Watermelon tolerates hot weather, and requires more heat than most vegetables. Plants thrive at temperatures ranging from 25°C to 30°C, which is also favorable for seed germination. Plants do best on fertile sandy loam or loam soil with good drainage and a pH level of 5.6 to 8.0.

Varieties available

Buffalo – This is an early yielding variety, with vigorous, high-round and dark green fruits. The rind is thin but very tough, making it ideal for shipping; sugar content is around 12-14%. A fruit weighs between 12 kilograms (kgs) to 15 kgs. This variety performs better in hot and dry conditions and is adaptable to all types of soil.

Diana – A unique, golden yellow skinned, oval-shaped fruit with a soft and juicy texture. This is excellent for the high-class markets with brix averages of 12 to 14 %, and a fruit weighing from 2 kg to 4 kg, depending on fruit selection. A plant matures from 60-65 days after sowing.

Drexler Tayan proudly posing with Diana
watermelon variety.

Tiffany – This variety is a delicate fruit with crisp, juicy, and creamy sunshiny-yellow flesh. It produces dark green fruits with oval shape, with brix averages of 12-14 %, and with a fruit weight of 2-4 kg, depending on fruit selection. A plant matures from 60-65 days after transplanting.

Seedling care

Soak the seeds in clean water for 30 minutes to 1 hour and wrap them in a wet cloth or towel.

Place the cloth in an improvised or covered container which can keep the temperature within 25°C to 30°C until the seeds sprout. Twenty-four to thirty hours is enough to germinate the seeds. Plant 1 pre-germinated seed in each hole of the seedling tray with 104 holes (seedling trays are available at Harbest Agribusiness Corp). Make sure that the root is facing downward. Cover with moist soil and water the seeds once or twice daily; in such case, damping off occurs. Apply systemic fungicide for seedlings. Seedlings must be exposed to sunlight 6-8 hours a day. To prevent strong wind and heavy rain, use plastic or fine net to protect the seedlings.

Land preparation

Plow and clean the planting area. Use 1 m bed, 0.5 m canal, and a crawling area of 4 m. The bed should be 15-20 cm high above the fertilized level. Use plastic mulch to prevent growth of weeds, retain soil moisture and avoid soil erosion.

Transplanting 

Watermelon can be planted directly to the field or grown in seedling trays, before being transplanted to the field 10-12 days after sowing (transplanting can be done after 2-4 true leaves emerged). This should be done late in the afternoon.

Fertilization

Fertilization per 20 meter linear bed.

Use 2 sacks of organic matter–processed chicken dung or any commercially-available organic fertilizers; 150 g Boron, 4 kilos of complete fertilizer (NPK 14-14-14), 1 kg Calcuim Nitrate, and 150 g Magnesium.

Practice drenching for additional support of fertilizers for growth boosting and easy absorption of the plants.

Drenching schedule

Drenching should be done 7 to 10 days after planting. The mixture of fertilizers is diluted in 16 L of water. One-hundred fifty milliliter of the solution is applied to the soil, on the base of each plant.

Irrigation and drainage

Irrigation should be applied frequently to prevent the plant from injuries in very dry soils. Water consistently as soon as the flower buds start to form. Observe drainage during the wet season. Withhold the water supply as soon as the female flower appears in order to improve fruit setting. When the fruits start to develop, more water is required to produce good-sized fruits. It is best to withhold or reduce irrigation when fruits reach their full size during the ripening stage.

Pruning and fruit setting, and pollination

Watermelons require pruning to improve the fruit setting and harvesting. Cutting of the 4th true leaf should be done to develop 3 laterals or 3 secondary vines. Remove the flowers and vines in each primary vine from the 5th node below.

Manual pollination is required during unfavorable weather conditions or rainy season due to the absence of pollinators. Maintain 1 or 2 fruits per plant for your desired size.

Harvest

A grower must be familiar with the variety that he is planting to determine the best stage for harvesting. These pointers may serve as reference for watermelon ripeness:
• Count the number of days after the flowering.
• An unripe fruit is heavy while a ripe fruit is lighter; an overripe fruit is lightest.
• Tap the watermelon on the center with your knuckle – if it sounds like you are tapping your forehead, it is unripe; if it sounds like your chest, then it is ripe. Moreover, if it sounds like your stomach, it is overripe.

Buffalo, Diana and Tiffany watermelons are products of KnownYou Seed Philippines, Inc. For inquiries and orders, please call (0917) 320-1689 (Globe) or (0999) 968-0630 (Smart and Sun), fax (075) 632-1785 or email kyp@knownyou.com . Visit us on facebook at www.facebook.com/kyp168.

This appeared in Agriculture Monthly’s October 2018 issue.