Melon Development

• Depending on the variety, vines need 75 to 90 days of warm to hot weather from seed germination to harvest. Cool and rainy weather, with temperatures below 80 degrees, slows development of melons and sugars in their core. Overly dry soil slows melon development. If the plant withers, the connecting stem supplying carbohydrates and water to the growing melon can die. Shriveled or dry stems on watermelons means no further resources are going into the melon.
  
  

Determining Ripeness

• Although many people claim thumping the melon is the ultimate test, with a dull thud meaning prime ripeness, it's inconsistent. A better way is watching the watermelon's stem. If it remains intact, green and plump, the melon is still developing. Once the stem shrivels and the bald pale-green-to-white spot on the melon's underside changes to creamy or pale yellow, it's ripe. The green skin also changes from glossy to a dull matte.
  
  

Storage

• Under-ripe watermelons do not further deepen their flesh color or sweeten their juices. Overripe melons begin degrading and become less palatable. Ripe watermelons keep for up to two weeks if uncut and placed where it is between 45 and 50 degrees. It's better to keep ripe, uncut melons at room temperature and refrigerate them just before eating. Once sliced open, covering the melon with cellophane or plastic to prevents desiccation. Place cut melon in the refrigerator for no more than three days.
  
  

Gardening Insight

• Watermelons grow best in full-sun settings in hot conditions with nighttime temperatures 60 to 70 degrees, and daytime temperatures between 80 to 90 degrees. In high latitudes or mountain elevations, the summers are not very warm and the frost-free growing seasons short. Grow early or short-season watermelons in those condition. These types need no more than 75 days in the garden. Mulching the garden with black plastic helps warm the soil and air around the watermelon vines.