Sanitize your canning equipment, including jars and lids, by placing them in a water bath canner filled with boiling water for about 10 minutes.

Wash your peaches and blueberries thoroughly. Peel, pit, and chop the peaches into small pieces.

In a large pot, combine the chopped peaches, blueberries, lemon juice, and water. Stir gently and bring to a boil.

After boiling, reduce heat to a simmer for about 10 minutes, stirring occasionally.

Gradually stir in the sugar and salt until dissolved. Add any spices in a spice bag.

Bring the mixture back to a rapid boil, stirring constantly until it reaches 220°F.

Perform the plate test to check if the jam is ready by spooning a small amount onto a chilled plate.

Ladle the hot jam into sterilized jars, leaving a ¼-inch headspace.

Process the filled jars in a boiling water bath for 10 minutes.

After cooling, check the seals by pressing the center of each lid.