Watermelon jam is unusually tender and refreshing. More details about watermelon jam... If you're left with watermelon and don't know what to do with it, keep it tasting fresh and make watermelon jam. There are two types of recipe for watermelon jam: jam from watermelon crusts, recipe from watermelon pulp. Watermelon jam from pulp is very tender, and jam from watermelon crusts is somewhat reminiscent of candied fruits. All you need to make watermelon jam is watermelon, sugar, citric acid, vanillin. But you can also make a jam of watermelon and melon, apples or orange.