Watermelon (Citrullus lanatus) is one of the most emblematic fruits of summer. Thanks to its high water content and refreshing properties, it becomes the preferred choice for both family and commercial consumption. However, to enjoy a watermelon at its optimal point—sweet, juicy, and of the highest quality—it is essential to know the exact time of harvest and master the proper techniques for harvesting and preserving it. Throughout this extensive article, you'll learn all the secrets and methods that professionals and experienced farmers use to achieve perfect watermelons, from cultivation to final storage.
How many harvests does a watermelon plant produce?
When discussing the yield of a watermelon plant, it's important to differentiate between home cultivation and commercial production. When growing watermelon at home, you can pay much closer attention to each plant, optimizing the number and quality of fruit you receive. However, in large-scale cultivation, volume is a priority, and such detailed monitoring isn't always possible, which can affect the size and quality of the watermelons obtained.
On average, a healthy watermelon plant can yield between 2 to 6 fruits per seasonAlthough under ideal conditions and with advanced management techniques, some growers manage to exceed this number. However, it's important to consider that excessive fruit production on a single plant can reduce quality: the fruit can become small and less sweet if the plant's energy is spread too thin. Therefore, selective pruning and proper resource management are essential.
Most watermelon varieties produce a single crop per growing season. Once the plant has produced its main fruits and these have been harvested, the plant usually tends to dry out or lose vigor. However, in controlled environments, in pots, or with special care, the plant may remain active and produce a few more fruits, although this is not common in open-field crops.
When does watermelon bloom?
The flowering of the watermelon represents the beginning of the process that will culminate in the formation of the fruit. It usually begins in the warm weather months, usually from May or June depending on the region and the cultivated variety. To promote flowering and subsequent fruit setting, it is essential that the plant receives plenty of sunlight and that the ambient temperature is between 21 ° C and 29 ° C. Lower or excessively high temperatures can negatively affect pollination and fruit development.
On the other hand, during the flowering stage it is essential increase irrigation, since the plant requires greater amounts of water to feed the accelerated growth of its flowers and fruits. Poor irrigation at this stage can result in fewer fruits or in fruits that are smaller and sweeter.
Not all watermelon varieties bloom at the same time, and some may bloom earlier or later depending on environmental conditions and planting date.
How is watermelon grown?
Growing watermelon is relatively simple, but to obtain quality watermelons it is essential to pay attention to several key factors: sowing method, the substrate type, the management of the irrigation, the temperature, the pruning and the Control of pests and diseasesLet's look at each aspect in detail so you can achieve maximum performance and the best quality from your fruits.
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Watermelon offers different cultivation methods, each with specific advantages and characteristics:
- Sowing by seeds: It takes between 100 and 120 days to reach harvest. The substrate temperature must be maintained around 18ºC At the very least, seeds germinate poorly in cold soils. It's crucial to ensure that the seeds are of good quality and to plant only those with a high germination rate (85-90%). Sowing can be done directly into the ground once the risk of frost has passed and the soil has warmed up sufficiently.
- Sowing by non-grafted seedlings: It allows for a certain amount of anticipation of the harvest and a more precise selection of the variety according to the type of soil and the climate of the area.
- Sowing by grafted seedlings: It is the most common option in commercial crops and allows to speed up the process, since the plants can be ready to harvest in 75-90 days since the transplant.
To successfully plant watermelon:
- Clear the area of ​​stones, plant debris and other obstacles.
- Deep tillage (30-38 cm) to aerate and decompact the soil.
- Amend the soil with compost, well-rotted manure, and, if necessary, lime to adjust the acidity.
- Maintain adequate humidity, but avoid waterlogging.
- Use soil solarization by covering it with black plastic if you're looking to get a jump start on the season.
Sowing can be done indoors (2-3 weeks before the last frost) in cold areas, or by direct sowing in the field in warm regions.
