Presumo che tu stia usando i red wigglers. Quando le condizioni sono sfavorevoli, questi vermi hanno la tendenza a fare branco per decidere dove andare. È la loro forma di comunicazione. Forse il tuo contenitore di compost è diventato troppo caldo per i vermi. Se possibile, potresti spostare la compostiera in un luogo più ombreggiato o fare ombra sopra la compostiera. Assicurati di mantenere il compost umido (ma non bagnato) e di fornire lettiere fresche e umide.

Their bedding is getting too warm and they want to find a cooler area to retreat to. You can help them in several ways:

1. add a lot more bedding material like shredded corrugated cardboard. Make sure it is moist but not wet. This will increase the mass and make the bedding temperature more stable. It will also increase airflow inside the bedding by adding structure to it (thanks to the bulkiness of the cardboard and the flutes)
2. if you have a tray system, add one more tray full of moist but not wet bedding material. As heats travels up, the worms will go down and find the coolness in the tray at the bottom
3. slow down or stop the feeding during hot days. Adding more food will increase heat. Also, due to the heat, the food will break down too quick, releasing too much water at once which will prevent a good aération of the bedding. Heat + lack of oxygen will be real bad
4. DO NOT water the bin. Pouring water in will help at first but will worsen the situation afterwards because water is better heat conductor than the bedding. You can spray the surface if it dries out but that’s it.
5. If it is real bad, use some frozen bottle of water and leave a bottle or two on the surface. This will help cool down the system. Don’t add ice directly as it will melt and flood the bedding.