That is a good question and I hope we see a good answer from some of the experts. Currently the assumption I am working under is once it looks like something I would be willing to have visible in my flower pots, then it might be ready for use. Granted, I'm doing my best not to have any visible soil in my gardens anymore and mulching everything I can but if the soil were bare... You get the picture I hope.

Anyway, I second the question. How does one know when it is time to harvest?

Well,does it look like good RICH compost.Does it smell earthy and not nasty?
If there is no visible evidence of garbage other than an few small pieces of eggshells then it is ready. Be sure to heap it up and expose to light. Then after 20 minutes scrape the top and set aside,the worms will go to the bottom.You may want to set aside the newly harvested castings and keep them moist in case there are eggs and babies. Give them a few weeks and repeat,removing any new worms and adding them back to the bin. Then start to use the castings.

I don't worry about "done", I harvest everything when I can use it .... and if there's a few laggard worms and/or cocoons [you won't avoid them], they go in the garden too ... vermicompost is compost, organic material on it's way to being soil humus, doesn't need to be "pretty" or a certain texture, or contain zero recognizable material, although if there's not much visible veg scrap or paper/leaves/whatever bedding, then that can tell you it's good to go

Bill

Here is my question....Will it have the texture of finished compost (as in the type of compost from a compost bin) when it is finished? Soft and crumbly, though slightly moist?

I have had worm bins with my class for several years, and only once did it look like rich soil or compost at the end (the kind that I wouldn't mind putting my hand into), and that was when the only thing we put in for the most part was coffee grounds - and I was starting to think that the coffee grounds were a good part of what I was thinking was finished compost. The other times, the whole thing looks more like "mud" than what I get out of a compost bin (the type I would definitely not want to put my hand into). On top of that, there reached a point where the worms were no longer interested in their bedding; it was like all they wanted was more veggies.

Just wanted to bump this up in hopes of a response.

To add to my last point, aside from looking a bit like mud (not the nice compost looking stuff I was expecting), I still have pockets of bedding in there. I would say a good 90% of the bedding is no longer there, but 10% is clearly visible. I have used the shovel to move it a round a bit, but it is still slow-going. So, to recap:
1) I have many, many more worms than I did in June when the bin started.
2) They are eating everything I put in.
3) BUT they are leaving some of the bedding.
4) The texture of what is in the bin isn't very soil-like, or what I imagined it would be. It looks a bit "muddy".

Any thoughts?

1) That is good. It sounds like things are moving along fast for you.
2)That is good too.
3) You are unlikely to get 100% worm castings without sacrificing your worms. So either you will have some bedding left in it, or your worms will have a very hard time surviving to be transfered to new bedding.You might pull aside all the old material a bin and put some new bedding in just one end so they have a place to relax out of the mud. A little bedding out in the garden isn't going to hurt anything.
4) Remember, worm casts are worm poop. They are likely to be a bit wet until they dry out. Mud is usually just wet soil. You might harvest a little bit and see what it looks like as it drys out some. Or perhaps leave the cover open and let the top layer dry out some.

We started our bin in June too and I've started shifting the worms over to the empty end so I can harvest the old end sometime in the near future. My bin looks like bits of mud mixed with paper too. Luckily, I'm not too squeemish and willing to stick my hands in to fluf the lower levels of the bedding or not much bedding as it is now.

vermicompost and bin compost are way different things, and as tclynx sez, it's worm poop really, so it will be "muddy", otherwise the worms wouldn't thrive, their bodies are like 80% water and because they breathe via the moisture on their skin, require a pretty wet situation to avoid suffocation

and yes, the nice crumbly stuff made with coffee grounds was ...... coffee grounds, which provide a nice texture but don't really break down to a size worms can do anything with

remember that worms don't jog around the bin looking for lunch, they simply eat their way along slowly with big grins, if they miss a few tidbits they won't go back for them .... also, while they will happily re-ingest the castings for weeks or months, fresh decomposing material is more attractive

all meaning the "mud" is ready to harvest, have the kids pick out the cocoons, hands are washable :)

Bill

Hi there,

Im no EXPERT, but thought I should add my two cents worth.

