40 seeds. 88 days. Citrullus lanatus. Annual.
 
Watermelon 'Charleston Grey' has large, elongated fruits that can weigh 20 to 30 pounds. The rind is light green and the flesh is pleasantly red and sweet. This South Carolina 1954 open-pollinated watermelon was developed to have a hard rind for storing and shipping. It is also disease resistant.
 
You can tell when a watermelon is ripe because the rind turns a duller color. The tendril near the fruit also turns brown and dries up.
 
Sowing Watermelon Seeds: 
 
Sow seeds outdoors after the last frost date when the soil is warm, 1/2 inch deep. Sow in hills that are spaced 5 feet apart and thin to 3 plants per hill, or sow in rows 2 feet apart. Full sun.