By placing bins on top of the others eventually you just get a very dense and packed material that probably could even go anaerobic. I just posted pictures of my new flow through bin http://forums.gardenweb.com/forums/load/verm/msg0422570210660.html. What you are mentioning here is more of a stacking bin system. A stacking bin system can work but generally the top bin would not press on the contents of the bottom bin, it would just touch it so the worms would migrate upwards. The thing is the worms will decide where they will go and are probably staying put in the lower levels as there is enough food for them.

Flow throughs sound neat. But I don't think that with a new place to make livable, an old house to clear and sell, and a new garden, that I can be playing with my worms as much as I like. I know that you don't like pre-processing, and boy, do I get it. But I've been thinking: since your setup is small, and knowing that you built it from gathered worms, which I imagine took a lot of time to get to a good number, that you probably DO need to pre-process. Or, of COURSE bigger is nice, if it can be done! What I learned when I went crazy several years ago and filled up my whole laundry room with worms (and made my house unlivable) is that anything that makes it go faster is pretty much worth it IF compost is your goal. I hate to use the electricity (and the time washing the machine, whatever it might be, AND the energy to do that too) to process it. But I found sticking baggies that I use and reuse and reuse into the freezer does a really good job of breaking things down. Or any container that you might have. I like baggies because I can mold them to fit whatever space there is. If your bin is too moist, you can even drain the liquid from the baggies on the yard or flowers so as not to waste it. I freeze all mine now, except yard stuff. It's worth the guilt about power for the time savings. Because, well, I'm gettin' up there! I don't have all the years left that I used to! I had lots of patience back when. But now, if I'm growing black gold, dammit, I want it sooner rather than later. :D

The mites will likely not go deep in the bin, nor will much else but the worms. One thing I read was that if you are really upset about non-worm visible lifeforms in the bin you can do one of several things... One (which I prefer) is to put your bins outside where they belong if you don't like living with extra lifeforms and micromanaging a bin that is taking up the most expensive area of your property. Another time proven technique is to ignore your boxed dirtfarm so that less hours of your week are dedicated to worrying about something that is taking care of its self. If plan A and B there don't work... You can take advantage of the fact that worms will dive for cover if you dump extra water in the bin, and all these mites, ants, pillbugs, and whatever else, will surface... Where you will be waiting with a grin and a blowtorch. I've found the blowtorch method to be highly effective at reducing the populations of insects that gravitate to one location. A reduced population of insects will quickly breed back up to swarming strength in the protected shelter of a house though, and since I understand that my ancestors differentiated indoors from outdoors by what one expects to encounter there, I keep my bin in the chicken coop (unheated, Zone 5). Beyond that, the larger your bin, the less things that can possibly go wrong with it. If it's deep, it can't overheat or freeze. If it has high volume, it can hold more worms than can be preyed upon and excess can be taken for whatever you want. If it has much room, the worms can separate into their personal favorite locations and run away or toward hot composting locations. If your bin is large enough, you can't over or underfeed it simply because the worms can express their natural survivability, which they can't do when you keep them in a little test-tube bin indoors.

How a forum works is people post questions and get answers posted publicly from an assortment of other people. In that manner everybody learns a little bit from each post and group knowledge is expanded. Skipping that step makes for a boring board. Hiring a consultant gets an in depth look at a particular system from top to bottom including answering questions one might never even know to ask about improving the health and productivity of said system. The senior vermicompost consultants on this board are not available for hire at any price and would be unlikely to personally e-mail to you their answer. The only way to get the benefit of their knowledge and experience is to share a bit of your knowledge and experience in this or another public forum. That is how most public forums work. The more you can tell us about your system, the more we can help with answers that will meet your specific needs. A bit of research on the topic of vermicomposting available right in the archives of this website will freely give you knowledge of the topic. It does take just a few hours of work. That is what we all did. Then we asked questions of a specific nature that may have not been covered 200 times in the archives. A better question will get you a better answer, often many better answers. It seems to me an Urban Farm Manage would have a lot of information on moisture percentage, food diversity, temperature control, and pest control to add to the often times rambunctious discussions here. Also, like fencing, breastfeeding, and managing people, you may find that vermicomposting is more of an art than a science. Often times a full knowledge of how the system is working involves getting right in there with the process to see exactly what is going on. Most likely one of your experienced workers is vastly familiar with the answers to your questions. They could tell you more about the system than any book. Worms do not read the books thus they do not know how to behave according to it. It really is a hands on learning process to be able to judge the answers to those questions. moisture percentage: of the food, bedding, results? food diversity: what types of food are you considering? bedding: why no question about bedding diversity? temperature control: Are you vermicomposting in a temperature controlled building? pest control: inside the bin or outside the bin such as cockroaches, mice, rats and snakes. Who are the benefactors of your vermicompost? Is it simply a method to handle green wastes or to gain compost? How did you happen to be in charge of a a custom built mechanical flow through system without a familiarity of the process of vermicomposting? What type of worms do you have? How are you sure? Anything I missed I am sure a few of our resident senior vermicompost experts and even up and coming regular level, and a few newbie level posters will correct. The newbies are the posters with all the great, new ideas that keep the board squirming. ~ Ugly, Mean, Old, housewife with a worm or two in the basement