I have a tiered system, and it is pretty obvious when the castings are ready. On the lowest layer most of the material added has gone, and things look.... aerated. The castings are lumpy and round and remind me of visiting the beach and you see where the little crabs have dug burrows and there are the little round balls of sand left on top. It looks nice and fluffy.

Because I have a tiered system, when the bottom layer is mostly castings the worms generally migrate to the second layer. They cant survive in just castings with no new food! So I can tell its time to harvest when there are heeeeeaps of worms in the next layer up, but only a few in the bottom layer. I don't worry about trying to save them, it goes in the garden/pots whatever, and they can live in there from now on. If you have a mature worm farm, it should have self regulated to a certain population by now anyway. So the loss of a few worms will do no harm and they will reproduce to cover the loss.

If you system is not a tiered one, I do recall a book by permaculturist Jackie French. She used a double sink as a worm farm. When she wanted to take the castings she would turn on a slow slow hose in the sink. The worms would come to the surface to escape the water and then she would sweep them all off into the second side of the sink and start afresh.

Another way to harvest if you have a single bin is to feed only on one side of the bin for a week or two. Then if there is no food left on the old side, the worms will migrate to the new food and you can remove the castings.

Thanks for the input.

We are going to harvest this week. Here is what I am going to do to make it fun for the kids:
1) I am going to rope off the last three inches on each side of the bin. Then I will divide each of those section in 2, thus giving me four sections on each side - and a while big open space in the middle.
2) I am dividing the class into four groups, and each group will get one of the roped off areas.
3) Their goal today will be to create a food mixture that will lure the most worms over to their square. I have a ton of kitchen scraps for them to choose from. Each group only gets to fill one small Dixie cup, though, so they have to choose wisely.
4) We'll bury their little recipes right in their square. Then we wait.
5) In two days, I will scoop out whatever is in each square and let the kids count how many worms they attracted.
6) The hope is that we will pull most of the worms away from the "open" middle and into our roped off sections. Then I can just scoop that away, pick off any last stragglers and then refill with fresh compost.

Sound like a good idea?

rutgers 1,
It sounds like a good idea but I think it will take longer than a couple of days for the worms to move out of the "open" area. It usually takes a couple of days for the new food scrap additions to become appealing to the worms in my experience. Also, the "open" area probably still has lots of yummy bacteria that the worms are eating.
I have a large bin that we had originally only been filling one half of. Not too long ago the contents started looking like they might be harvest-able soon. I put bedding in the empty half and started adding food over there over a week ago but most of the worms are still in the original half of the bin. I figure it could take quite a long time for them to decide they don't like living in mostly castings anymore. I'm sure eventually we will be picking worms out of castings as we harvest.

I harvested them yesterday. Here are my observations:
1) My plan outlined above actually worked pretty well. The sides were packed with worms.
2) There were still a ton in the center area.
3) The best way I found to separate things was to point the bin into the sun and lightly skim the compost off the top. It took about 30 minutes, but worked well. I left the bottom inch in there since there were so many worms and I figured I could use it to start the new bin.

I really want to get/build a better bin. I just have a plastic tub with some holes drilled into the top. Drainage is obviously bad. I know others said that some paper left over is normal, but think I would have had a better end product had I had the optimum conditions. The tiered systems really intrigue me. Our school is in the process of applying for a grant for one of them.

I found that the corners and areas around the sides in my bin seem to be very well digested, almost 100% castings while the top and middle have a higher % of undigested paper/cardboard. I'm going to take a while till actually harvesting, we have a large bin and had started out only using half of it so I'm going to try and let most of the worms mirgrate over to the new half as I am only feeding over there now. This way I hope to let lots of new worms hatch before harvesting the castings.