Citron melon, a rare melon for jam

Citron melon

Citron melon, or “jam melon“, is related to watermelon.

Key Citron melon facts

NameCitrullus lanatus var. citroides
Synonyms Citrullus caffer
FamilyCucurbitaceae

Type – vegetable/fruit vine
Planting distance – 3 feet/1 m apart
Exposure – full sun

Soil: rich, deep, well-drained   –   Bloom: summer   –   Harvest: late summer, fall

Keen growers know that citron melon is a valuable heirloom fruit. Indeed, the neutral taste helps make more delicate fruits go a longer way when making jams and jellies.

Growing and caring for citron melon

Citron melon grows as an annual vegetable or fruit in:

  • temperate climates with cold winters
  • hot climates with a rainy and a dry season.

In tropical climates or places with mild winters, the same plant may keep growing and fruiting throughout the seasons for several years.

Planting and sowing citron melon

Sowing from seeds is the most common way to grow it.

Make sure soil is very rich and deep.

Sprout seeds in spring indoors, transfer outdoors after the last frosts. Space plants by at least 3 feet, ideally 6 feet (1 to 2 meters). They grow very large!

Caring for citron melon

Plentiful water and lots of sun will lead to huge fruits. Pinching fruits so that only 3 remain will ensure each one grows very large.

Citron melon varieties

There are two groups of citron melons.

  • In Africa, North America, and a few other countries, the type of citron melon that grows is very close to citron melon in the wild. Fruits are round and tend to be a bit bitter when raw.
  • In Europe, however, citron melons have much larger and sweeter fruits. Selection by market gardeners over centuries resulted in more productive and appealing harvests.

Benefits of citron melon

Apart from the high pectin content ideal for jam, citron melon also has lycopene. Lycopene is an anti-oxidant.

  • Lycopene in the blood flow reduces incidence of chronic illness, as well as cardiovascular sickness and prostate cancer.
  • It functions as a hypocholesterolemiant, meaning it reduces cholesterol levels.
  • Also, it has anti-inflammatory properties.

What is citron melon?

Citron melon is an ancestor of today’s famous watermelon plant. It is a vine that crawls along the ground and up walls or fences.

  • Citron melon cookingFruits are similar to watermelon in size, sometimes larger. They’re either round like a basketball, or oval like a gigantic egg. Flesh inside is white or ivory-colored.
  • A mature citron melon weighs from 10 to 30 lbs (5 to 15 kgs)!
  • Flowers appear after the first half-dozen leaves. The yellow flowers are either male or female.
  • Only the female flowers bear fruits.
  • One or more stems travel from the root crown and spread to cover surfaces
  • Wide leaves soak up sun and smother other ground cover plants.
  • Roots reach deep into the ground and like rich soil

Let’s take a look at each part of the plant and get to know it better.

Cooking with citron melon

Citron melon jamIt has dense, white flesh that is a bit hard to cut. It feels a bit slimy to the touch.

  • Cutting citron melon is a bit dangerous. It’s similar to raw butternut or squash. Get a large cutting board and adequate knives.

Seeds are either green or red seed. They’re spread out throughout the flesh.

Even after harvesting, they still continue to ripen a bit. There’s no need to “leave them on the vine” once the vine has died out.

Citron melon can keep for months if in a cool, dry and well-ventilated pantry.

Citron melon flowers

It has solitary flowers with petals that are large and yellow which measures around an inch across (20-30 millimeters).

  • They grow on the stem, at the base of the leaves, but where along the stem is totally random.

Flowers are either male or female.

  • Female flowers are identified thanks to their pistils and ovary. The ovary is a swelling under the flower. It later turns into the fruit.
  • Only female flowers develop into fruits.
  • On the other hand, both male and females are crucial for  fertilization thanks to pollination. A female flower that isn’t fertilized won’t turn into fruit.

Citron melon pollinators

Pollinators are the usual in the garden:

  • many flies and small wasps love to pollinate this plant.
  • Apis mellifera, the honeybee, will also pollinate it.

In some settings there might not be enough pollinators. It’s always possible to hand pollinate citron melon.

  • Pick a male flower. Remove the petals carefully or fold them back.
  • Rub the remaining stamens that stick out of the middle onto the center part of the female flower – the pistils.

Stems and leaves of citrus melon plants

Stems will easily grow very long, up to a dozen feet (4 meters).

Leaves, though very wide, aren’t round. They’re like a large hand with frills around the fingers. They stand up at the end of a long stem (or petiole). All together, they form a bush that reaches knee height.

These crops will cover neighboring plants and climb up shrubs if there are any nearby. They use tendrils to lock on to twigs, branches, or anything they can use to climb.

  • Citron melon will smother any other low-lying crop if left unattended.
  • Unless it finds a way to climb, it will remain vulnerable to powdery mildew on hot days.

Citron melon root system

The root system of citron melon is incredibly dense.

  • A mature plant may have sent its roots to a depth of 4 feet (1.25 m).
  • Distance of the roots from the crown may reach 18 feet or 6 meters.
  • Each plant might send up to two dozen large roots in all directions.

Most of the roots are concentrated in the top 18 inches of soil though, or 45 cm.

Preparing soil to a depth of at least one foot is important.


Images: CC BY 4.0: Marius