Combine all ingredients in a large bowl and toss to combine. Mixture is going to be dry because of all the fresh spinach, almost like a salad.
Put the mixed spinach mixture into a 3 to 4 quart slow cooker (you may need to push it down to get it all to fit, that's OK)
Cover and cook on LOW for 1 1/2 hours.
Open the lid and give everything a stir.
Cover again and cook and additional 1 to 2 hours on LOW till everything is creamy and the spinach has cooked down.
Notes
Because this recipe uses fresh spinach it it will seem like you are stuffing a lot of ingredients into a small crock-pot. Have no fear, the spinach cooks down a lot and combines with all the cheese for a gooey and cheese dip!