Mulch with straw.
A thick layer of straw around your melon vines not only keeps the soil evenly moist and obstructs weeds from sprouting, it also prevents the melons from direct contact with the soil, further reducing the risk of diseases that may splash up from the soil.
Look for resistant varieties.
Fusarium wilt and bacterial wilt are two prevalent watermelon diseases. The best ways to avoid these diseases, which are typically not curable, is to look for disease resistant varieties.
Pests? A couple.
Cucumber beetles typically prefer cucumbers and muskmelons, but they will occasionally feast on watermelons, too. Insecticidal soap is a safe, effective treatment for most cucumber beetle infestations. If you've endured major cucumber beetle attacks in the past, keep them from getting to your vines with row covers—just be sure to remove the covers when the vines begin to flower so that bees can pollinate them, which is necessary for the plant to set fruit.
Squash vine borer larvae tunnel into watermelon vines, chewing inner tissue near the base and filling the stem with moist, slimy castings. The attacked vines wilt suddenly and girdled vines rot and die. Again, row covers are the best defense, according to Rodale's Pest and Disease Problem Solver.
When are the melons ripe?
Experienced watermelon growers try a lot of tricks to know exactly when the fruit is ready to eat. Here are a few you can try: