Wash and prepare the vegetables. Place them in a large pot and cover with water. Boil for 5 minutes.
Place an onion slice and the salt in each jar.
Ladle vegetables and liquid into hot, clean jars, leaving 1 inch of headspace. Use a bubble freer or plastic knife to remove any trapped air bubbles. Add more liquid if neccessary to maintain 1-inch of head space. Wipe jar rims and threads with a clean, damp cloth.
Cap, seal, and process in a pressure canner for 90 minutes at 11 pounds of pressure in a dial-guage canner or at 10 pounds in a weighted-gauge canner, adjusting for elevation if more than 1,000 feet above sea level.
