Watermelon

Watermelon is a heat-loving annual crop belonging to the Cucurbitaceae family. Sowing is conducted when soil temperatures at a depth of 10 cm consistently reach +14...+16 °C, typically during May.

In regions with short growing seasons, transplanting seedlings is common. Seedlings are typically raised for 25–30 days and transplanted into the open field once the risk of spring frost has completely passed.

Plant spacing depends on the variety and irrigation system used, with row spacing usually ranging from 1.4 to 2.1 meters to ensure adequate space for vine growth.

Seed planting depth for direct seeding ranges between 4–6 cm, depending on soil texture. Lighter sandy soils require slightly deeper placement to ensure consistent seed-to-soil moisture contact.

Depending on the cultivation intensity, the optimal plant population density typically ranges from 6,000 to 10,000 plants per hectare.

Watermelon is highly thermophilic, with an optimal temperature range for active growth and fruit development between +25...+30 °C. Temperatures below +15 °C significantly hinder the plant's metabolic processes.

The crop requires intense sunlight throughout its life cycle. Any form of shading during the growing phase can negatively impact fruit set and result in smaller, lower-quality yields.

Well-drained sandy or sandy-loam soils with a neutral pH are ideal for watermelon. Heavy clay soils should be avoided as they increase the risk of root rots and waterlogging.

Although the plant has a deep root system that provides drought resistance, supplemental irrigation via drip systems is essential for maximizing yield and fruit sugar content.

Crop rotation is critical. Watermelons perform best after cereal crops like winter wheat. Planting should be avoided in fields previously used for other cucurbits or solanaceous crops to prevent soil-borne pathogens.

The crop is vulnerable to various fungal diseases. Alternaria leaf blight and Anthracnose are common issues, particularly in high-humidity conditions, causing significant leaf tissue necrosis.

Vascular diseases such as Verticillium wilt and Rhizoctonia root rot can cause rapid plant collapse and death. Sclerotinia, or white mold, is also a serious threat requiring strict field sanitation.

Viral diseases, including Squash mosaic virus, Papaya ringspot virus, and Watermelon mosaic virus, are major concerns because they are transmitted by insect vectors and cannot be cured.

Common insect pests such as leaf beetles, weevils, and various plant bugs like the Eurygaster integriceps can cause significant damage to foliage and developing fruit.

Integrated Pest Management (IPM) is necessary, involving the use of certified disease-free seeds, weed control to eliminate insect reservoirs, and targeted fungicide applications during high-risk periods.

Harvesting begins when the fruit reaches maturity. Key indicators include the drying of the tendril near the fruit attachment point and the development of a dull sound upon tapping.

Harvesting is best done in the early morning to minimize solar heat accumulation in the fruit, which helps maintain freshness and extends potential shelf life.

Fruits are harvested by cutting the stem with a sharp knife or shears, leaving 3–5 cm of the stem attached to the fruit to protect the rind from decay.

Careful post-harvest handling is vital, as bruises and rind punctures lead to rapid secondary bacterial and fungal infections during transportation and storage.

For temporary storage, watermelons should be kept in well-ventilated conditions at approximately +4...+8 °C, ensuring sufficient airflow to keep the rind dry and healthy.