18 feet by 18 feet by 4 feet! Is your boy even tall enough to look in that bin? If you're only starting with a pound of worms and you want it to be fun for your son, I wouldn't have the bin more than 1 1/2 feet by 2 1/2 feet by 18 inches or so. That way the worms will be contained and you'll get to see things happening. If you put 1 pound of worms in a huge bin I imagine they'll all get lost and the best you'd be able to see would be like a compost pile. Eventually, the worms would probably move in, but I don't think it would be much fun waiting.

FWIW,
Mariann

Could you make it like a windrow in a box.

Could do the worm bottle experiment

Did you, possibly mean a bin that is 18 inches deep by 18 inches wide by 4 feet long? I'd lay odds that you did, but do tell me if I'm wrong!

Assuming that I am right about the bin measurments, one pound of worms will be just fine for such a unit. While the bin can certainly hold much more than that, they worms will appreciate the abundant space in which to amplify their population at their own pace, you will not need to be as careful to avoid overfeeding, and the system mass will be a good insulator against extremes of heat or cold. Sounds like you're in good shape!

The lateral movement idea you describe in the last paragraph above has been used successfully by home vermicomposters for many years, and the unit you've built would certainly lend itself to such use. If this idea appeals to you give it a try! Know, though, that it is not required, that worms do not need to be kept in close quarters, but breed based on the amount of available food and space. Were you to bed the entire 18"x18"x4' bin and place just two worms in it, they would find eachother and start a food scrap processing dynasty before your very eyes! If they are kept sufficient damp and if the system is adequately fed, one pound of worms, which numbers between 1200 and 2000 individuals of varying ages when the species being discussed is Eisenia fetida, will begin populating that space very quickly.

Go with your gut on how to set up and manage your system, Brad. It sounds as though you're doing just fine!

Kelly S

Big mistake, it is 18" x 18" x 4' sorry about that. Thanks for the replys. I just wanted to double check because it seems a lot bigger than what most here have.

It'll probably be a week or two before we order the worms so I can read up some more to make sure I've got all my bases covered. My boy is excited, not only is he getting a veggy garden he's getting a worm farm. lol

Thanks,
Brad

I like your idea about halving the bin at first. Then, when you want to harvest you can just fill the other half with bedding and let them migrate while the old compost continues to break down. I think 18"x18"x4' would be a really good size for that method of harvesting and starting with 1lb of worms.

Sounds like a great bin!
Mariann