Having previously built the base of the wooden worm bin, as can now be seen in the pictures (click to enlarge), I have constructed the top section. I purchased a roll of 2′ wide 1/4″ hardware cloth for less than $6, cut to length with tin snips, and stapled firmly to the bottom of the new top. Referring to the pics, I also attached little legs to further reinforce the square and provide stabilization for the top section, and also added a block into each internal corner. The part that I have left out is the construction of a simple wooden top (used to cover both the bottom section and later on the top section). However, I will leave this part to you, and I just use a section of exterior plywood.
Now, my vermicompost is not quite ready for me to add this top section, as the base section is only about 75% full. As previously mentioned, when it gets full, I will then quit adding food for about 1 week to ensure that the worms are ready to “move on to higher ground” (pun intended). Then I will attach this top section and start adding food. The worms will then leave the base and crawl in mass into the top section. There is a little ‘sag’ in the hardware cloth such that the weight of food added to the top will allow the worms below to traverse this region etc. Of course, during this time I can start taking vermipost out of the bottom section as desired, but I can also just leave it for awhile to make sure that all the cocoons have hatched and new juveniles have had a chance to move to the top. To enhance cocoon production after worms are fully established, beds should be allowed to dry until the top 2 inches are barely moist. Then sprinkle sufficiently to restore normal moisture content.
My plans are to then remove the bottom section of vermicompost, and then dump the top section back into the bottom (thus starting the cycle all over again). Of course, more sections could be added to this stack as needed, and thus one can incorporate any logical system that they wish according to their imagination and goals. So far my worms are loving their new wooden home and multiplying rapidly. I would be glad to hear any comments from any “worm experts” out there (as I don’t claim to be one)!
If you do not wish to build your own, you might consider one of these..Gusanito Worm Factory Farm Bin 5 Tray Stackable