Add oil and onions to the heavy bottom pot. Saute with garlic for a few minutes, until fragrant.
Meanwhile wash turnip greens with cold water. Cut out stems and chop greens in about 2 inches strips.
Add greens to onions and garlic. Add ham hock, water, salt and pepper.
Close the lid and cook on medium-low heat for about 45 minutes.
Pull out ham hock. Cut all the meat off ad chop it. Put back into the pot and stir.
