I am trying to grow watermelons for the first time this year. I planted Weeks giant watermelon seeds and the plant has vines about 6-7 feet long. I read somewhere I think that they produce male flowers first and female ones on the ends of the vines after they get so many feet long. Is this correct? I only planted the one plant and I'm getting kind of worried because none of the five vines have had any female flowers yet. I hope I don't need two or more for pollination. Do watermelons usually produce both male and female flowers? Thank you,

Holly