I have two yellowbaby watermelons growing in my greenhouse. they don't seem to be getting much bigger now but how can I tell when they are ripe?
I know with other melons the stem starts to come away from the fruit when they are ready to eat but am not sure if this is the same for watermelons.
On the other side of the vine from where the stem from the fruit joins the vine you will see a 'pigtail'. When this is brown and withered the fruit will be ripe. This is the most reliable indicator that I know of.