Fluffing up the material in the top tray annoys the worms a bit and inspires them to burrow down quicker. I come back the next day, or longer, when the top tray is drier. By then, many of the worms will have left the dry top tray for a wetter and darker neighborhood.
When the worms have completed their work, it is your turn. To preserve your herd and remove a nice uniform vermicompost from the system you need to harvest your product. This can be a tedious and boring task.
You could just build a frame and use 1/8" wire mesh hardware cloth, and shake the contents of the tray into a wheelbarrow.or you could, ... Build an inexpensive VermiHarvester.
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