Wash the watermelon thoroughly and remove the green outer skin from the rind, leaving just the white part. Dice the rind into 1-inch cubes.

Soak the diced watermelon rind in fresh water for approximately 30 minutes.

Cook the watermelon rind with 1 cup of water and ½ teaspoon of salt in a saucepan until boiling, then simmer for 30 minutes.

Strain the mixture through a fine-mesh sieve into a bowl, discarding the solids.

Return the strained liquid to the saucepan and add sugar, lemon juice, and pectin. Stir and bring to a boil again.

Cook for about 10 minutes until the jelly thickens and reaches a gel-like consistency.

Pour the hot jelly into sterilized jars, leaving about ½ inch of headspace, and wipe the rims clean.

Seal the jars and process them in a boiling water bath for 5-10 minutes to preserve the jelly.

Cool the jars completely at room temperature and ensure proper sealing.