Cultivation, Quality, and Nutrition of Watermelon
Watermelon is a fruit native to Africa, which has become an essential part of human nutrition thanks to its high water content, richness in micronutrients such as lycopene, and low caloric value.
China is the world’s leading producer, followed by India, Turkey, and Algeria. In Europe, Italy and Spain are among the top producers, with Italy’s main growing areas located in Lazio, Apulia, Campania, Lombardy, and Emilia-Romagna.
Italy enjoys an excellent international reputation for the quality of its watermelons, which are exported mainly to Germany, France, and the United Kingdom. Notably, the “Anguria Reggiana” holds the distinction of being Europe’s only PGI (Protected Geographical Indication) watermelon.
Growing Conditions and Challenges
With the progressive increase in global temperatures, watermelon consumption is expected to rise significantly, as this fruit is considered the ideal “summer fruit” to counteract extreme heat.
The market is currently undergoing a transformation driven by seedless varieties—a fast-growing segment (e.g., Perla Nera)—and mini watermelons, which better match modern consumer preferences.
In addition to fungal diseases and pathogens, another major issue is sunburn on the rind, which promotes rot and often makes the fruit unsellable.
Nutritional Recommendations for Watermelon
During the post-transplant phase, it is important to support root establishment while minimizing negative effects caused by unfavorable climatic conditions, such as temperature fluctuations or drought.
Stimulating the plant during flowering and fruit set with seaweed extracts, micronutrients, and plant-based amino acids is crucial to maximize yield.
Calcium and phosphorus strengthen plant tissues and cell walls, reducing cracking and improving shelf life. Special attention should be given to potassium fertilization, as sugar content (Brix degree) is a key quality parameter.
It is also good practice to use products containing microbial consortia to revitalize depleted soils and reduce susceptibility to diseases. Providing potassium in the right form (without nitrogen) is essential to obtain sweet, high-quality fruits.
Below you will find the most effective strategies for optimal fertilization of watermelon.
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Irrigation management is essential to prevent fruit cracking. Nutrients such as phosphorus and calcium (Leaf P-Ca) strengthen cell tissues and contribute to fruit robustness. Products containing glycine betaine, betaines, and proline also help maintain water balance inside the fruit (Leaf K).
Sugar content is important in watermelon because, besides ensuring higher fruit weight, it is an indicator of production quality. Potassium nutrition must be well balanced: excess can cause poor storage and overripening, while deficiency results in less flavorful fruits with too much white (rather than red) flesh. Leaf K supports the accumulation of sugars as it contains highly assimilable potassium with acidic reaction.
Sunburn on the watermelon rind is mainly caused by excessive direct sunlight. Prevention can include:
- Products that strengthen the rind (Leaf P-Ca, Magnetical, Focus Ca)
- Reflective products, mainly zinc-based
- Protective coating products (kaolin)