How the stacked trays systems (I'm rocking a Worm Factory 360) are supposed to work: is you only put food into the top tray. When it is full enough (1/2 to 3/4), you put another tray on top. Some of the worms will continue working that tray and some will migrate upwards to the new feeding tray. You should stir the trays to aerate every so often. I take the lid off and set it upside down. I then stack all the trays on it in reverse order. When I get to the bottom tray, I stir it. If it looks like it's ready (finished vermicompost, no recognizable food or bedding) I set it aside and the tray that was on top of it becomes the bottom tray. I stir it, then add the next one and repeat. When this is done, they have all been stirred and are in their original order, except for the bottom one. I now put it on top and stir it. The worms don't like the light and will migrate down to the feeding tray in time. You can hasten this by shining a light on it (I have a small gooseneck LED task light that I set up) and stir a few times per day for a day or two. Then remove the finished tray and put the lid back on. You can take the tray of vermicompost straight out to the garden, or you can put it into a plastic bin for storage. Be mindful of not letting it dry out too much, and be sure that your light stays on around the clock.
I'm harvesting a tray right now...this is what the finished product looks like. The second photo is after stirring. There are still quite a lot of worms and I make sure that the center is not too thick, or it will be dark enough for them to be comfortable where they are. It is not critical to get every worm and cocoon out, those are good for the garden too (although the adults won't necessarily survive in winter)
Oh, and coconut coir is not needed. I use mostly shredded newspaper...occasionally coir and or pumice.
Hope this helps
