Agriculture, Fisheries and Conservation Department



Specialty vegetable crops

Technical Development

Premium Vegetables

Organic Watermelon

Growing Organic Watermelon
Cultivation Environment : Watermelon likes hot weather (optimum temperature for growth: 25 ~ 30 degrees), adequate sunlight and dry air. The most suitable soil is sandy loam with a pH value of 5.0 ~ 6.8 and with rich organic matters, good drainage and ventilation.
Planting and Spacing :

Transplanting method is preferred. Put seeds in an environment of 28 ~ 30 degrees for germination before sowing. When seedlings come to 3 to 5 true leaves (about 15 ~ 20 days), they can be transplanted to the field. Ways of planting:

i. Seedlings can be planted in single or double rows near the edges of a planting bed of 3 m wide so that vines can grow horizontally. Plant spacing is about 1 ~ 1.2 m, and row spacing 3 m; or

ii. Seedlings can be planted at the centre of a planting bed of 0.75 m wide so that vines can grow vertically. Plant spacing is about 1 m, and row spacing 1.5 m.

Application of Fertilizer and Management :
Basal dressing :

Apply 1,000 kg compost, 90 kg peanut cake and bone meal each per d.c..
(1 d.c.= 674 square metres or 7,260 square feet)

Top dressing :

Apply organic liquid fertiliser of the right proportion (e.g. nitrogenous peanut cake or fish meal solution) one week after transplanting, and then once every week until the fruits are fully grown.

From the flowering to initial fruiting period, carry out bunch fertilization for three times by applying 30 g organic fertilizer (N:P:K=4:3:3), and 8 g bone meal and natural potassium fertilizer (50%K2O) each to the side of the plant.

Irrigation : Watermelon tolerates dryness but not wetness. The water in soil should be maintained at 70% throughout the whole growing period. Watermelons should be planted in rainproof shed in rainy weather.
Training :

Train the vines to avoid wasting nutrients. Fruits are kept when the plant is growing vigorously. Female flowers which are on too high or too low a node should not be kept for fruiting. For large fruit varieties, 1 ~ 2 fruits are kept on each vine while for small fruit varieties, 3 ~ 4 fruits are kept.

Harvesting :

The growing period of watermelon depends on the variety used. It normally takes about 75 ~ 85 days for the small fruit type, and 95 ~ 100 days for the large fruit type, to grow from the transplanting to maturity stage.

Watermelon should be harvested as soon as it matures.



Horticulture Section, AFCD






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Last Review Date : 11 July 2018