Start by preparing the vegetables. Peel and finely chop the onions, shred the cabbage, and dice the green tomatoes and bell peppers. Place all of these ingredients into a large bowl and mix to combine.
In a medium saucepan, heat the salt, sugar, mustard seed, celery seed, and turmeric over medium-high heat. Stir constantly until the sugar is dissolved and the spices are fragrant about 5 minutes.
Add the white vinegar and water, stirring until combined. Slowly pour this mixture over the vegetables in the bowl, making sure to coat them completely.
Stir the chow-chow together so that all of the ingredients are evenly mixed. Transfer to a large container with a lid and let cool at room temperature for at least 4 hours.
Enjoy your flavorful Pioneer Woman Chow-Chow!