The life of a watermelon plant starts with a seed. The seed is a flattened ovoid that is usually dark brown and hard. Watermelon seeds range from 1/4 to 1/2 inch long. The seeds are planted in soil about 1 to 1 1/2 inches deep and need to be watered regularly.
Germination and Plant Growth
The seed will then germinate and send out a root growth and two seed leaves called cotyledons. As the seedling continues to grow, runners will be sent out along the ground and more leaves will form along each vine. The root system will branch loosely and grow to about 2 meters deep.
The vine will grow continuously during the life of the plant, reaching a length of several feet. The leaves will sprout along the vine 3 to 5 inches apart. The leaves are dark green and have prominent veining. They have three lobes that differentiate into smaller lobes. Both vines and leaves are covered with hairs. Tendrils will also be sent out to anchor the plant.
The watermelon plant will eventually produce singular, five-petaled yellow flowers about an inch across that sprout near the leaf stems. Watermelon plants produce both male flowers that produce pollen and female flowers that--once pollinated--will produce fruit. The flowers will open before sunrise.
Watermelons are not self-fertile and require pollination, which is generally accomplished by insects. Pollinators are primarily different species of bees. Honey bees are used commercially to pollinate watermelon crops.
Once pollinated, the female flower will begin to form an immature watermelon. As the watermelon grows, the flower portion will eventually fall off. Each melon is green with stripes down the length of the fruit. The melon will continue to grow until ripe. The side of the watermelon on the ground will sometimes turn yellow. Watermelons can range in weight from 5 to 50 pounds, depending on the variety.
Seeds form within the melon, surrounded by sweet, red, juicy flesh. Seeds within some types of watermelon fail to mature completely and are edible. These watermelons are often labeled as "seedless." The fruit is ready to pick when the stem it is attached to is dry and brittle.