Ingredients
8 cups (1.9 liters) diced yellow squash
2 cups (475 ml) diced onion
2 red bell peppers, diced
2 green bell peppers, diced
3 tbsp salt
3 cups (710 ml) white sugar
2 cups (475 ml) vinegar
2 tsp celery seeds
2 tsp whole mustard seeds
6 (1 pint) canning jars with lids and rings
Directions
Step 1
In a large bowl, combine the squash, onion, red bell peppers, and green bell peppers. Sprinkle with salt, toss to combine, and let the vegetables drain for 1 hour. Discard the drained juice.
Step 2
In a large pot, combine sugar, vinegar, celery seeds, and mustard seeds. Bring to a boil over medium heat, stirring to dissolve the sugar. Add the squash mixture and return to a boil. Cook until the vegetables are tender, about 15 minutes.
Step 3
Sterilize the jars and lids in boiling water for at least 5 minutes. Pack the hot squash relish into the sterilized jars, leaving 1/4 inch of space at the top. Use a thin spatula to remove any air bubbles, wipe the jar rims, and top with lids. Secure the lids with rings.
Step 4
Place a rack in the bottom of a large stockpot and fill halfway with water. Bring to a boil, then carefully lower the filled jars into the pot using a holder. Leave a 2-inch space between the jars. Pour in more boiling water if needed until the water level is at least 1 inch above the jar tops. Bring the water to a full boil, cover the pot, and process for 10 minutes (or the recommended time for your area).
Step 5
Remove the jars from the pot and place on a cloth-covered surface until cool. Press the top of each lid to ensure a tight seal. Store the jars in a cool, dark area.