Hubba, Hubba Watermelon

I'm confused about when to pick watermelons because my one surviving vine has them growing at all stages - older ones and younger ones.  I thought I had it all figured out.  Pick them when the tendril closest to the fruit has dried.  That worked great for the first three that I picked.  They were nice and sweet and not too ripe.  But now I'm second guessing myself.  With these later ones, they just keep growing and growing and the tendril is staying green so then I wonder if maybe the season isn't right and it's too late in the summer for watermelon and maybe they aren't ripening the same way.  Then there's the dilemma about how much to water.  I read that if a watermelon in the last stages of ripening gets watered too much, it won't be sweet.  But there are younger ones on the vine that need watering.

I finally picked this one when the tendril was half dried.

It was 34.4 pounds.  Mostly sweet.  I couldn't tell if it was on the verge of overripe or on the verge of underripe in some areas.  I had to freeze part of it because it wouldn't all fit in my giant rubbermaid container.