My worm farm is sitting there full of worm castings and I had no idea how to get it out without getting handfuls of worms too! I didn't want to lose all my worms, and they had done such a great job, I thought I'd better do some internet research about it.
Some people suggest an isolation method when you use a single bin system (like I do) where you put all the food on one side and all the worms will go across to that side, leaving the other side free to harvest your castings. This pic was from Vermiculture Blog.
At the moment this is my worm bin:
So I could try the isolation method. However, I won't be able to get the eggs or the younger worms, and I'd lose all of them into my garden. And it takes WEEKS to do that.
Another method is to use the hessian and pile the castings on top of it (and a container beneath). The worms will bury away from the light and the castings will remain. Another method where I would lose the eggs, but at least I could get a good load of castings and it would be quick.
A variation on the hessian filter is to make cone shaped piles and keep shaving off the outside of the pile as the worms dig into the pile. This way you could save a few more eggs. I read about it (and scabbed these pics) from here.
The last method is the empty it all out and sort through it with your hands method. As long as you don't mind getting dirty and sorting through all the castings by hand and picking out the worms. I think it's a bit long though.
I just need some time on the weekend and I will be able to get some castings so I can work with them for my plants. For seeds I am supposed to put the seeds on top of it and then cover and then work the casts into the top soil once a month.
For seedlings you are supposed to put the roots onto the castings and then cover them. Or you can make a mix of 1/4 castings, 1/4 peat moss, 1/4 leaf/hay litter/ 1/4 sand or garden soil (for drainage).
I'm looking forward to finally using some castings. I'm trying to make a second worm farm, so maybe I'll be able to get a little more usage out of my worms! It's hard enough now trying to find enough scraps for the worms AND the compost AND the chickens.