Moving worms to a new tray
I bought a bin with three trays. After more than a year, I have finally managed to fill the first container. I have made a bed of cardboard etc in the second container and placed that on top of the first. A lot of worms have migrated up to the second bin and now:?
1) How long do I wait before harvesting my compost from the first bin?
2) Why do I need a third bin? I would have thought that I would take out the bottom bin when all the worms have moved up and then, just carry on as before. Why the third container?