Recipe yields 3-4 pint jars.

Make the relish:

• If you have a food processor you can just toss roughly chopped zucchini, onions, and peppers into the bowl of the processor and pulse until they're a good size. I like mine in about 1/8 - 1/4" pieces. If you don't have a food processor, just chop them finely by hand.
  4 cups zucchini, 2 cups onion, 1 red bell pepper, 1 jalapeno pepper
• Combine chopped zucchini, onion, peppers, and salt in a large bowl, stirring well. Chill overnight.
  1 1/2 teaspoons sea salt
• Place in a colander to drain; rinse thoroughly and drain again.
• Transfer to a large stock pot and add remaining ingredients; bring just to a boil. Simmer for 10 minutes. At this point, the relish is done. You can just put it in jars and then in the refrigerator to use right away or give as gifts.
  1 1/2 cups sugar, 1 1/2 cups apple cider vinegar, 1 1/2 teaspoons ground turmeric, 2 teaspoons mustard seeds, 1/2 teaspoon pepper, Pinch nutmeg
• If you'd like your relish to be shelf stable, you'll need to process it.

Prepare for Canning

• Wash the jars you'll use, making sure each is clean and free of nicks in the rim, which could impede sealing.
• Wash the lids and rings in hot soapy water. (If you're using non-Ball brand lids, prepare as suggested by manufacturer.)
• Place empty jars in a canning pot or large stock pot with enough water to cover by an inch or two, cover pot, and set on high heat. It can take awhile for the water to heat, so get it started when you start heating the relish.

Canning the zucchini relish:

• Remove empty jars from canner, draining water back into pot.
• Ladle hot relish into pint or half-pint jars, leaving 1/2" head space. A canning funnel makes this easy.
• Use a bubble remover or plastic knife to remove any visible air bubbles. 
• Wipe jar rims to remove any relish that may have spilled. A clean rim is essential to a good seal.
• Set jar lids in place. Screw bands on finger tight.
• Use a jar lifter to lower jars into hot water in canning pot. Water should cover the top of the jars by two inches. The water will cool somewhat in reaction to the addition of the jars. Return the water to a simmer and set the timer.
• Process for 15 minutes 0-6,000 feet altitude; 20 minutes over 6,000 feet.
• Allow jars to cool overnight.
• Check for seal: the lids should feel solid and slightly indented. If they flex, that are not shelf stable and should be refrigerated and used first.
• Wash jars, remove rings, and store in a cool, dry place for a year.