Worms retreating to the bottom? You mentioned using cardboard, awful lot of starch in cardboard, plus you would be blocking free air flow, and hindering water drainage/ evaporation, maybe too much so. Personally I never used cardboard, just some light layers of newspaper, and yes, they will punch, lots of holes through it. Processed paper has many different types of additives, also. Nothing with scents added, newsprint works, but, sparingly. I use newsprint, shredded, to fill spaces, like the bottom water collection tray, this helps the worms, to crawl back up into the bin, also between bins, as they become filled, again this aids the worms in their movement, and they do move, quite a bit, it seems. Soy based inks are OK, but, old style ink, had a high chemical base, and might make for bad growing conditions. I have, two of the stack bin arrangements, four bins each, but, never more than that. When they have moved up to the second or third bin, I remove the bottom bin, and empty it, shifting the product, as I go. You might loose some worm's, but, never too many. WHY do I sift, to remove any undigested items/ large itmes, that might be leftover. This will tell you, what the worm's really like, and what they don't like, to eat. Egg shells are often left over. I use our spare bathtub, as a place to keep mine, it works out, just fine. Easy to clean up afterwards, and contain any liquid spills, if, needed. There is very little smell, and most of my guests, don't object, if, they even know. I keep the curtain closed, and open it when there is no one around. I guess it largely depends on what your feeding them? I have never had such a problem, as that. Some things to suggest, keep them in a dark and somewhat cool location, no direct sunlight, and avoid constant opening of the top cover. I have a dark light(what?), a bulb that is blue in hue, for the feeding times, this doesn't bother them, as much as a regular incandescent bulb or ambient lighting. No citrus, acidic items, bread like items (yeast), tend to become too hot. I don't use any, or, very little meat items, vegetables (even grasses, although, they consume this slower, grass can also have uneeded chemicals, depending on your lawn aditives))are there preferred feed items. Occasional water added is good, but, spritzed on, not dumped, too much water, is as bad as too little. How many layers are use currently using?? Don't overload feed, above what they are able to consume. Reduce the number of bins, and see if this doesn't help. Is the bottom bin, or, the water collecting bin, too wet, too dry?
You could try using a soil thermometer, to track batch heat.
And room temperature should be no more than 70-75 degrees, and the bins should have ample air, for intake.

I am willing to help further, if, needed, feel free to contact me.

PS, one other thing, were did you purchase your red worm's, there are different types, believe it or not, some hardier, and some less so. OH, yes, do you know about how many worms you ordered, as in pounds of worms, about 1,000 worms (all stages of growth)per pd., is the rule. It takes at least 2-3,000 worms, to start, for any kind of real production, to occur.

I use lots of shredded corrugated cardboard for my worm bins, they love the stuff. I'm not using any sort of stacking system but I have used a layer of screen in the bin and started feeding on top of it to try and get the worms to move up to make harvest easier. I found that if you feed a lot of nice juicy stuff up high the tasty juice drips down and the worms can continue feeding in the lower layers on the microbes that grow in that nice tasty juicy drippings.

My first bin full of worm castings didn't get harvested till somewhere between the 4-5 month mark after starting the bin. I started with two pounds of a mixture of at least two types of composting worms. My temps are probably a little too warm for good worm breeding during the summer but most of the rest of the year is pretty good for them. My bin is 2' by 4' but I only used half of it when I first started. The worms are now filling not only the first 2' by 4' bin but a second 2' by 4' bin as well and it is only about 4 months after that initial harvest. The worm herd is not a year old for me yet.

Anyway, as to how long it takes to get black earth like material. I don't know as my worm castings are more like wonderful rich brown earth with a slightly sticky nature. fun stuff to stick the hands into. I got a good amount of castings out of my initial two pounds of worms after about 5 months and I could harvest another load now but I'm trying to figure out how to convince more of the worms up out of that layer before harvesting.

Here is a link that might be useful: My first worm bin

tclnx, I read your site where you said that you tried a divider in your bin to get worms to migrate to other side for new food source. I was going to try that method until I read that you said it was slow going. My thinking was that I could pile up the castings on one side and let the worms migrate over to new food source while letting the remaining large pieces in the castings to break down even more. I thought that a month or so would allow time for some of the cocoons to hatch on the old side and maybe the babies wold migrate over too. It seems that this method would be better than the top screen since there would be no juices dripping down. So I guess my primary question is does migration take place at all from one side to the other or as you say just very slowly. Also what time period does very slowly cover. Thanks

I think to get all the worms to move over from side to side would take months like several months or six months but I really don't know since I haven't really tried being that patient. I wound up picking many many worms and cocoons out and I probably left it two months.

The screen idea seems kinda good in that it makes lifting the worms out into another bin easy but I can't say that they are leaving the older castings very fast at this point.

Here is a link that might be useful: My Bin

It then appears that redhen has the right idea using light to drive worms in the post below. You have to be very vigilant using this method in order to try and save some eggs.

Re:Harvesting Worms - 2007/10/23 17:34
For my tote type bins, I set up another bin with some vermicompost food and damp paper bedding, (including any recognizable food and paper from the bin to be harvested).
I have a screen basket, that I made out of hardware cloth. It rests in on top of the new bin's bedding.
I then scoop out compost from the older bin, about an inch deep, in full sunlight, onto the screen basket.
The worms will move down, through the screen away from the light, into the new bin. Dump that compost to a storage container and scoop another bunch of VC and dump until it is all out. Takes me about 45 minutes to harvest a 10 gallon bin.
If you want, you can check the VC for cocoons and add to the new bin.
Susan Quinby-Honer
redhen@nc.rr.com