Certified GKH Gardening Expert
No, but they will provide better texture to help the roots grow properly. Worm castings aren't very high in nutrients. The NPK values are near zero.
Worm castings provide beneficial microbes more than anything. This article will help you to understand the role of worm castings in soil:
Before adding anything into soil, you will need to test it to see what it is lacking. These articles will help you to do so: