Plant Answers  >  WATERMELONS

by Jerry Parsons, Ph.D.
Horticulture Specialist, Texas Agricultural Extension Service in San Antonio

A few days from now is the Fourth of July. If you don't have a fleshy canteen of sweet water cooling in the refrigerator, you will miss a real Independence Day treat. The flesh canteen which I am referring is a watermelon. The watermelon was the original portable flask, probably first originating in Africa. This was established by David Livingstone (noted missionary-explorer), in the 1850's. He found great tracts of watermelon (called kengwe or keme) growing wild in the Kalahari desert of Africa and the semi-tropical regions of Africa. Some evidence indicates possible American origins, as well. For example, early French explorers found Indians growing watermelons in the Mississippi valley.

Cultivation by man dates back at least 4000 years to the Egyptians, whose artistic records remain. Even today, in African semi-dry desert districts, watermelons are cultivated as an important source of water during dry periods. Old names in Arabic, Berber, Sanskrit, Spanish and Sardinian are all unrelated, indicating a great antiquity of culture in lands about the Mediterranean and east as far as India. It has no name in the ancient Greek and Latin languages, however, and thus was probably not known to these people much before the Christian era. It was probably introduced into Southern Europe by the Moors early in the Christian era. Albertus Magnus, 13th century, was among the earliest of the European botanists to describe the watermelon. It reached China, where it was called "si-kua", or melon-from-the-east, about the tenth century A.D., and eastern Russia before then. It was introduced into Britain in 1597. By the 16th century, watermelon was cultivated in Europe wherever it could be grown satisfactorily, and was described extensively by 16th and 17th century European botanists.

Watermelon was widely distributed throughout the remainder of the world by African slaves and European colonists. It was carried to Brazil and the West Indies, to eastern North America, to the islands of the Pacific, to New Zealand and Australia. Sturtevant reports the following written records of watermelon cultivation in the United States: in Massachusetts as early as 1629 (recorded by Master Graves, Massachusetts Historical Society); before 1664 being grown by the Florida Indians; in 1673 in the mid-west (reported by Father Marquette, who traveled the Wisconsin and Mississippi Rivers); in 1747, cultivated in Connecticut from seeds which came originally from Archangel in Russia; in 1799 being grown by the tribes along the Colorado River; and in 1822, in the Illinois region. Watermelons are now cultivated on all continents throughout the warm regions of the globe.

Watermelon is popular, especially in hot weather, for its sweet, cool, juiciness. Cooled and eaten in slices, it makes a quick, no-cooking, delicious dessert or snack, perfect for a picnic, or it can be served as part of a mixed fruit salad. An attractive party dish is made by cutting the melon in half lengthwise, scooping the fruit into balls, cleaning out the rind, and filling it with the watermelon balls, cantaloupe and honeydew balls, coconut and berries. The fruit can be juiced and used as a base for fruit punch, ices or molded jellies. The watermelon can be used as a party centerpiece and portable bar by cutting a plug in it and filling it with vodka, gin or rum. The juice is sipped out of the melon with straws. Watermelon pickles, made from the rind, are popular. Of course, some people try to "sweeten" the juice of watermelon with the desired liquor; it is less filling and makes one happier.

In other parts of the world, watermelon is eaten in different ways. In southern Russia, a beer is made from watermelon juice, or the juice may be boiled down to a heavy syrup like molasses for its sugar. In Iraq, and in Egypt and elsewhere in Africa, the flesh of the melon is used as a staple food and animal feed as well as a source of water in some dry districts. In the Old World, particularly Asia, the seeds are roasted, with or without salting, and eaten from the hand. Orientals also preserve watermelon by salting or bringing large pieces or halves in barrels.

Watermelon is much more nutritious than its name would imply. A wedge 4 X 8 inches .925 grams provides 2,510 International Units (IU) of vitamin A or about half the recommended dietary allowance (RDA). Such a piece also provides 30 mg. of vitamin C or two-thirds of the RDA. The iron in that amount of watermelon is 2.1 mg. or one-ninth of the 1974 RDA. At the same time, such a piece provides only 115 calories because watermelon is 93 percent water.

