1. Prepare the Vegetables:
In an very large bowl or food-safe container, combine the chopped green tomatoes, onions, and green bell peppers. Sprinkle the salt over the mixture and toss to combine. Cover and let stand at room temperature for 8-12 hours, or overnight. This step draws out excess liquid and helps keep the relish crisp.
2. Drain and Combine:
The next day, drain the vegetable mixture in a large colander, pressing gently to remove the liquid. Transfer the drained vegetables to a large, heavy-bottomed stockpot.
3. Add Remaining Ingredients:
To the pot, add the chopped green chile peppers, white vinegar, sugar, and prepared horseradish.
4. Prepare the Spice Bag:
Place the cinnamon, allspice, and cloves onto a square of cheesecloth. Tie it securely with kitchen twine to create a spice bag. Submerge the spice bag in the vegetable mixture. (This allows the flavors to infuse without leaving gritty spices in your final relish).
5. Cook the Relish:
Bring the mixture to a boil over medium-high heat. Reduce the heat to a steady simmer and cook for about 15 minutes, stirring occasionally, until the vegetables are tender but still retain some texture.
6. Jar and Seal:
Remove and discard the spice bag. Carefully ladle the hot relish into sterilized jars, leaving ½ inch of headspace. Wipe the rims clean, place the lids on top, and screw on the bands until fingertip-tight.
7. Process for Shelf-Stability (Optional but Recommended):
For safe, long-term storage at room temperature, process the filled jars in a boiling water bath for 15 minutes. Remove the jars and let them cool completely on a towel-lined counter. Check that the lids have sealed (they should not flex up or down when pressed).
8. Store and Mature:
Store the sealed jars in a cool, dark place for at least two weeks before opening to allow the flavors to fully develop and mingle. Properly sealed jars will keep for up to one year. Once opened, refrigerate and consume within a month.
