Rinse peas, and combine with remaining ingredients in slow cooker.
Give everything a quick stir, and then set slow cooker to HIGH and cook 5-6 hours. If possible, stir it about halfway through. After cooking for 5-6 hours, the meat on the ham-bone should be falling apart.
Reduce the slow cooker to LOW. If your soup seems too thick, add more water at this time.
Using tongs or an extra-large serving spoon, carefully remove ham bone to a plate to cool.When the ham bone is cool enough to handle, remove any ham and return the meat to the soup. Discard the ham bone.
Adjust seasonings to taste.
You can serve this soup immediately; however, we strongly recommend serving it the next day.If you serve split pea soup straight out of the slow cooker, it will be tasty but very thin, with the consistency of thin gruel. This is a normal and expected part of the process. DO NOT attempt to thicken this soup with cornstarch, flour, potato flakes, or anything else!
To serve the next day: Turn the slow cooker off and allow the soup to cool for 2 hours. Stir once and then put the soup into the refrigerator and leave it overnight. In that time, the soup will transform; thickening and melding into a hearty, deliciously satisfying split pea soup.
When you are ready to serve, simply reheat the soup in a large stockpot, or use the Warm setting on your slow cooker to slowly bring it back up to temperature.
The type of ham bone you use will determine the underlying flavor profile of your soup. If you use a honey or glazed ham bone, your soup will be slightly sweeter. If you use a smoked ham bone (or ham hock), your soup will taste more smokey.