Substrate and optimal conditions for cultivation
Watermelon needs soil Rich in nutrients, loose and with very good drainageThe ideal soil type is sandy loam, although it can adapt to almost any soil as long as it does not become waterlogged, which causes rot and disease. The optimal soil pH ranges from 5,8 and 6,6, an acid value that improves nutrient availability.
If growing in a pot, use a mixture of fertile soil, compost, and material to improve drainage. If growing outdoors, prepare the soil well in advance to ensure it's well-aerated. This includes:
- Oxygenate the soil five months before transplanting or direct sowing.
- Remove stones, roots and debris from previous crops.
- Add organic or chemical fertilizers according to the needs detected in a soil analysis.
- Keep the soil loose to facilitate the development of deep roots.
Controlling the temperature is essential. Watermelon needs less than 18ºC For proper germination, and during vegetative development and flowering, the ideal temperature is 21°C to 29°C, occasionally tolerating temperatures as low as 32°C. Below 10°C, the plant suffers, and the risk of frost is fatal, so it should never be planted before this danger has passed.
Watermelon watering
Irrigation is one of the key factors throughout the entire growing season, but it becomes especially important from the moment flowers appear and during fruit development. Watermelon requires constant moisture, but is sensitive to waterlogging. Excess water can promote fungal growth and cause root and fruit rot.
The recommended thing is:
- Use drip irrigation, ensuring uniform humidity and avoiding wetting the leaves.
- Water early in the morning in the early stages and late in the evening in more advanced stages.
- In dry climates, adjust daily watering, while in humid areas, rainwater and monitoring soil moisture may be sufficient.
- A need is estimated for 400-600 mm of water per season, although this data may vary depending on the soil and climate.
Check soil moisture before watering and reduce the frequency if heavy rains are expected. During heat waves, increase the frequency to avoid water stress that could affect fruit development.
Fertilization and manure
Watermelons are plants with high nutritional requirementsThey need balanced fertilization in nitrogen, phosphorus and potassium, respecting the global dose that for commercial crops is usually around 134 kg / ha among the three main nutrients. It is advisable:
- Provide all the phosphorus and potassium before sowing or transplanting.
- Divide the nitrogen dose in two: half before planting and the other half between the fourth and sixth week after transplanting.
- Use slow-release, organic fertilizers such as compost or guano to maintain soil fertility and prevent overburning.
Additionally, if you want to fine-tune fertilizer application, you can use multi-zone maps and monitoring systems like those used by professional farmers to identify areas with deficiencies or excesses and respond accordingly.
watermelon pruning
La pruning is not mandatory in home watermelon cultivation, but it can help improve fruit quality. Removing secondary shoots and poorly formed or very small fruit allows the plant to concentrate its resources on the largest and healthiest watermelons. Pruning should be done at the initial development stage, disinfecting tools to prevent infections. Some growers also cut off dry or diseased leaves to facilitate aeration and reduce the risk of pests.
Control of pests and diseases
Watermelon is relatively hardy, but can be affected by various pests and diseases:
- Pests: Among the most common are thrips, aphids, mites such as tetranychus urticae and the cucumber beetle. These pests typically attack leaves and stems, stealing sap and transmitting viruses.
- Diseases: Anthracnose, powdery mildew, and downy mildew are the most common diseases. Anthracnose causes spots on the leaves and veins, while downy mildew causes yellow or gray spots, and powdery mildew forms a whitish mold that dries the leaves. All cause general weakening of the plant and reduced yield.
The key is in the early detection and integrated management, using certified organic products, eliminating residues from previous harvests and promoting ventilation between plants.
When is watermelon harvested?
El right time to harvest watermelon It is essential to enjoy all its flavor and crunchy texture. Generally, the watermelon will be ready to be picked between 70 and 100 days after sowing or transplanting, depending on the variety and growing conditions. Smaller varieties tend to be ready sooner, and some commercial varieties can mature after 95 days.
