4 cups chopped zucchini, cored and seeded
2 cups chopped onions
2 cups chopped red bell peppers, seeded
1½ Tbsp. pickling salt
1 cup sugar
2 cups cider vinegar
1 tsp. celery seeds
1 tsp. yellow mustard seeds
4 thin slices fresh ginger, divided
In a large bowl, mix the chopped vegetables with the pickling salt and pour into a colander. Place the colander inside the mixing bowl and allow the vegetables to sit 30 minutes to season and remove excess water.
Meanwhile, bring the sugar, cider vinegar, celery seeds and mustard seeds to a boil in a stainless steel or nonreactive pot over high heat.
Thoroughly rinse and drain the vegetables, then add them to the brine and simmer 5 minutes. Remove from heat and set aside.
Place 1 slice fresh ginger in the bottom of 4 sterilized, 1-pint canning jars. Use a wide-mouth canning funnel or ladle to transfer the hot relish into each jar, leaving ½ inch of space. Place a sterilized mouth lid on top of each jar and secure it with a sterilized band. Do not twist it tightly, just enough to keep the lid in place.
If using the water bath method, fill a stockpot with enough water to cover a 1-pint canning jar. Bring the water to a rapid boil over high heat. Carefully place the jars in the stockpot, cover, and boil 10 minutes to seal them. Use canning tongs or regular tongs to carefully remove the jars from the water and let cool.
If using the pressure cooker method, place the canning rack at the bottom of the pot, then add the jars. Fill the pot with 3 quarts cold water and 2 tablespoons white vinegar. Secure the pressure cooker lid and place it over high heat. When the pressure gauge reaches 11 pounds, lower the heat to medium. Let cook 15 minutes, watching the pressure gauge and adjusting the temperature as needed to maintain 11 pounds of pressure.
Turn off the heat and let the pressure cooker cool. Once the pressure gauge returns to 0 pounds, remove the lid, gently remove the jars and let cool under a clean towel.
When they are completely cool, check if any of the lids still pop up and down. These quarts did not seal and should be refrigerated and used within 2 weeks.
Tighten the bands on the jars that formed a seal and store in a dark place. Relish should rest at least 3 weeks before eating. Sealed relish will keep for several years.