Dawn, I sympathize with you - there is nothing better than a good home grown melon. Perhaps it will help to have a soil sample tested. This is a service provided free through your county extention service throughout NC.

Here is a link that might be useful: Link to County Extension Offices in NC

If it rains a lot in the couple of weeks before harvest it can dilute the flavor. We grew ambrosias two years in a row and the difference in the dry year and wet one was surprising.

I don't know how the melon farmers do it. I have tried every trick in the book and mine never taste as sweet as storebought. Even canteloupes.

I was always told that long hot summers make the best watermelons but I gardened in Oklahoma most of my life and it is way hotter than here. My dad's garden has only produced one crop of sweeter-than-store-bought melons in his entire life!!

I know that some local farmers make it happen but I have yet to learn what the trick is.

Well this isn't going to help much but DH's grandfather used to grow excellent melons. DH doesn't know how his grandfather did it. DH thought his grandfather grew the variety "Hale's Best" and that the melons tasted best in a dry year. His grandfather gardened in red clay in Wake County.

I have a feeling that ralph is right. Certainly rainfall will dilute the sweetness because strawberry farmers have to deal with this every spring but tasteless melons?
I only grew melons one year and let them stay on the vine until they positively perfumed the air til I picked them. It was really rich loam with regular watering and they were almost too sweet.
Leaving them on the vine may not be the answer either because we've all found hard as rock melons at the store and they've ripened to sweet flavor.
I'd still have the soils checked.

Yes, the pH could be too low. Our first year here we grew tomatoes in our unamended loam in a field near the house (pH 5.5) and the tomatoes tasted terrible until we added lime.

I believe I read that phosphorus will sweeten melons. You might do an internet search and see what you can find.

Pam