If you have a pumpkin vine growing in your garden, you may have asked the same questions that we have asked ourselves many times. "Why is my pumpkin vine producing so many flowers, but not as much fruit?" and "Why are the flowers shriveling and falling off?"
Just the other day, I was walking around with our supervisor Panditji, and when I admired the pumpkin vines, he said "Kucch baat nahin ban rahin. Phool toh bahut lagte hain, par pata nahin kyun, kaddu zyaada nahin lag rahe"!
So what exactly is going on with these pumpkin vines? Well, the pumpkin vine has male and female flowers. Yes, two different sexes on two different types of flowers! The flowers that are first to bloom are the male ones, and then a week later the female flowers make an appearance.
You can recognize the male flower because it grows on a thin stalk, stands up tall to attract the attention of the pollinators, and perishes within 24 hours. These are the flowers which we see wilting and falling off. But we need not be worried about that because they are more numerous than the female flowers, and keep on blossoming every day.
The female flower grows closer to the ground on a lateral and thick stalk which can bear the weight of the pumpkin. It also has a bulbous structure at the base of the flower which is its ovary. In the event of pollination, this ovary will develop into a pumpkin!
In the rare case, when there is a complete lack of pollinators, you may find a lot of male and female flowers in your garden, but no fruit production. In the short term, this problem can be solved by hand pollinating the female flowers. Just break off the male flowers, tear aside its petals, take the pollen covered stamen and rub it against the stigma of the female flower, as shown in the diagram below. This should be done early in the morning when the male flower has just opened, and the pollen is clearly visible.
In the long run, however, you must ensure there are enough pollinators in your garden. Create a hospitable environment for them by banning all toxic chemical usage, and perhaps introducing a beehive or two. Hand pollinating pumpkins is really quite ridiculous. Pollination is an act of nature and should be occurring on its own without any interference from us humans.