The whole world is talking about the trend of growing vegetables indoors and keeping beneficial little worms that turn any garbage into nutrient-rich topsoil. We have thrown ourselves into the adventure worm box for you.
A person in Germany produces around 60kg of organic and green waste per year. Many households in the cities do not have a separation between household and organic waste, so everything is disposed of in the black residual waste bin. Each inhabitant produces an average of 475 kg of residual waste per capita per year. These numbers alone sound the alarm and show that each individual can bring about change. A small separate “compost” in the living room, well presented as a stool, can decompose up to a kilogram of organic waste a day (1000-1300g worms). Normally you start with a colony consisting of around 500 worms. These can process a handful of organic waste a day, which is between 100-200g.
How do I build a worm box?
On the Internet you can find various offers of worm boxes, they are already ready-made, as a self-assembly kit and as instructions for the hardware store. In principle, they all have a similar structure. You need boards for a wooden box or just a wooden box, ideally made of untreated wood. Air holes must be drilled into these. Then you use plastic boxes with a hole in the bottom or a wooden board with small holes as an intermediate floor. This is attached around 10-15cm above the ground and can be removed. A collection container is positioned below the intermediate plate, and the worms are placed above, mixed with soil and soaked cardboard. To protect the residents from drying out, they are covered with a hemp mat. For the first two days, the worms are only sprayed with water. After that, the small subtenants can start processing the organic waste. Harvesting the soil requires a hard plastic box with holes in the bottom that fits completely inside the wooden box.
Schematic structure of a worm box.
Can the little helpers eat everything?
No, worms cannot eat onions, garlic, meat or dairy products. I would also stay away from coffee and tea bags. The little ones can shred wood, cardboard, paper, egg shells and even hair.
Where can I get the worms from?
Compost worms belong in the worm box - Eisenia andrei, Eisenia foetida and Eisenia hortensis - are the most well-known species. You can get them online, for example. They are then supplied in a bucket with air holes and soil. This should rest for the first day. If the worms are immediately transferred to the new home, it can overwhelm them.
How can I harvest the earth?
After about 3 weeks, the first time can be harvested. Depending on the size of the worm box, it may take longer. As soon as the worms have produced so much soil that the harvest box no longer fits in without being able to completely close the wooden box, you have to harvest. Now you put the box on the worm-soil mixture and throw the coming “food” into the box. After 1-2 weeks all the worms are in the box and you can remove the soil. In between, some worm strains produce worm juice - this can be used as fertilizer in a 1:10 mixture with water. The juice collects in the tray underneath at the bottom of the box.
Where is the best place to put the box?
The worms prefer to be in the kitchen. Conveniently, you can disguise it as a stool and put it anywhere. They do not like drafts and large temperature differences at all. Between 15-25 degrees is the optimal temperature. In summer you can also put the colony on the balcony or outside the house. Sub-zero temperatures let the worms freeze to death.
How much will this project cost me?
A box with a full population as an assembly box is available from 199 euros. Ready-made stools are similarly expensive. Do-it-yourself stores advertise with material costs for the box between 50-80 euros. For a colony you have to calculate around 30 euros, the right boxes for harvesting and for the juice cost around 20 euros. You should always protect the worms from drying out, for this hemp mats are used (about 10 euros per mat). All in all, a self-made box costs 100-120 euros. Small vegetable crates, a discarded stool and an old tin can already replace some parts. At least 40 euros must be calculated, the rest is collected through upcycling.
How can a company use this box?
We make some wooden bracelets ourselves. In every company there is waste and also rejects due to mistakes. The worms work off this proportion of "unsaleable" and cardboard, as well as paper waste. Our future model envisages that all our bracelets will be sent back to you after their "luxury life". We want to recycle all components. The worm box is a first step towards that.