how long does watermelon keep
Watermelons, depending on it's condition and how it's kept, may or may not last long. Here's a site to give you a better idea about it: http://www.whataboutwatermelon.com/index.php/2009/05/ask-the-experts-how-long-will-my-watermelon-last/
After being cut open, watermelon will keep for 3 to 5 days. Keep the watermelon refrigerated to help keep it crisp.
Watermelon will stay good for about 7 days after it is cut. Watermelon should never be kept in the freezer.
Fresh watermelon can be kept whole and uncut at room temperature for 7 to 10 days. Once cut, it should be stored in the refrigerator and will stay fresh up to a week.