Watermelons plants grow best in areas with warm temperatures and long growing seasons, but there are several varieties that can grow in cooler climates. Once you've selected the proper variety for your growing conditions, these plants will require care to stay healthy. Keep a few key points in mind and you will have plenty of sweet, delicious watermelon to serve your family at harvest time.
Start plants indoors about three weeks before you plan to set them out. Watermelons should only be planted when there is no danger of frost and the soil has warmed. In warmer climates, it is fine to start them outdoors as transplanting watermelons can be tricky. If you haven't timed your indoor seed starting just right, your plants may have grown too large to adjust to their new garden environment.
Mulch around watermelon plants in the garden to keep the soil full of nutrients and moisture. Mulch also prevent weeds, and in colder climates, it adds much-needed warmth to the soil around the melons as insulation. Mulch may be organic or a sheet of black plastic film.
Weed your melon garden with a shallow hoe, taking care not to dislodge any plant roots. Remove weeds with your hands (put on gardening gloves before to protect them if you wish) instead of the hoe so you don't accidentally damage a melon. Weeding is an important part of growing watermelons, it is really the only thing that you need to do for your watermelons daily. Your watermelon plants will not grow well if they have to compete with, or are shaded by weeds.
Provide adequate water, but don't overdo it. Watermelons will not set fruit if they do not get enough water, but will die if they get too much. Your plants are ready for more water when the top 1 to 2 inches of soil are dry.
Harvest watermelons when the curly tendril at the stem turns brown. The underside of the melon (where it's laying on the ground) will also start to turn yellow when it is ripe.