Introduction to watermelon cultivation
Watermelon (Citrullus lanatus) is one of the most prized fruits for its refreshing flavor and high water content. Belonging to the Cucurbitaceae family, like melon or zucchini, it is characterized by its large size and thick, green skin, which protects its sweet and juicy flesh. This crop, native to warm regions, has spread throughout the world due to its ease of cultivation and the abundance of fruit it can produce.
Optimal conditions for growing watermelon
To obtain quality watermelons, it is essential to provide a suitable environment. The three keys to success are sun, water and enough space.Watermelon needs full sunlight (at least 8 hours a day), well-drained soil rich in organic matter, and ample space to develop its long vines.
Light needs
The precise watermelon lots of direct lightA minimum of eight hours of light per day ensures the development of large, sweet fruits. The quantity and quality of light during flowering favors pollination and fruit growth.
In excessively hot climates, it can tolerate some light shade during the hottest hours, but it should never be grown in shady locations, as this affects sugar production and fruit size.
Temperature and humidity
Watermelon thrives in warm climates and requires constant temperatures between 21 and 29°C during the day, tolerating slightly higher peak temperatures. Frost is fatal for this plant, so it's best to wait until there's no danger of low temperatures before planting or transplanting.
The soil must maintain adequate moisture, especially during flowering and fruit set. However, Good drainage is more important than keeping the soil constantly moistExcessive humidity increases the risk of fungal diseases.
The best soil for watermelon
Watermelon demands light, sandy-loam soils, well aerated and rich in nutrientsIt is advisable to till the soil deeply (about 30-40 cm) and enrich it with mature compost or manure to ensure good root development and avoid waterlogging.
The optimal pH is between 6,0 and 6,8. If the soil is excessively acidic or basic, it is advisable to amend it. A properly balanced soil in terms of nutrients and pH promotes greater resistance to pests and diseases.
Land preparation and planting
Soil cleaning and structure
Before sowing, it is essential to clear the soil of stones, plant debris, and weeds. The soil should be tilled thoroughly to break up clods and promote aeration. Adding organic matter (compost, well-rotted manure) helps improve soil structure and fertility.
When and how to plant watermelon
Sowing should be done when the soil temperature reaches at least 18ºC, a few days after the risk of frost has passed. In warm regions, it's possible to sow directly outdoors; in cold climates, it's best to start sowing in a seedbed or protected under a tunnel in late winter and transplant when temperatures rise.
- Direct sowing: Dig holes 3-4 cm deep, place 2-3 seeds per hole, and cover gently. When the plants have 2-3 true leaves, thin out and leave the most vigorous one.
- Sowing in seedbed: Sow in trays and transplant outdoors when the seedlings have 3-4 leaves and temperatures are suitable.
Planting frame: Leave a minimum distance of 1,5-2,5 meters between plants and between rows, depending on the variety. Watermelons need space to develop fully.
Essential care after planting
Efficient irrigation
Irrigation is one of the key aspects. Immediately after planting or transplanting, water thoroughly to establish the plant. After this stage, watering should be light but frequent until the beginning of fruit formation.
- During flowering and fruit set, maintain constant humidity.
- As the fruit ripens, space out watering to improve sweetness and prevent the fruit from cracking.
It's advisable to avoid wetting the foliage to prevent fungal diseases. The most effective method is drip irrigation, which moistens the root zone directly without flooding the soil.
Fertilization
For vigorous development and good production, watermelon needs nutrients in sufficient quantity:
- Nitrogen (N): stimulates initial vegetative growth.
- Phosphorus (P): essential for flowering and root development.
- Potassium (K): key to the formation and ripening of fruits.
- Calcium, magnesium and sulfur: also essential, along with micronutrients such as iron, zinc or boron.
If you opt for the organic watermelon farmingIt is recommended to apply mature compost, worm castings, or natural fertilizers. In conventional agriculture, dividing the fertilizer dose helps prevent losses and maximize absorption.
Pruning and guiding the plant
Watermelon is a trailing plant with very vigorous growth. To make the most of the space and promote large fruits, it is advisable prune the side branches, guiding the plant through arches, tutors or simply delimiting the space on the ground.
Pruning should be moderate and focused on removing damaged parts and controlling excessive branch development, which helps the plant concentrate its energy on the fruit it forms.
Control of pests and diseases
Among the most common pests include:
- Aphid
- Red spider
- Caterpillars
As for the enfermedadesFungi such as powdery mildew and Fusarium are the most problematic. To prevent this, it's essential to keep the soil well-drained, avoid excess moisture, and rotate crops each season.
Frequent monitoring and manual pest removal or the timely use of organic treatments, such as potassium soap or garlic extracts, can help maintain crop health.
Growth and maturation cycle
El watermelon growth period It depends on the variety and environmental conditions, but typically ranges from 70 to 100 days from planting to harvest. Small-fruited varieties tend to ripen earlier, while larger varieties require a longer cycle.
During this time, temperature monitoring and proper water and nutrient management are essential for achieving abundant harvests and excellent-tasting fruits.
How and when to harvest watermelons
One of the challenges in watermelon cultivation is getting the harvesting time right, as premature harvesting results in tasteless fruit, and delayed harvesting can cause the flesh to lose texture.
- The tendril closest to the fruit dries up and turns brown.
- The stain on the ground turns a deep yellow.
- The bark goes from shiny to matte and becomes difficult to scratch with a fingernail.
- If you tap it lightly, it makes a hollow sound.
To harvest the watermelon, use a sharp knife, leaving part of the stem attached to the fruit. It's best to harvest on a dry day to avoid moisture damage.
Storing and preserving watermelon
After harvesting, watermelons should be protected from strong sunlight and stored in cool, well-ventilated areas. The ideal temperature is between 10 and 16°C. They should not be refrigerated below 10°C because they can suffer chilling damage, which affects the color and texture of the flesh.
Placing fruit on straw or hay helps prevent bruising and prolongs its shelf life. Properly managed watermelons can remain in perfect condition for several weeks after harvest.
Obtaining and preserving seeds
If you want to extract seeds for future harvests, select watermelons that have fully ripened on the plant, preferably near the root. Once the seeds have been extracted, they are washed and dried completely in the shade before being stored in airtight jars in a dry, dark place.
Saving seeds from hybrid varieties is not recommended, as the offspring may not retain the desired characteristics.
Main varieties of watermelon
- Crimson Sweet: with red pulp and intense flavor.
- Sugar Baby: small, ideal for urban gardens.
- Yellow Crimson: yellow and very sweet pulp.
- Black Diamond: very dark bark and large fruits.
Each variety has different space and cycle needs, but in general they all require similar care.
Frequently Asked Questions About Growing Watermelon
- How do you fertilize watermelon?
It's recommended to fertilize before planting with compost or a balanced fertilizer. During growth, provide nutrients rich in nitrogen, phosphorus, and potassium, dividing applications according to the development stage. - How far apart are watermelons planted?
It depends on the variety, but it is common to leave between 1,5 and 2,5 meters between plants and 1,8-2,4 meters between rows, to ensure sufficient space between the guides. - Striped or smooth watermelon, which is better?
Both vary more in flavor and texture depending on ripeness and growing conditions than in skin color. Many people prefer striped ones for their sweetness, but it's a matter of preference.
Integrating it into your garden allows you to obtain tasty, refreshing, and highly nutritious fruits. By applying the care described here and choosing the right planting and harvesting time, you can enjoy excellent quality watermelons even in small spaces. The key is to monitor the plant, adapt watering and fertilization to its needs, and prevent pests and diseases in an ecologically sound manner whenever possible.