any garden/pots/plants ?

You can just give it to someone ! Your granny, a neighbour, the gardener at work, there’s certainly someone around you who’d be happy to get some free fertilizer. If not, you can just spread it somewhere in a nearby public park.

How often will I need to empty the tray ?

It depends on how big your family is and how much vegetables and fruits you eat/cook. It also depends on what kind of composter you have and how big the trays are. But honestly, not very often. I started my new composter 7 months ago and I haven’t emptied it yet. We’re two people and we eat quite a lot of veggies but we eat home cooked meals mostly in the evening.

How many trays do I need ?

Again, it depends on how big your family is and how much vegetables and fruits you eat/cook. For a family of four, three trays + one for the worm tea is usually enough.

Common issues

The amount of waste doesn’t decrease

If you just started, don’t worry. It takes about 3 months for your composter to “work” at normal speed.

Otherwise, your composter is probably too dry. Maybe you put more cardboard than greens or mostly greens that don’t have a lot of water in them like leek leaves. Have a look inside your trays. They must look moist inside. You should see droplets running down the insides. If not, just stop adding cardboard/paper for a while and try to gently mix the newly added green with what’s already in the composter. Be careful not to hurt the worms while mixing !

If you really are in a hurry to see your waste decreasing, you can spray the inside of the tray with a bit of water.

You don’t get any worm tea

If nothing comes out of the tap, start by checking if the tray contains any liquid. If it does, then it means your tap is blocked.

If you just started your wormcompost then keep waiting. It might take a few months to g

et that liquid gold.

Maybe your composter is a bit too dry. See above “The amount of waste doesn’t decrease”.

It is also possible that your holes are somehow blocked, maybe by wet paper or maybe they are a

bit too small. You’re going to have to go through the holes again with a little stick like a Chinese

stick or a skewer depending on the size of the holes and what you have at home. If it happens often, the holes are probably too small.

Warning : This is not Cola ! I get approximately 1,5L of liquid fertilizer every 3 month


I have to many / too few worms ?

Except at the beginning or after a big problem, you’ll always have enough worms. The worm population regulates itself. It means they will reproduce if they are too few and have a lot of food and they’ll stop reproducing if they are two many. You just need to give them a little time at the beginning and increase the amount of waste progressively.

If you’re under the impression that you suddenly have too few worms, try digging a bit to see if there not just hidden. If not, then you might have a problem. Have a look at the worm tea tray to see if you have a lot of drowned worms there. Maybe the holes are too big or maybe they tried to escape and fell in there. Check if the composter isn’t too wet, too acid or maybe too moldy. Is the room too warm ? Too cold ? Are there to many vibrations in the room ?


It’s probably fruit flies. It doesn’t mean that you did something wrong or that your composter doesn’t “work” properly. It really is a pain in the neck to have these flies flying around though. The reason for them being there is probably that you added a lot of fruit wastes. Fruit flies lay on fruits but most of the time you don’t even know it. When the fruit is overripe and soft, it becomes acid, which allows the eggs to hatch and BAM you have fruit flies everywhere. The best way to get rid of them is to trap them in the composter. If you have an outdoor space, you can keep the container open for like an hour until the flies are gone and then to put a layer of paper or cardboard on top. If you’re a filter coffee drinker you can also spread coffee on top to balance the pH, that works great ! Then keep the composter closed for a week or two. If you don’t have an outdoor space, just put some paper and/or coffee and keep the composter closed. Fruit fly don’t live very long and if they can’t get out to lay somewhere, they’ll quickly disappear.

Worms escaping

You’re never safe from an adventurous worm escaping the composter to go see the world but it happens pretty rarely. But sometimes they escape all at once and as you can imagine, that can be pretty gross. Unless you just left the composter open in a dark room, worms massively escaping ALWAYS mean that something is very wrong in the composter and that they’re willing to take their chances somewhere else to save their lives.

Maybe they are dying because of cold or heat. Maybe you put citrus peels in the composter and it has become to acidic for the worms to live in. Maybe the water doesn’t drain properly and worms are drowning inside the composter. That can sometimes happen if the tap gets blocked by compost particles or sometimes drowned dead worms. The composter is then filled with humidity and starts filling up with water. And you don’t notice it because when you open the tap, nothing comes out.

In any case, check every tray to see what’s going on and where the problem comes from. If you don’t find any issue, the radical solution would be to empty the whole composter, keep a handful of worms and start over. I know it’s hard but it is sometimes better than waiting for all the worms to be dead and for the composter to stink like hell.


Like I said before, it shouldn’t stink. You probably put to much food waste and not enough paper or cardboard. The upper tray contains then too much water, there’s no room for air in between the pieces of waste. The non-stinking micro-organisms that need oxygen to work can’t breathe whereas the stinky ones that don’t need air thrive : It rots, it stinks, soon you’ll probably have flies. The solution is simply to add paper or cardboard and gently mix it with what’s already in the composter. Be careful not to hurt the worms while mixing.

Another possibility is that you just started your composter and you added to much waste at the same time. You need to start slowly to leave the worms time to multiply and populate the whole composter.

Insects and other weird animals

After a few weeks you’ll probably notice that worms aren’t the only ones living in you composter. It’s actually not an issue at all as long as they stay in the composter. They feed on your waste as well and they will help the worms producing compost even more rapidly !


Especially in the beginning, it can happen that your waste in the upper tray gets covered of white or greenish mold. It’s completely normal and it’s not an issue as long as it stays only a few days. When I see it, I always spread cardboard chips or paper on top so that the humidity if not sufficient enough for the mold to stay or that it at least prevents the spores to spread in the room when I open the lid.

Some waste like bread, rice and pasta tend to trigger attract mold as well.

If you notice that the mold tends to stay there more than a week and even expend, try leaving the composter closed for a while.

Stay tuned to know how to make your own Wormcomposter and start composting !











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