Unfortunately, it always happens that the worms escape from a worm tower. With a self-made worm tower it happens a bit more often when it doesn't fit quite right, but unfortunately it eventually happens with every tower.
When you occasionally find a worm on the ground, that's a shame, but it's part of it. A worm is adventurous and always finds a hole and cannot always suppress its curiosity. There is not always something that can be done about this and is not immediately alarming. It gets annoying when a whole lot of worms choose the harepath. Here you will find a number of causes.
The worms have to get used to it.
Especially in the beginning it can happen that the worms are restless and want to escape. This does not have to happen, but the first 2 weeks have the greatest chance. This generally resolves on its own. What you can do is hang a light above the worm bin. The light ensures that the worms stay in the bin better. After a week or 2 the light can go off again.
The worm tower is too hot.
When it gets very hot, the temperature in the worm bin also increases. The moisture in the worm bin can then evaporate, which creates hot humid air. This can cause the worms to crawl up or down. The hot humid air is very dangerous for worms. Here's what you can do in the heat: Worms in the summer
Worm tower too cold.
When it suddenly gets too cold, the worms can crawl en masse into the drip tray. Worms naturally seek shelter from the cold by crawling deeper into the soil. The worst that can happen is that the worms gather en masse to find warmth. The downside is that the middle worms don't get enough air and can die.
This problem can be prevented by ensuring a good winter temperature. Here you can read what you can do when it gets cold: Worms in winter
Wrong food or PH values
Sometimes when a lot of fruit is fed, there is a chance that it will ferment. This can cause the worms to want to crawl out of the tank en masse. If this happens, always consider what was last fed in the worm bin and this differs from previously fed. Removing the food can usually solve the problems quickly.
When 'wrong' food or too much of a species disturbs the worm bin, this usually affects the PH value. Once a month a tablespoon of lava flour or lava grit can prevent or restore this.
Sometimes it is difficult to figure out why the worms escape. At our nursery we sometimes have days when worms are difficult to stay in the tank. We have a lot of contact with other professional worm breeders and often discuss these kinds of topics. It seems that it could also be due to air pressure. What is striking is that I often receive an email or telephone from several people at the same time about escaping worms. My suspicion is therefore that external influences (for example air pressure) can be decisive for the escape. So it is not always what happens in the bin.
Too wet too dry.
When a worm tower is too dry, there is a good chance that the Eisenia Fetida is the first worm that wants to escape. These worms do not like drought. This is easily solved by adding water. When it is too wet for a long time, it can start to smell very bad, this is due to wrong bacterial growth. Here you can read what you can do with a Wet worm bin
Bugs in the worm bin
Read here which animals can occur in the worm bin in the article Bugs in the worm bin