This frost-sensitive annual vine has been in cultivation since 2000 B.C. or so.
The plant size depends upon the variety being grown. These vines feature branched tendrils. Usually hairy, the alternate, broad leaves can have three to five lobes, which are also lobed.
The light yellow blossoms open singly in the leaf axils with the males and females being separate on the same plant.
The large, oblong to round fruits are berry-like. Up to ten inches across, these have a hard rind that can vary in color from green to blackish-green. Often, this is marbled or mottled.
The flesh can be white, pink, red, or yellow. It tastes sweet but watery. Under good growing conditions, the fruits can weigh fifty to a hundred pounds.

Pollinator Value of Watermelons and Pollination
These flowers are sources of pollen and nectar. Pollinators are very fond of watermelon blossoms. When watermelons are grown commercially, this can result in a crop of honey. The good quality, pleasant tasting honey is amber.
In order to bear fruits, watermelon blossoms require pollination in order to produce fruits. Proper pollination affects not only the number of fruits set but also the shape and size of the fruits.
A watermelon blossom is open only for a single day and closes in the afternoon. These emerge from one to two hours after sunrise with most pollination occurring before the afternoon arrives.
A flower requires as many as eight visits by a pollinator for proper pollination. Pollen recommendations vary according to the source, anywhere from one to five bee hives per acre or one colony per acre or two acres.

Generally, watermelons require a longer growing season than most other melons. The early varieties ripen in about a hundred days, while the later varieties take 1
20 days or so.
For short season areas, use early maturing varieties and start the seeds indoors about three weeks or so before the last expected frost date.

Select a spot in full sun. Plant the transplants or seeds after the last frost when the weather is warm and settled. If necessary, cover the soil with black plastic mulch or landscape fabric several weeks before planting to heat up the soil.

The ideal soil temperature for planting watermelons is 70 to 85 degrees F. Cold soils inhibit seed germination.

If using plastic or fabric mulch, cut holes in this at planting time to insert the seeds or plants. Plant the seeds ½ inch to an inch deep, according to the soil type.

Germination occurs in five to ten days. After planting, use row covers or Hot Kaps if necessary to keep the plants/seeds warm.

Watermelons are grown pretty much like other melons with just a few differences. Prepare the soil before planting, and add compost, rotted manure, or similar amendments into the soil.

These melons do best in a sandy loam or rich, organic well drained soil with a pH of 5 to 7. Avoid spots in the garden where you’ve previously grown cucumbers, watermelons, or other melons within the last two years.

The spacing varies according to the variety being grown. They can be planted in rows or in hills.

Watermelons are different than most vegetables by requiring additional fertilizer during the growing season. A balanced general purpose formula, such as a 10-10-10, works fine. Mix the first application into the soil before planting.

Then, apply on a regular basis about every four to six weeks throughout the growing season until the plants set fruits. Fish emulsion is a suitable alternative to chemical fertilizers.

Weeding is more of a concern for younger watermelon plants as larger ones can outgrow the weeds.

Many varieties of watermelons are available. The bush types save space. Seedless varieties of watermelons can occasionally produce seeds if the plants become stressed.

Watermelons experience the same problems seen in cucumbers and other melons. Some diseases can be prevented by using resistant varieties and controlling cucumber beetles and aphids.