Watermelon
(Citrullus lanatus)
Watermelon, locally known as pakwan or sandia, is one of the more popular fruit vegetables in the Philippines, especially during summer.
Preferred varieties are Sugar Baby and Charleston Gray. Varieties with yellow flesh and rind are not very popular.
Watermelon is planted to about 5,000 ha, the bulk of which is planted during the regular season (October to January) There are a few commercial growers during the off-season in Marinduque, Sorsogon and Pampanga.
Varieties
Watermelon has the following varieties
* Sugar Baby : round and dark green with red flesh.
* Goody Ball : round and dark green with red flesh.
* Charleston Gray : oblong and light green with red flesh.
* Maharlika : round and dark green with red flesh.
Soil Requirements
Watermelon grows best in dry, hot areas. It is best to plant before December. With proper management, watermelon can be grown in clay soils. Production is best, however, in sandy loam to clay loam soil.
Land Preparation
Prepare the soil thoroughly by plowing and harrowing twice. Prepare adjacent beds 0.75-1.0 wide. In between the beds, provide a space 0.5 m wide as canal for furrow irrigation, or as a pathwalk for manual watering. The next adjacent bed should be 5-7m from center to center of the canal.
Apply 5-10 t/ha animal manure and 5-7 bags/ha of complete fertilizer (14-14-14) several days before planting. Cover with plastic mulch, perforated 0.4-0.5 m apart.
Planting and Maintenance
Seedling Production
A 1-ha production area requires 300-500 g seeds or 6,000 to 10,000 seedlings. Soak seeds in water for 30 min and wrap in damp cloth overnight. Sow singly in 4 x 6 (inches) plastic bags with 1 part garden soil, 1 part animal manure or compost and part rice hull ask or wood ash. Place in partial shade and expose to full sunlight one week before transplanting.
Irrigate before transplanting. Transplant one seedling per hill. Irrigate immediately. Plant corn as trap crop and windbreak every 10-15m. Plant marigold as pest repellant.
Pruning and Fruit Thinning
Pinch off the main shoot after the 5th node. Allow two major vines to develop. Remove the first female flowers or fruits on the major vines. Allow 2-3 fruits/vine on the 10th and 12th nodes and thin to 1-2 fruits /vine depending on variety.
Nutrient and Water Management
Side-dress with 10-20 g/hill 14-14-14 every two weeks until the onset of female flowers. At fruit setting, side-dress with 10 g urea (46-0-0) and muriate of potash (0-0-60) at 1:1 ration 2 to 3 times every two weeks.
Irrigate regularly at 7-10 days interval or depending on the growth of the plants. Stop irrigation two weeks before harvesting.
Pest and Disease Management
* Cucurbit beetle : Spread wood ash; spray carbamates
* Cutworm : Spray tobacco extract or Bacillus thuringiensis
* Aphid/thrips : Use plastic mulch; spray hot pepper extract
* Leaf miner : Spray fipronil or Chlorox
* Downy mildew : Spray with mancozeb/Acrobat; spray with compost tea (Compost tea is prepared by fermenting compost for 10-14 days. The effluent is sprayed to control foliar disease).
* Anthractose : Spray with captan/Bentale; spray with compost tea
Harvesting
Harvest at 75 to 85 days from transplanting depending on variety. The indices of maturity are dried tendrils near a fruit and yellowing of the blossom end.
Source: PCARRD Production Guideo on Watermelon; photo from www.ashycook.topcities.com