I went to a fabric store and got a few yards of nylon fabric - black, a close weave. Water gets through it but not worms, even babies, and being nylon it won't rot.

A piece of that sits between each worm factory base and the lowest tray. The fabric collects a funky layer of compost plus a few worms who like it down there, but it keeps worms out of the spigot. Every 2 months or so I still take the whole system apart, hose down the bases and fabric, move the bottom tray contents to my holding bin and so forth, but this keeps things under control the rest of the time.

I use pieces of the same fabric to cover the tops of the bins during the summer, to keep winged insect activity from getting out of control.

You are my new favorite person, Colin3! I love looking at my worms, spying, thinking. But dismantling the thing is no fun. This sounds like the perfect solution. Do the few worms who get through it actually continue to live? Bizarre! I guess they're eating their own poop. Is there any smell from dying worms?

Covering the tops is another stroke of genius. I have an empty tray in between trays to (maybe) keep my fishing worms from my EFs. Temporarily! I know it won't last long. I'm hoping to put the nightcrawlers outside somewhere once I get the new house livable, but can't get to it yet. It does make the top of the bottom bin dry out quite quickly. Do you think that's a problem? Then again, the higher up bin with the Euro nightcrawlers is quite dry on top too, even with the WF lid. I can't decide whether I should wet those up by spraying or not.

So this would solve the flying insect thing too. WOW. Even every couple weeks would be better than dismantling daily. The daily rescue mission was not in my plans.

Oh, wait: funky? Does it stink badly?

Thanks, Colin. How long have you been doing this? What is your system?

I have a couple of Worm Factories, going on 2 1/2 years, plus temporary finishing or overflow bins depending on flow.

So far, worms have not gotten beneath the bottom fabric barrier, but some do hang out on top of it -- that is, below the mesh bottom of the lowest tray, wallowing in the black sludge that collects atop the fabric. (I put the fabric on top of that squarish plastic "worm ladder," so water will still drain out of it, kind of.) Funkiness: the black sludge has a marshy smell, but it's not detectable from a distance. Then again, I keep all this an outdoor closet, not in the house.

I don't see any reason why other layers could not be separated from each other by fabric.

I should emphasize that the fabric up top does not stop flying things -- those little flies can crawl too. But it means I don't get clouds of them. Just lots of cute larvae.