To identify whether a watermelon is ripe and ready to be harvested, look for these key signs, confirmed by expert farmers and disseminated by organizations such as the FAO and the National Watermelon Promotion Board:
- Color change in the basal spot: The part of the watermelon resting on the ground changes from white or light green to a creamy or deep yellow. This is one of the most reliable visual clues.
- Presence of waxy dust: The rind of ripe watermelon often has a thin, whitish, waxy coating that gives it a less shiny appearance.
- Dry peduncle or stem: The tendril, or part of the stem that connects the watermelon to the plant, should be completely dry and brown before cutting into the fruit. A green stem indicates that it has not yet fully ripened.
- Hollow noise when hitting: When you lightly tap a ripe watermelon, you should hear a deep, thud, indicating that the flesh is well hydrated and ripe.
- Opaque and hard bark: The surface of mature bark loses its intense shine and becomes more dull. Furthermore, the bark becomes difficult to scrape off with a fingernail.
- The end of the fruit is somewhat soft: The end opposite the stem softens slightly when the watermelon has fully ripened.
Of all the signs, the combination of a dry tendril, a yellow spot at the base, and a hollow sound are the three most universal parameters used by both traditional farmers and young experts who share their methods on social media.
How to harvest watermelon correctly?
Once you've identified the optimal ripeness, it's time to harvest the watermelon. The process is simple, but there are details that make the difference in keeping the fruit in perfect condition and avoiding subsequent damage or disease.
- Use sharp and disinfected tools: Use a serrated knife, pruning shears, or sharp knife that has been cleaned and disinfected (you can use water with a few drops of detergent, rinsing well).
- Cut the stem leaving a small piece attached: Experts recommend leaving between 2 and 5 centimeters of stem attached to the fruit. This helps retain moisture and prolongs freshness, while also reducing the risk of disease.
- Avoid throwing or dragging the watermelon: Hold it by both ends to avoid damaging the leather, which, although thick, can be vulnerable to impacts.
- Lightly clean the surface: Remove any remaining soil with a dry cloth, avoiding excess water, which could encourage mold growth.
- Harvest in dry weather: Professionals advise harvesting on dry days, as humidity encourages rot.
During harvesting, wear gloves to protect yourself from possible thorns on the stem and have padded baskets or containers ready to transport the watermelons. It's important do not stack the fruits excessively and handle the fruit carefully to avoid bruises, cuts or blows.
Storage and preservation after harvest
Once the watermelon is harvested, its Shelf life and quality depend on storage conditions. Inspect each piece to make sure it's free of bruises, cuts, or bruises. Damaged fruit should be eaten first, as its shelf life will be shorter.
Watermelons can be kept at room temperature for a few days. However, if they are not going to be consumed immediately, it is best to store the pieces in a cool, well-ventilated place. The ideal temperature range is between 10 ° C and 16 ° C, with 13°C being the optimal point according to international organizations to prolong freshness without causing internal damage.
Avoid temperatures below 10°C, as they can cause spots, juice loss, and rind necrosis. If the fruit is to be transported, do so in trucks or padded baskets, lining the bottom with straw or hay to prevent chafing and replacing the material whenever necessary. Under these conditions, a well-harvested and stored watermelon can last up to two or three weeks without losing quality.
Frequently Asked Questions About Watermelon Harvesting
- What happens if I harvest watermelon early?
Watermelon doesn't ripen off the plant. If harvested early, its flavor and texture will be bland and mealy. - Do all varieties ripen the same?
No. Some seedless and mini varieties develop basal spot and dry tendril differently. Consult the characteristics of your chosen variety before harvesting. - Can I save watermelon seeds to plant next year?
Yes, but only if the watermelon isn't a hybrid. Remove the seeds from a healthy, ripe fruit, clean them, and let them dry before storing in a dry, dark place. - Why is my watermelon big but not sweet?
This is often the result of overwatering during ripening or insufficient sunlight. Adjust your watering and make sure the plant receives full sun. - How to prevent watermelon from being damaged during harvest?
Use sharp tools and cushion shipping containers. Handle fruit by the ends, never by the stem or tendril.
