I am planning to amend my clay soil with lots of organic material and large granite grit. Will the granite grit harm earthworms? I don't intend it to help in earthworm digestion; I just want it to be benign.
large granite grit and earthworms
No issues with this. I have worms living in the gravel paths surrounding my raised beds. In other areas which I have amended with grit, there are plenty of worms.