Multiple crosses of closely related diploid and tetraploid plants are made until the fruit produced consistently expresses the selected traits. The plant breeder or the seed grower usually does the naming of a new variety. If the seed grower wishes to name the variety to identify that variety as their brand, this may be acceptable if there is an exclusive license or the company may assign a name and license the right to produce and sell the variety. If multiple companies have the rights to the same variety, then there may be geographic limitations on marketing areas. With the timing of planting based on climate and grower preference, seeds are initially germinated in green houses and small plants are set out.
Watermelons require a relatively long growing period and prefer hot, rather dry weather.
They do not thrive in heavy, wet soil. By rotating locations that include different climates, it is possible to grow two generations in one year, but typically only one generation can be tested each year. When plants are set in the soil, it takes approximately 50 to 95 days before flowers are produced. Bees begin active pollination when the temperature reaches 65 degrees F or higher. The appearance of flowers changes over the course of days and selecting a newly opened flower from one that has likely been pollinated during a previous day is not difficult.