That is what it is we are all trying to figure out. It probably depends upon what you are using for feedstock and bedding. You say 2X2 but is either of those the depth? Also vermicompost does not just nicely fall down to the harvesting system. what can be reached falls down and the rest... STAYS RIGHT WHERE IT IS. Defying Gravity. It is positively Wicked. Not even Flying Monkeys can scare that compost into falling. ~ Elphaba

If you haven't read it already.... the trials of DIY FT construction ;)

http://forums.gardenweb.com/forums/load/verm/msg0903044524247.html?10

The bin I am designing is 2' x 2' x 2' ( which allows 8ish inches at the top of free space ) I am trying to work out a harvesting mechanism that doesnt require me to be on my knees dragging a fork or what have you up between the grate to harvest the VC. Some of the threads I have read say the VC kept falling between the rails....while others state the stuff stays suspended. So I am at a bit of a stalemate with the design until I get more info. Amazing forum this...so much info....so many people. And not one has made me feel stupid (yet) ... lol

Hehe. Well as mentioned in the other thread, it really doesn't want to drop period. That's free hanging in the middle of the system without rails blocking it. Lots of FT systems have harvesting mechanisms because the stuff won't pass through the bars or wire bottom by itself.

So any sort of bottom would stop VC from passing through. Then you need some harvesting methond like one mentioned in the link. I think your problem might be more getting stuff to the rails as the others had.

PS, not sure which treads say stuff does get past the rails, but that certainly could happen on a new bin when you don't have any VC yet, maybe just scraps and cardboard. That's why you need a good flat built up bottom of cardboard to support the stuff until the worms do there thing. Once you have a solid mass of VC though, it holds.

I think I read the bit about stuff voluntarily falling through was at another forum...but I lose track.....so much info its hard to keep straight. Im picking a pound of worms up in the am and will start them in a tote bin that I constructed from plans here. This will give me time to work with the worms...let them breed a little ( I hope ) and understand the system before I go hog wild. Wierd...I cant sleep as I lay there working out plans all night in my head. Think I have the harvesting mechanism worked out...should be low tech..low cost and effective ( we will see ) thanks all for the input. I will have more questions as I move along.......

dave

So I have done a bit of research and thought I would post what I have learned. It would seem that the reason the castings dont fall to the bottom is a matter of tension. As the VC compacts, there is a natural occuring tension that is formed between the VC and the side of the bin. Wood that has a grain in it increases the amount of tension and a smooth plastic surface will have less, but still have tension all the same. It was suggested to me that in order to mitigate this, the inner walls of the bin should be canted slightly so that the top is narrower than the bottom. In my design, I have incorpoated a 1" cant over 2'. If this proves effective....I will repost...but as my bin is on the drawing board still, well it might be awhile.

Would be interesting info for the group as I don't think it's been tried before and it seems a not uncommon problem, especially in smaller FT systems.

Good luck.

Is the solid matter in the bin displaced by the air chambers created by the burrowing worms causing expansion of the entire mass?

"Is the solid matter in the bin displaced by the air chambers created by the burrowing worms causing expansion of the entire mass?" I don't know about the expansion of the universe, but when the stuff in the flow through does decide to fall it does so all at once. Plus the worms like to hang out at the edge of the universe between the plastic and the material and glue the two together with their vermiglue. This is an attempt to stop their universe from expanding.

If only humans had the ability to produce vermiglue we could keep our universe from expanding! Of course with the disappearing ozone layer I'm not sure what we could stick our vermiglue to.

It certainly wouldnt be Cheney or GWB.....nothing seems to stick to those two...lol

"Is the solid matter in the bin displaced by the air chambers created by the burrowing worms causing expansion of the entire mass?"

Universe aside ;). I'd say yes, stuff has to go somewhere. But then it also might be collapsing other worm tunnels. Also the stuff in general shrinks as it gets eaten. I will say it's another good thing about having a drier bottom. If it's muddy, those tunnels definately collapse, if it's drier might stay open and make it even more breathable.