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Outside worm compost
Our outside worm compost

Worms for use in composts
Worms for use in composts
Worm compost

There are different kinds of composts. A regular compost heap is a kind of aerobic compost. It decomposes with the help of heat and micro-organisms. It is good for garden waste but as it is an open compost it might attract flies and rats if you put kitchen waste into it.

A worm compost is ideal for kitchen scraps. It produces a rich compost that can be used as a fertiliser or for container gardening.

Worm compost bin
When you want a worm compost you need a suitable container. We have built a wooden container but we are also using plastic boxes which can be placed on top of each other. They are very suitable for this purpose as you can put many of them on top of each other. The worms will then by themselves climb from one box to the next when they have finished eating in the first box.

Our boxes contain about 25 litres each. You need a capacity of about 100 litres per person to be able to take care of all your kitchen scraps.

The container we have built of wood consists of two compartments. We fill up one of them completely until we start the next one. When the worms have finished processing the scraps in the first compartment they will crawl on to the next one. To make this possible we have made small holes between the compartments. When they have finished the second compartment the compost in the first one is ready to be used and we then take it out and start to fill it with kitchen scraps again. Each compartment holds about 70 litres. There have to be drainage holes in the bottom to make it possible for the water to get out. This water is very nutritious and can be used as a fertiliser.

What kind of worms can be used in the compost? The best is to get a special type of earth worms, Eisenia foetida, which naturally live in manure heaps. You can pick them yourself if you know where to find them but the easiest way to get them is from someone who already has a working worm compost. There are also shops that sell them. You don’t need a lot of worms from the beginning as they will breed quite fast; you can start with a hundred. Make sure you also get a bit of compost with the worms as it contains worm eggs. After two months the amount of worms will have doubled.

A earth worm eats its own body weight, 0,5 gr, every day. It means that you need about 1 kilo of earth worms for every member of the household.

The worms will work in you compost as long as the temperature is above 10 degrees C. They will survive as long as the compost is not frozen. If you have your compost outside in a cold climate like ours (Sweden) the worms will only be active from April till October. This means that you can’t really use it in the wintertime even if the worms will survive. Better then to move the compost indoors in the winter – it will double the amount of fine compost that you can produce in your little soil factory.

The worms don’t like it when it gets too hot. For us that means that the compost is placed in the shadow. If you live in a warm country this might be tricky and the best place for the compost could be in a cool cellar.

Get started
Wherever you place it, it is best to start it in the summer outside and learn how to handle it. Once you have learned how it works you can move it inside. Then you also add the worms and some kind of fibrous material, i.e. leaves, straw, shredded paper or peat.

You start the compost by filling up the container at the bottom with kitchen scrap. Then you also add the worms and some kind of fibrous material. You can’t only use kitchen scrap in the compost as that is too rich in nitrogen. You need to add some kind of organic material that will balance the kitchen leftovers, like peat, leaves or straw. You can also use paper; take some pages from a newspaper and rip it into small pieces. Every time you put a new layer in the compost from the kitchen you must cover it with organic material to get a balanced compost. The compost should always be moist so add water if it’s getting too dry.

In the beginning, when you don’t have so many worms, you can’t add so much waste. But when you get more worms you can add a lot. Once you have filled up a compartment you move to the next.

What to compost
All organic material from the kitchen can be put in the compost. Peels and skins from fruits and veggies, leftovers from the meals, tea-bags etc. Even meat and fish can be composted in small quantities. The worms will process the material faster if the waste is cut into small pieces. We have had some problems with orange peels in the winter as we eat a lot of oranges. It takes time for the worms to process the peels so we don’t add all the peels to the compost.

The worm compost is a living compost and the balance can be broken if you add too much or too little of something. Here is some advice what to do if you get into compost problems:

Ants - If you get ants in you compost it means that it is too dry. Just add water until it is moist.

Bad smell - This is a sign that you have too much nitrogen compared to carbon, i.e. too much waste compared to fibrous material. Add more peat, straw, leaves or whatever material you have. The smell can also be a sign that the composting process has slowed down because it is too dry or too wet. Then you have to water it or add more fibrous material that can take up the extra water.

Flies - Top the kitchen waste with peat and see to it that it covers the scraps completely. If you have the compost inside the house and get flies you might have to put it outside until you have solved the problem.

Text: Ulrika, translation from Swedish: Karin
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