Watermelon Pollinating Procedures
Watermelons (Citrullus lanatus) like many other melons, cannot produce fruit if they are not pollinated. A watermelon plant is a cucurbit and as such bloom with both male and female flowers and can be pollinated without the help of another watermelon plant. In order to pollinate the watermelon plant, pollen from the male flowers must make its way to the female flowers by one method or another.
Watermelon in nature is pollinated by bees, wasps and other nectar seeking insects who hop from flower to flower and distribute pollen. Watermelon farms rely on bees to pollinate the crop and farmers will hire and raise bees just to perform this service. Since the watermelon flowers open only for a short time, it is essential that bees are present when they do. It is also essential that other, more fragrant plants are not available in or around the watermelon growing area, or they may attract the bees away from the work at hand. A calculation of one bee per 100 watermelon flowers is a typical goal for farmers to maintain. This allows for a loss of certain numbers of bees to other flowering plants but is far from foolproof.
Manual Pollination Preparation
When you are growing watermelons indoors using a greenhouse or polytunnel, or if the bee and wasp population in your growing area is not sufficient to pollinate the plants naturally, you can do so by hand. Male watermelon flowers are pollen producers and female watermelon flowers are fruit bearing. Watch for the appearance of male flowers in the spring months. They are discernible by the large stamens located at their center when open. When the male flowers do appear, it is a sign that the female flowers are coming soon after. Watch carefully for the female flowers since they open for one day per growing season and once they are gone, you cannot pollinate the plant.
Performing Manual Pollination
During the early morning hours on the day that the female flowers do open, manual pollination can be performed. The female flowers are recognizable by their lack of stamens, and should be pollinated between the hours of six and nine o'clock in the morning for the best results. Start the manual pollination process by removing the petals from a male flower, then bending its stalk toward the female flower. Gently brush the male stamens against the center of the female flower to create a transfer of pollen. Each male flower is capable of pollinating up to four female flowers. Use a brush to pick up the pollen and place it if you find doing so by hand to be too damaging to the flowers.
Once pollinated, a watermelon will bear fruit within four months. If you are growing your watermelon inside a polytunnel or greenhouse this time can be reduced significantly. The fruit forms just below the female flower bud and grows along the ground until it reaches maturity and is harvested. Warm summer weather and average watering are all that is required to develop edible fruit once the plant is pollinated.
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