Making a home composter with worms

I will share here a low cost solution for the recycling of organic waste, appropriate for apartments and urban housing that do not have a piece of land or an outdoor area. This construction is inspired by the Cadico earthworms nice project. The photos are from the composter I made here at home  : )  It’s called a Vermi composter because we use worms in the process, uhuuuuu big thanks to the worms, they deserve!

To make this kind of composter, it is important to use stackable supports to separate the different stages of composting.

In this case, I used 3 buckets of margarine 15L reused. You can ask for them for free at local businesses such as coffee shops, bakeries, juice houses, etc.. They are stackable and perfect for the job!


The first step is to cut the center of the lids that stands between the buckets. Leave a border so that a bucket can stay on top of the other (this red lid is perfect for this because it comes with a delineated border):





Then we will make holes into the bottom of the 2 buckets that will stay on top and receive the organic waste. These holes are to drain the leachate to be stored in the first bucket underneath (this one has no holes).
You can use 4 mm drills (suficient for the worms to pass through).



Then, we use thinner drills, size 1, or 1.5 mm for making holes in the top of these 2 buckets to allow the entry of air, very important component of a good composting. (If these holes are too big, the worms will pass and it will atract some other insects in your kitchen).



We also make small holes in the lid that will stay on top and was not cut:


Now the suggestion is to make a very beautiful painting in the buckets to forget all that margarine past and decorate your kitchen!  : D

I made some stencils with masking tape, very easy to do :








Now that we have our buckets beaultiful and prepared, we can start composting! uhuuuu

We’ll start with only 2 buckets, the third one will be awaiting.
So, let’s prepare the one on top to receive our organic waste.

Place a first layer of compound or forest land. This land is rich in bacteria that will help in the decomposition process:


Now we can put our organic waste and always cover it with dry matter:


Over time, the compound begins to seem a dark mass:

When the bucket is already filled with this dark, pre composted mass, we put our dear worms! (if they enter at the beginning they might die with the heat generated)


We use the California red worms. You can ask some for someone who already has a worm farm and soon they will reproduce and increase in number. You can also buy them from a producer or even through the internet.

Earthworms accelerate much the decomposition process because they can eat daily the equivalent of its own weight (!) Besides enriching the compound with their droppings, called humus.

When the upper bucket is full…


it will be time to enter the third bucket on top of the stack! So, first, we put the other lid with a hole in the middle:


And then we put the third bucket, leaving the system as follows:


Now, the top bucket will receive the organic waste generated by the house. Meanwhile the central bucket, full of waste, will be resting while the worms do their work.

After eating and making compost, the worms will look for new food and then go up to the top bucket, we hope so. (or you can give then a hand!)

When the top bucket is full of waste, the compost in the central bucket must be probably ready, or almost, and can wait in other recipient. Then the top bucket goes to the middle and the middle bucket will be free to start a new cycle on top!

Meanwhile, the first bucket underneath will be storing all the leachate from the system:


This dark liquid is full of nutrients good to get back in the soil, but also very strong… So we can dilute it in 10 parts of water to have a nice biofertilizer! : )

And there you go!

#Some important things:

. The process of composting requires air and humidity (around 50% humidity)

. Try chopping food residues to facilitate decomposition.

. There is an Carbon x Nitrogen ratio to be maintained (initially 30:1). In practice, always cover the food waste with a good amount of dry matter such as straw, sawdust or leaves.

. The composting process generates heat, reaching between 60 and 80 degrees Celsius (!). Which is good because it helps kill the pathogens. When the temperature drops, this indicates that the compound is stabilized.

. What CAN go :::
– Fruits, vegetables, grains and seeds;
– Tea bags and coffee grounds (with filter).
– Leftover cooked or spoiled food (no exaggeration) and eggshells.
– Straw, dried leaves, wood shavings, sticks, garden pruning.
– Paper towels, paper napkins, bread paper, cardboard, newspaper.

. What MUST NOT enter :::
– Meat of any kind;
– Dairy products, oils, fats;
– Feces of domestic animals and used toilet paper.
– Excess of citric fruits (orange, lemon, pineapple, etc.);
– Excessive salt (leftovers), garlic and onion.

. Cadico earthworms

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Acerca de surian

Surian researches open source and social technologies in Brasil. He graduated in media at UFRJ and went to live in the countryside where he learned to plant and worked with a seed bank, agroecology and communities. He is currently studying permaculture, mesh networks and non-violent communication as ways to make people closer to each other. In the meantime, he enjoys making music, poems, inventions and putting radios in the air.