Inspect canning jars for cracks and rings for rust, discarding any defective ones. Immerse in simmering water until salsa is ready. Wash new, unused lids and rings in warm soapy water.

Combine peaches, jalapeño, onion, bell pepper, cilantro, vinegar, garlic, cumin, and lime zest in a large saucepan. Mix together pectin and 1/4 cup sugar in a small bowl, then stir into peach mixture in the saucepan. Bring to a boil. Stir in remaining 3 1/2 cups sugar. Boil for 1 minute, stirring constantly. Remove from heat and stir for 5 minutes.

Pack salsa into hot, sterilized jars, filling to within 1/4 inch of the top. Run a clean knife or thin spatula around the insides of the jars to remove any air bubbles. Wipe the rims with a moist paper towel to remove any residue. Top with the lids and screw the rings on tightly

Place a rack in the bottom of a large stockpot and fill halfway with water. Bring to a boil and lower jars 2 inches apart into boiling water using a holder. Pour in more boiling water to cover jars by at least 1 inch. Bring to a rolling boil, cover, and process for 15 minutes.

Remove the jars from the stockpot and let rest, several inches apart, for 12 to 24 hours. Press the center of each lid with a finger to ensure the lid does not move up or down. Remove the rings for storage and store in a cool, dark area.