Dennis, I have trouble with melons dark spotting when I have to water them in late summer. Melons really don't like to be watered. The early spring rains soak the ground and produce a large melon plant, but when the melons start to grow, we always had luck in dry sandy soil on my dad's place in Denton where the melon roots could go deep and find the proper amount of moisture. The best melons I can remember were never watered. In my garden, I'm guilty of over-watering. I'm sure the uneven moisture is part of the problem. I can't believe our soil here is low in calcium, but I guess it could be. When I first put my garden in, Bird reminded me to get a soil test. Now that I have the final mix of soils, that's probably what I should do. I grow great cantaloupes, but not-so-good watermelons.