Add all the ingredients to your slow cooker, gently stir around the ham hock to incorporate, then cover and cook on low for 8 hours or high for 5 hours. You want it cooked enough so that the peas are softened and the ham falls off the bone.
After the soup is done, carefully remove the ham hock from the soup and shred it off the bone. Then you can roughly chop it up and add it back into the soup.
Store leftovers in an airtight container for up to one week.