I can't say for sure - but black sounds like mold and yes, the excessive rain and lingering humidity would explain that. You are further north, but nearly all gardening ceases by late May in the southern part of the state - especially those plants most affected by fungal disease. Check the UF vegetable gardening sources and find the best time to plant and the hardiest varieties for your area.

Might be blight, but there are a number of watermelon diseases. I agree UF's site is a good resource.

Here's an article on watermelon diseases from there:

http://edis.ifas.ufl.edu/pg060

Thanks Sonni and Carol. I'll check out the UF sites and send them to my son as well.

Could it be blossom end rot? The 3 that have grown so far all started rotting in the same place. I told my son that he should have the soil checked to determine if it has enough calcium.

Picture...finally

Thanks!

Rhonda

Crush one tumms,add to a gallon of water and water plant.

Thanks Glenn! I have forwarded your info to my son.