Here are a couple of ways to harvest castings from your worm bin. 

Dump and Sort Method - Worms don't like light!

1. Lay out a piece of plastic, tarp or old bed sheet in a bright location or use a lamp.
2. Dump bin onto #1
3. Create many cone shaped piles
4. Shine light onto cone shaped piles
5. Skim off top layer of castings
6. Skim off another layer of castings
7. Repeat steps #3 and #4 until all you have left at the bottom are worms

The Great Migration Method

1. Push all of your castings to one side of your bin
2. Fill empty side with new bedding and food
3. Wait for it....
4. Wait for it.............
5. Repeat steps #3 and #4 until all worms have migrated over the new food source.
6. This method takes a couple days to a couple weeks depending on your worm herd and the amount of unprocessed food in the old side.

The Flow Through

1. Build a flow through bin or purchase one and follow the instructions.  See Worm Bin Construction for DIY instructions

The Great Shake

1. Make a screen to sort out the worms and the castings.   1/4" screen to screen out the worms and food debris.
2. Second screening with 1/8" screen to screen out cocoons and create beautiful castings.