Some make watermelon wine other make watermelon Jelly.
My brother decided he wanted to make water melon jelly, He called sister in Arizona and ask her how to make water melon Jelly? she didn't know but she said look on your computer for a receipt.
Brother did and if you seek you shall fine, he found a receipt 3 cups water melon rind 3 cups water 2 cups sugar. They said to cook to the soft ball stage, all mama's children cook like mama no measuring just guessing. Brother cook the stuff for 2 hours and figured that would be about right. He harvest 2 pints one he sealed and one he put in the fridge for his morning toast.
Morning arrives toast is cooking and he is licking his chops getting his water melon wine no I mean jelly. He put a spoon into the jar and the spoon bent double, the jelly jelled real good! Brother still wants to taste the jell on his toast so in the microwave go the jar and after 2 minutes he puts the bent spoon in again now he has syrup but it doesn't have to be spread on the bread it runs free.
Then comes the taste test. Guess what it had no flavor, just taste like sugar syrup but it was a pretty green color. Brother has two pints of water melon rind Jelly he will sell you cheap.!