Description
Watermelon (Citrullus lanatus) is a flowering plant with a vine-like appearance native to Western Africa. Watermelon bears fruit that are widely cultivated and consumed across the world. Watermelon grow in tropical and temperate climates and requires warmth to grow. There are 1000 varieties around the world.
Watermelon is grown for its large edible fruit, which is a berry with a hard rind and no internal divisions, and is botanically called a pepo. The sweet, juicy flesh is usually deep red to pink, with many black seeds, although seedless varieties exist. The fruit can be eaten raw or pickled. It may also be consumed as a juice or an ingredient in mixed beverages.
Planting requirements
Planting season: Best planted during March to August
Planting conditions:
| Propagation | Direct seeding |
|---|---|
| Planting method | Plant seeds ¾ inch deep, shallower in moist soil. Sow 3-4 seeds per pit, 1.5 ft between pits, 3 ft between rows. Germination occurs in 10-14 days at 27-32°C. For gardens, use 3 ft² mounds 1 ft high, spacing seed groups 1 ft apart. Thin to 1-2 strongest plants post-germination. Allow 22 ft² per ground plant or use trellises in limited space |
| Soil | Well-draining, sandy or loamy soil rich in organic matter with a pH value from 5.5-7.0. Lateritic soils common in Sri Lanka are suitable when amended with organic matter. Prepare soil by weeding thoroughly, digging it over to loosen, and adding aged animal manure or compost |
| Water | Keep soil moist but never wet or dry. Water deeply in the early morning or late afternoon. Avoid watering the leaves to prevent fungal diseases |
| Light | Full sun. Choose a location that will receive at least 6 hours of full sun each day |
Growing conditions:
| Temperatures | Ideal daytime temperature is between 20-32°C (68-90°F). Nighttime temperatures should not drop below 16°C (60°F) |
|---|---|
| Soil | Keep soil moist and well-drained. Mulch after the seedling stage. In poor soil, use balanced or fruit/vegetable fertilizer. Apply high-nitrogen early, switch to high-potassium at flowering. Organic options like pelleted chicken manure are suitable |
| Water | Water regularly but reduce irrigation as fruits begin to ripen. Allow the top inch of soil to dry out between waterings. Ensure consistent moisture, especially during fruit development |
| Pruning | When vines are about 2 meters long, pinch out the tips to encourage branching. Remove side shoots and diseased leaves to maintain plant health. After several fruits have set on a branch, you can pinch out the tip of that branch to focus energy on fruit development |
| Weed control | Maintain weed-free conditions around plants. Use mulch to suppress weeds and avoid disturbing shallow roots when weeding |
| Pollination | Watermelons have separate male and female flowers on the same plant. If fruit isn't setting, you may need to hand-pollinate. Do this early in the morning by transferring pollen from male flowers to female flowers using a small brush or by removing the male flower and touching its center to the center of the female flower |
Harvesting
First harvest between 75 and 80 days of planting. Final harvest between 100 and 110 days of planting. Harvest watermelons when they are fully ripe. Signs of ripeness include:
- The underside turning from white to yellow
- The rind becoming tougher
- A dull thud sound when tapped
- The place where the fruit touches the ground turning yellow
- For the Thilini variety, the fruit starting to turn gray
Curing
Watermelon does not require a curing stage.
Storage
Store watermelons in a cool, dry place away from direct sunlight. They can be stored at room temperature for about 10-14 days or refrigerated for about 2-3 weeks. For best results, store watermelons between 50-60°F (10-15°C).
Protecting your plants
Pest control
Pest type:
- Leaf beetles
- Sap sucking insects
- Fruit spot
- Brown spot
Symptoms:
- Leaf beetles: Cause holes in leaves
- Sap sucking insects: Cause wilting and yellowing of leaves
- Fruit spot: Causes dark spots on the fruit rind
- Brown spot: Causes brown patches on leaves
Control method:
- Regular pruning of the plants is necessary
- Remove infected parts of the plant when spotted
- Use organic insecticides to ward off beetles and sap sucking insects
- Introduce natural predators like ladybugs to control pests
- Use neem oil spray as an organic pesticide option
Disease Control
Disease type:
- Anthracnose
- Fusarium wilt
- Powdery mildew
- Downy mildew
- Bacterial leaf blight
- Leaf spot virus
Symptoms:
- Anthracnose: Causes dark spots on leaves, stems, and fruit rind
- Fusarium wilt: Causes yellowing of lower leaves and wilting of plants
- Powdery mildew: Causes white patches on leaves
- Downy mildew: Can infect vines at fruiting time, especially in wet weather
- Bacterial leaf blight: Causes yellow-brown spots on leaves
- Leaf spot virus: Causes yellow spots and leaf deformation
Management:
- Maintain good air circulation around plants
- Avoid overhead watering to prevent fungal diseases
- Use fungicides as a last resort
- Apply a mixture of baking soda and water to control powdery mildew
- Rotate crops to prevent soil-borne diseases
- Remove and destroy diseased plants
- Use disease-resistant varieties when available
- Apply appropriate prescribed fungicides when necessary
Sources
In addition to our General List of Sources (link), we used these specific references:
