Plant
Watermelon is a creeper with herbaceous stem and tendrils. The roots are shallow (40-50 cm) and (60-90 cm) widespread. The weeping stem is hairy and either round or angular in shape. The tendril, leaf and flowers arise from one point on the stem.

Leaves
The leaves of watermelon are oval in shape, deeply lobed and about 10-20 cm long.

Flowers
The flowers of watermelon are monoecius , i.e. the same plant contains both male and female flowers. Each flower is about 1.5-2.0 cm wide and is sulphur yellow in colour. At times, hermaphrodite flowers can occur. The flower comes in between the leaves and is pollinated by insects.

Fruit
The melon fruit is either round or oblong in shape. It has a smooth skin. The standard watermelon weighs between 7 and 15 kg. Newly developed varieties from Taiwan are small in size (4 to 6 kg/fruit). The colour varies from light green to dark green with stripes. The flesh can be white, cream yellow, pale red, red or dark red in colour. The seed is small and located within the flesh. The length is about 5-15 cm long. It could be white, black, brown, yellowish and pink in colour.

The length of the total growing period ranges from 80 to 110 days, depending on climate. The growing period is shorter in tropical climates, 70 – 95 days, depending on the varieties.

Harvesting generally begins 30 days after full bloom and can continue for several weeks.

Watermelon performs well in a hot, dry climate with mean daily temperatures of 22 to 30°C and an abundance of sunshine. Maximum and minimum temperatures for growth are about 35 and 18°C respectively. The optimum soil temperature for root growth is in the range of 20 to 35°C. Fruits grown under hot, dry conditions have a high sugar content of 11% in comparison to 8% under cool, humid conditions. The optimum monthly rainfall is 250mm or less. Most well-drained soil, whether clayey or sandy, can be managed to produce a good crop of watermelon. The best soils, however, are sandy loams that are not prone to water-logging, with a pH of 5.8 to 7.2

People have loved watermelon throughout the world for centuries. The Egyptians grew watermelons more than 5,000 years ago, decorating wall paintings with watermelon. From Egypt, watermelon's popularity grew as traders began selling seeds along Mediterranean trade routes. By the 10th century, watermelon made its way into China and by the 13th century, the Moors introduced watermelon into southern Europe. Modern varieties of the watermelon are derived from the native African vine Citrullus lanatus. Cultivated for thousands of years in the Nile Valley, this species still grows wild in the arid interior where it supplies native people with water during drought seasons. Wild watermelons, called citron in Africa, have a spherical, striped fruit, and white, slightly bitter or bland flesh. The pale flesh tastes like the rind of a typical watermelon. The citron is also called "preserving melon" because the fruit rind is used in preserves, jellies and to make pickles or conserves. Because of its high pectin content, it is added to fruit juices to make them jell more rapidly. One plant may produce up to 100 fruits, which are commonly fed to livestock.