Q.My Worm Bin Seems Too Moist – Harvesting Castings Almost Impossible.
I live in South Africa. I have had a worm bin for many years and find it an excellent way to get rid of kitchen/vegetable scraps. Although the scraps break down quickly and successfully the castings remain very wet. The consistency remains muddy and pasty; it is very sticky and when I do dry it out it hardens into stoney clumps. Putting that dried matter through a garden sieve is labourious and not very successful. What am I doing wrong and how can I improve matters?

Certified GKH Gardening Expert
You may be adding greens but no browns. Besides fruits and vegetables you need to add the browns such as newspaper, egg cartons, copy paper, and cardboard.
This article tells more:
https://www.gardeningknowhow.com/composting/vermicomposting/care-and-feeding-of-worms.htm