For me, watermelons are one of the most amazing crops to grow. From skinny vines and small, pale yellow flowers there appears a fruit whose succulence and sweetness punctuates the summer experience. Throughout our country, we tend to have different experiences when it comes to watermelon growing and eating.
Watermelon loves heat and lots of it. In most of the cooler parts of the country, for example the Northeast, the large, oblong and weighty melons will not mature. The rounder shorter-season varieties of watermelon, sometimes dubbed icebox watermelons, will usually do well depending on the weather, latitude and elevation. A slightly cooler summer or a rise in elevation may not allow melons to fully ripen in some locations. In northern coastal or mountain areas, watermelon cultivation outside of a greenhouse may be impossible.
Heirloom watermelons of comparable size typically ripen later than hybrids. For growers in cooler climes, heirlooms are riskier. In the case of northern regions, there are a number of modern varieties that will mature a couple of weeks earlier, such as Golden Midget, Sugar Baby and Blacktail Mountain.
Watermelon, Citrullus lanatus, is a frost-sensitive annual vine with deeply indented, lobed and hairy leaves with climbing tendrils. It is a member of the squash family, and it has a superficial resemblance to squash plants. The vines produce unisexual flowers — that is, either male or female flowers as opposed to bisexual or perfect flowers like a lily or rose. Its fruit is a large berry called a pepo.
The genus Citrullus comprises four species, including watermelon and Citrullus colocynthis, a perennial known as bitter gourd or apple, which occurs as both a wild and domesticated plant. It was used as a purgative and antiparasitic — among other uses — since ancient times and is mentioned in the Bible.
Two other species of Citrullus are endemic to the Namib Desert of southwestern Africa, C. ecirrhosus and Citrullus rehmii.
All species of Citrullus are derived from wild C. lanatus, which originated in the subtropical regions of southern Africa particularly in the Kalahari Desert. Here, a small melon grows wild known as tsamma or tsama, believed to be the ancestor of our modern-day watermelon. These melons form a “group” of closely related variants, though they differ widely in taste and uses by indigenous people. Many are bitter and roasted over a fire before consumption, while others are somewhat sweet and eaten fresh. Some types appear to be more closely related to the citron melon, C. lanatus var. citroides, a small domesticated heirloom variety whose rind is used in pickling and preserving. The tsamma melon was used as a source of water for people crossing the desert, and the story goes that it was only possible to cross during tsamma season. The bitter C. ecirrhosus also is referred to as tsamma.
Watermelon fruit tends be round, oval, somewhat or distinctly oblong with light to dark green background with darker stripes or mottling, or large and small yellow “spots” in the case of the Moon and Stars watermelon. Flesh color varies from red to pink, yellow and white.
A small number of heirloom watermelon varieties are common, but a rich offering of long- maintained and rediscovered heritage varieties can be found, if one searches diligently.
Perhaps the most famous watermelon of the heirloom seed movement is the aforementioned Moon and Stars watermelon. Kent Whealy, co-founder of the Seed Savers Exchange, had been on the lookout for a variety that had been introduced as Sun, Moon and Stars by the Henderson Seed Co. in New York in 1926, which he believed to be extinct.
In 1982, Whealy mentioned this variety on a radio show in Missouri and soon received a phone call from a listener, Merle Van Doren, a farmer who still maintained the variety. Since then, several variants have surfaced, including the sweet, ruby-fleshed Cherokee Moon and Stars and a more subtly flavored yellow-fleshed version.
Moon and Stars are oval to oblong in shape, dark green, generally with slight to pronounced ribbing. The distinct, seemingly random pattern that gives these melons their name is composed of small yellow dots and speckles of varying size (stars), with one or more larger round yellow patches (the moon). The leaves also are mottled with bright yellow spots. The rind is thick and the delicious, moderately sweet flesh varies in color from yellow to pinkish to brilliant red.
Fruits commonly grow from 15 to 25 pounds, though a few companies claim they can reach 40 pounds under the right conditions. Moon and Stars is a fairly long-season variety that takes from 90 to 100 days to mature. Seeds are brown with black speckles, and like all heirloom watermelon varieties, the fruits are relatively seedy.
Georgia Rattlesnake is an heirloom variety that dates back to at least 1870, although it probably was developed earlier in Georgia.
It’s one of the archetypal oblong watermelons, 2 feet in length and weighing 25 to 30 pounds and sometimes as much as 40. It derives its name from the dark green, snakeskin-striped pattern running its length over a light green background.
The flesh is bright scarlet-pink and quite sweet. The rind is tough, though not thick, making it an excellent shipper. These characteristics combined with its shape, which allows for stacking, made it a favorite for both home and market growers. It requires about 90 to 100 hot days to ripen.
Another great long-season melon was developed by an Alabama watermelon grower, W.A. Kleckley, in 1887, and it was introduced as the KleckleySweet by Burpee in 1897. It also was introduced by Robert Buist Co. as the Monte Cristo, although it is debated whether that occurred before or after Burpee’s introduction.
As the story goes, Kleckley developed the melon by crossing Boss and Arkansas Traveler. Like Rattlesnake, it grows from 25 to 40 pounds and needs about 85 days to mature. It is considered an earlier-maturing variety than some of the other large melons, although it takes longer as you move north — figure 100 days in most places. The rind is dark blue-green, and the flesh is dark red and very sweet.
If you want to taste this excellent variety, you’ll probably have to grow it yourself — the skin is thin and relatively brittle, consequently it’s not grown for shipping.
One of my personal favorites is Cream of Saskatchewan. It has white flesh with an excellent sweetness and an underlying creamy flavor. These melons were supposedly brought to Canada by Russian immigrants. Large, white melons were known to have been popularly cultivated in warmer parts of Russia in the early 19th century.
Cream of Saskatchewan is fairly round and relatively small, 5 to 10 pounds in size, with dark green stripes over a lighter green foreground. It ripens early and is perfectly suited to cooler climates.
I call this the “exploding” watermelon because sometimes, when they are perfectly ripe, a small tap on the outside will result in the melon cracking and popping open. This results in the melons occasionally splitting open on their own in the field. If this happens, brush off the ants and eat the melons fairly promptly, or refrigerate. Because this easy-splitting characteristic precludes commercial production, the only way you are going to enjoy them is to grow them yourself.
The interior is filled with dark brown seeds, which some people who are wedded to the modern concept of seedless watermelon may find difficult to stomach. After all, are we going to lose the tradition of eating watermelon outside on a warm summer evening and spitting the seeds, all because of the “tidiness” of seedless watermelons?!
So while it may be a bit early in the year to plan for next year’s watermelon harvest, start looking for some of the wonderful taste sensations available in heirloom melons. And one of the great characteristics of watermelon is that they keep perfectly well at room temperature for weeks, with the thicker rind varieties keeping for months. Watermelon at Christmas is even a tradition for some families!
Ethnobotanist and former director of the Eastern Native Seed Conservancy, Lawrence Davis-Hollander gardens, cooks, and — at a nearby preserve — watches bald eagles and seasonal wildflowers.
Eat the watermelon seeds
The seeds are the most nutritious part of the fruit, and they are quite edible. Watermelons contain good amounts of vitamins A and C. The seeds contain high amounts of protein and fat. In China, many varieties are bred specifically for their watermelon-seed production. The most nutritious cultivars are from southern Africa where one of the varieties known as Egusi is cultivated specifically for its seeds, which are roasted and eaten or ground into seed butter.