The composition of 100 grams of raw watermelon (edible portion), according to USDA handbook 8, is: "water, 92.6 percent, 26 calories; protein, 0.5 grams; fat, 0.2 g.; total carbohydrate, 6.4 g.; fiber, 0.3 g.; ash, 0.3 g.; calcium, 0.7 milligrams; phosphorus, 10 mg.; iron, 0.5 mg.; sodium, 1 mg.; potassium, 100 mg.; vitamin A, 590 IU; thiamine, 0.03 mg.; riboflavin, 0.03 mg.; niacin, 0.2 mg.; ascorbic acid, 7 mg.; magnesium, 8 mg."

Watermelon is often fed to people with kidney disease. Its juice is mild and, though it has no medicinal value, it is a juice which a kidney patient will accept.

How can you tell if a watermelon is ripe? Maturity is difficult to determine without plugging (cutting a small wedge) and testing. Usually, ripe melons of good quality are firm, symmetrical, fresh looking with an attractive waxy bloom, and with good characteristic color for the variety. The lower side should be somewhat yellowish where the melon contacted the soil. If a melon is very hard and is white or very pale green on the under side, it is probably immature. If so, don't undertake to ripen it: in the watermelon, total sugar does not increase after it comes off the vine. Thumping is used to check ripeness but the results will vary. Generally, a solid sound indicates ripeness while a sharp echoing sound indicates a greener fruit. Look for a typical melon the retailer has cut and then you can know what his melons look like inside. Melons should have good red flesh, that is crisp and not mealy or water soaked (from bruising). Seeds, which can vary in color from white to black depending on the variety, should be fully mature and hard. At home, watermelons may be kept at room temperature until cut or may be refrigerated.

Regardless of how you eat it, watermelon will make your Fourth of July a memorable one.


How can you tell if a watermelon is ripe? Maturity is difficult to determine without plugging (cutting a small wedge) and testing. It is VERY important not to harvest melons when they are immature because total sugar does not increase after they come off the vine. Four commonly used methods (harvest indices) for determining watermelon maturity are: METHOD CHARACTERISTIC CHANGE IN FRUIT

1. Color of: Color of rind on the part of the "ground spot" melon touching the ground ("ground spot") changed from greenish-white to pale yellow when ripe.

2. Sound when thumped: Ripe melon emits a dull or hollow sound, compared to a clear ring of an immature fruit.

3. Condition of tendril: Tendril at the point of adjacent to stem end. attachment withers and dried out at fruit maturity.

4. Feel and appearance of: Rind feels slightly rough with rind surface dull, opaque appearance, compared to the shiny, glossy, smoother feel of an immature fruit.

In general, no one method will guarantee identification of the desired stage of fruit maturity during the critical 10-14 day period in which a typical red-fleshed watermelon passes from immature pink to red ripe to over-ripe. Indeed, these four methods are only indicators of fruit ripeness and the exact stage of maturity can only be determined by "plugging" or sampling a section of the fruit for flavor and soluble solids. Obviously, "plugging" is a destructive process and can only be used to determine the maturity of a representative sample of a grower's field on a given date. Plugging to verify the accuracy of the four non-destructive methods outlined above is highly recommended, especially for someone who is not highly experienced in assessing watermelon maturity.

Relative fruit size is another non-destructive harvest index for estimating watermelon maturity. However, extreme caution must be exercised when using fruit size alone as a harvest index. While fruit size is characteristic for each variety at maturity fruit size can vary considerably because of difference in (a) fertility and moisture conditions of the soil, (b) plant spacing and density, and © time of year. In general, the first fruit set are the largest and fruit size becomes smaller as the season progresses. Soil productivity may even vary considerably within the same field resulting in a distinct variance in the size of mature fruit in different sections of the field the same day. The degree of reliability or effectiveness of nondestructive harvest indicates may vary among varieties. Thus, the grower or home gardener will need to adopt a strategy for harvesting each variety based on wise use of plugging to determine actual fruit quality correlated with the four nondestructive harvest indices.

Of course if you buy the Fourth of July treat in the supermarket or produce stand, the watermelon will have been harvested at the peak of maturity and will be ready to "soothe your savage thirst".


Copyright © 2024 - All Rights Reserved. PLANTanswers and are trademarks of Jerry Parsons.