Esmé,
If I understand you correctly, your bin was half full of scraps before adding the worms ?
It sounds like your bin is indeed composting by the sounds of it and having the worms in a hot bin like that is not ideal for your new residents.
The heat from the composting process is driving off you moisture at least on the top.
I would suggest to recue the worms from the bin while still possible then remove most of the hot composting materials and read the below post from our worm GURU Kelly.

TC

Posted by: Kelly_Slocum sw WA state (My Page) on Thu, Jun 2, 05 at 9:23
Many of the suggestions you read on how much a worm can eat and how much the bin can/should be fed are misinterpretations of recommendations that come from Mary Appelhof's book "Worms Eat My Garbage". Many of these recommendations were not based on scientific research, but were generalizations Mary had to make to aid a public demanding answers that science had not yet found or about which could not make general statements. As such, she intended them as guidelines to aid people in beginning a bin, as she recognized better than almost anyone that how much a worm can eat depends on the character of the feedstock, the environment, etc, etc. The internet turned Mary's generalized guidelines into "facts" and "rules" for worm behavior and worm bin management, however, and have now become so overstated as to be incorrect. When beginning a new bin, following the guideline that the system will process a weight of feedstock roughly equal to the weight of worms for the first week or two is a reasonable expectation. As the system matures, however, it will be able to process more and more, dependant, of course on the character of the feedstock and the environment. The wise vermicomposter will feed their bin not based on the suggested feeding rates found in a book, but on their own observations of how quickly their system is managing new feedstock additions. Each time the worms move into a new addition of feedstock this should be an indication that more feedstock can be added. The first feedstock does not have to be fully processed, it simply has to have worms actively working in it, indicating that it is sufficiently biologically active to be available to them. Adding new feedstock at this point gives the new stuff sufficient time to become biologically active while the previous addition of feedstock is being processed. The average healthy home worm bin supports about 1.5 pounds of worms per square foot of bin surface area on the average. The most populous vermicomposting system every documented supported roughly 4 pounds of worms per square foot of bin surface area, but that population density could not be sustained indefinitely. Don't get too caught up in the question of "how many worms are possible in the bin?" or "how many worms should my bin hold?" as the worms will populate based on the amount of available food and space. Put some worms in the bin (hell, you could begin with just two, or, believe it or not, even ONE, and end up with a maxed out population in several months), keep it moist, add some feedstock and they will make more worms for you at just the right speed and to just the right population level for the system as you are managing it. As to recommendations to add "decomposing material", that is exactly what you are adding when you put feedstock in the bin. Some folks suggest "pre-composting" the feedstock before adding it to the system, but I have to wonder what they perceive is the advantage to pre-composting it in a bucket separate from the bin over simply allowing it "pre-compost" IN the bin where there is massive biology to aid in the process. Sometimes the suggestion to add "decomposing material" refers to the use of compost or worm castings as a part of the bedding in a new bin to ensure the system has a relatively high level of biology at the outset, and this is actually good advice, though is certainly not a requirement. Compost in the bedding often helps the worms settle into the new environment more quickly than they would in a bin full of shredded paper and kitchen scraps alone. I know, I know, this is another of my long-winded posts, but the answers require some explanation if what we want is a truly educated vermicomposting public! I am working on brevity (you should have seen this post before I edited it!), so please be patient with me; brevity is not a general part of my nature and at 43 changing takes some time! Let me know if you have more question, Robin, or if any of this needs further explanation! Kelly S· Posted by: Kelly_Slocum sw WA state (My Page) on Thu, Jun 2, 05 at 12:59How to determine when the bin is ready to "harvest" depends on whether you are pocket feeding or top feeding. If you are pocket feeding then it's time to harvest when essentially all of the bedding has been converted to castings and is no longer recognizable, and the bin volume has decreased by roughly half. Top-fed bins are harvested when the bin is filled all the way to the top. Time to harvest is usually shorter in pocket-fed bins than in top-fed systems, and (surprise!) is widely variable, dependant on bin size, how much the system is fed, environmental conditions, feedstock, blah, blah, blah, blah. You've got a better grasp of this than you credit yourself with, Robin, if your questions are any indication. You are asking the right ones, have clearly not bought in to everything you read on the internet, and are thinking critically. Fascination and common sense are the only real prerequisites for effective vermicomposting on the part of the human involved, and you appear to have these in fine measure! Kelly S

hi, it sounds like there's a couple of things going on, the bin is drying out, and youve got too much food in there. the drying could be from the food composting, but also if the weather is hot at the moment.

I use coir for bedding because of my hot dry climate, it works so well and is low maintenance because it really holds onto the moisture and stays cool. I found things like shredded newspaper just werent suitable on their own in my climate because it dried out so quickly in the heat.

I think your worms are very unhappy right now, so my advice would be to get a coir brick (I get them from the hardware store for $2), empty out your bin and put the swelled up coir in there, fish out the worms and put them on top. then get about 2 cups of the food scraps and put that in for food and let them settle in. dont feed them again until they start eating, which can take a little while to begin with as they get used to the new surroundings. Its not the only way to go about it but if you do that, your worms will love you for it :)

Thanks TC and Trance for your help!!!

I had been piling scraps and paper to the bin, to get it ready for the worm. It took two weeks to get the worms, so the bin got filled up. Wrong strategy I guess. ::

You're right, most of the worms on the top bin doesn't seem happy because when I checked the catch bin today, half of the worms have already migrated down there. Fortunately, I placed some leftover moist shredded paper there meant to catch leachate. Well, there's no leachate and the paper are still moist, so I guess they prefer this environment better than the top bin. That took care of separating the worms, I think. Then, I added more bedding and about 2 cups of the semi-composted OM.

As for the top bin, there are still a lot of babies and fat worms left there. They seem happy and feasting. The OM has shrunk too, so maybe they did eat last night. I covered the top bin with more moist bedding and cardboard.

I ended up with two working bins. Both have vent holes. If the tenants on the upper bin is unsatisfied, they can more to the lower apartment. I plan to combine them again, maybe later this week ... and follow the feeding pattern described by Kelly.

Now, I just gotta find some coir.

Thanks again. I was panicking yesterday, but I think I understand the worms better now.

"so I guess they prefer this environment better than the top bin "

they do like things to be nice and cool and moist so you are right about the bottom bin, it sounds like its moister and cooler down there. once you try the coir youll never look back in a hot climate, it makes it so much easier and it keeps the moisture levels pretty consistant, and needs wetting down much less often. if you cant find it locally then try a google search on 'coco peat brick' (another name for the coir bricks) and youll find some online stores that sell it. I tried to put a link in here but for some reason it keeps getting rejected, but if you do a search then youll know what the coir bricks are all about and what to look for in the shop. once you get the moisture problem solved the rest is easy and just comes down to watching the amount of food theyre eating and keeping just ahead of it so that you dont overfeed the bin.

Hi Trance! I found coir mats at home depot but I think they're for hanging baskets. I'll check out HD later.

So far, so good. No worms tried to escape yesterday and last night. The OM continue to shrink, faster (I think) at the lower bin. Both bins seems to stay cooler, too.

I meant I found the mats at walmart ... and will check HD ... sorry

hi DH, I sent you an email :)