Place peppers into a large pot. Add vinegar, water, garlic and onion. Bring to a boil. Reduce heat, simmer for 5 minutes.
Ladle pepper mixture into canning jars, leaving ¼ inch of headspace. Stir jars gently to remove air bubbles. Place 2-piece lids on jars and twist until finger-tight.
Place jars in the rack of a large canning pan. Fill with enough water to cover jars completely. Bring water to a boil. Boil for 10 to 15 minutes. Carefully remove jars and let cool. Refrigerate after opening.
Peppers will keep unopened for a year. Once opened, peppers in the fridge are good for about two weeks.
Recipe courtesy Joyce L. Moore. Photographs by Cassie Tam. For more information about Urban Patch and Moore’s seasonal preserving classes, visit UrbanPatch.org.