Watermelons are popular garden plants commonly grown for the large, sweet fruit they produce. A watermelon takes between 70 and 85 days to grow from seed to maturity, depending on the variety. The fruit produced ranges between 6 and 26 pounds depending on the cultivar and time of harvest. Watermelons are easy to grow from seed and require only basic care to thrive and bear fruit.
Plant watermelon seed during spring once all danger of frost has passed in a location that receives full sunlight. Spread 3 inches of organic manure over the planting site and use a garden tiller to incorporate it into the soil to increase drainage and fertility.
Fertilize the soil at the site prior to planting to further increase the nutrients available to the plant. Use a low-potassium 16-16-8 NPK fertilizer to provide the proper nutrients for vigorous growth and fruit formation. Apply following the manufacturer's directions for proper dosage.
Form small hills in the soil about 6 feet apart. Sow up to five watermelon seeds 1 inch deep in each hill. Water lightly after sowing to bring moisture into contact with the seeds and initiate growth.
Water the watermelon seed once per week until the seedlings emerge and reach 3 to 5 inches in height. Thin the seedlings by removing the weakest three plants and leaving the two strongest in place. Reduce the frequency of watering thereafter to once every 10 days.
Use a hoe to gently uproot any weeds that form without damaging the root system of the watermelons. Spread a 2-inch layer of mulch over the soil surrounding watermelons to further suppress weeds and increase moisture retention of the soil.