Your old farmer friend might be right! Watermelons like soil a little on the acidic side, a pH of 6-6.8 at the highest down to 5 at the lowest. Test your soil before you add any more amendments. The leaves produce sugars that help your watermelons to ripen. If they are dying off prematurely due to disease or insects the fruit doesn't stand of chance of ripening. Nothing is more disappointing than cutting into a melon you have been growing for months only to find that it is not ripe! Some tests, other than the thump test (which I have never perfected) are:
The tendril closest to the fruit will turn brown.
The fruit will twist off easily from the stem.
The white spot on the bottom of the fruit will turn yellow.
The rind of the melon will be dull green.
The vine nearest the end of the fruit will be cracked and brown.
The fruit should smell sweet when sniffed.
They should have a slight give when squeezed.
Your old farmer friend might be right! Watermelons like soil a little on the acidic side, a pH of 6-6.8 at the highest down to 5 at the lowest. Test your soil before you add any more amendments. The leaves produce sugars that help your watermelons to ripen. If they are dying off prematurely due to disease or insects the fruit doesn't stand of chance of ripening. Nothing is more disappointing than cutting into a melon you have been growing for months only to find that it is not ripe! Some tests, other than the thump test (which I have never perfected) are:
The tendril closest to the fruit will turn brown.
The fruit will twist off easily from the stem.
The white spot on the bottom of the fruit will turn yellow.
The rind of the melon will be dull green.
The vine nearest the end of the fruit will be cracked and brown.
The fruit should smell sweet when sniffed.
They should have a slight give when squeezed.