I read everything I could on this forum that was posted by some of, what I consider, the greatest watermelon growers. There is a watermelon growing thread that is a joy to read and full of all the methods needed, and great varieties to try. Watermelon Growing
I did what they suggested and added my own twist in starting those plants very, very early. I mean very early, mine are started now and will not go out until June. I do this for two reasons:
1- most often I lose some of the plants, last year I started them later than usual but lost some of the first seeded ones and that set me waaaaay back, too late to start again. So I start some early and seed one plant every week after.
2- I like to get the plant into at least a 1/2 gal to 1 gal. pot and have it blooming when it gets planted in the ground. This way if the plant is set back it is no big deal.
I grafted a couple Orengeglol and they produced fruit earlier, but the ones not grafted also produced fruit albeit, much later. I also put a couple in the greenhouse and found that I had problems with bugs etc., and the ones in the garden also produced, again, later, but they did ripen.
If you search this site you can also find that there are great Watermelon growing threads for each year.