Add mixed berries, sugar, lemon juice and salt to a medium saucepan. Stir and begin to cook the berries on medium heat.

Bring the berries to a boil, then reduce the heat to medium-low. Simmer for 20-25 minutes, stirring occasionally.

Once jam has thickened, remove from heat and transfer to a mason jar or glass container to cool. Once cool, add a tight lid and place in the fridge. Enjoy for up to 3 weeks!