Step 1Combine the zucchini, onions, celery and peppers in a large glass mixing bowl. Cover with cold water and stir in the salt. Let stand at room temperature overnight. Drain and rinse 4 times in cold water.
Step 2Dissolve the cornstarch in 1/2 cup of vinegar and add to the vegetables along with the remaining 2 cups of vinegar, the sugar, nutmeg, turmeric, pepper, jalapenos and garlic.
Step 3Place the mixture in a large pot, partially cover and simmer 15 minutes.
Step 4Meanwhile, bring a large pot of water to a boil and sterilize the jars and lids, about 5 minutes. Turn off the heat, but leave the jars and lids in the hot water until you're ready to use them.
Step 5Fill the jars with the mixture to within 1/2 inch of the top, being careful to keep the jar rim clean. Cover each jar with the flat part of the lid and tighten the ring around it.