1Place the peas and water into a large soup pot over medium heat; bring to a boil, boil for 2 minutes, and set aside off the heat to cool for 1 hour.
2Place the ham bone into the pot with the peas, and stir in onion, marjoram, thyme, garlic powder, and salt; bring to a boil over medium heat, reduce heat to a simmer, cover the pot, and simmer for 2 hours, stirring occasionally. Remove the ham bone, and cut as much ham as possible from the bone; chop the ham, and return to the soup. Stir in celery. Discard ham bone. Bring soup back to a simmer, and cook for 45 more minutes, stirring occasionally. Season to taste with salt.
Footnotes
Easy Cleanup
Try using a liner in your slow cooker for easier cleanup