Pollinating the pumpkins:
Sometime in late December -January assuming 40 degree heat hasn’t scorched all your plants, your pumpkin plant begins to produce flowers. First male flowers will appear a week or two before the first female comes upon the scene. Some gardeners worry that there is something wrong with the plant, as no females have appeared. This concern can become heightened when talking to experienced growers who boast of pumpkins already on the vine. Your plant to develop female flowers with tiny fruit attached below the flower, but that’s only the beginning. For fruit to set the female needs to be pollinated by the male (d’uh). Usually this is aided by insect pollinators like bees or beneficial beetles. However bee numbers are declining and often our own efforts to keep insects out of the garden are too successful!
Male Flowers (above) are on an erect stem that is fairly thin, and shoots up several inches above the vine. The centre stamen contains the pollen. Pollen is mature ,if it readily comes off the stamen and onto your finger. Do not pick and use it ,until the pollen is mature. There are usually several male flowers for every female flower. There should be a mature male or two ready to pollinate whenever a female matures.
Female flowers(above) are easily identified. A tiny baby pumpkin fruit ( actually an ovary that will develop into fruit once pollinated) is located between the stem and the flower. The female flower will be close to the vine and the stem will only be a couple of inches long. In the centre is a multi segmented stigma which must be pollinated in order for the fruit to develop. The first picture (above) is an immature female. The second picture above shows a mature female with her flower open, and ready to be pollinated.
Pollination has occurred if after several days the female flower has died and fallen off, and the tiny pumpkin beneath it begins to grow. If pollination did not occur, the baby pumpkin below the female flower will shrivel and die.
Pollination needs to be made to all segments of the female flower for the fruit to reach it’s maximum potential, it may even abort. While the bee population is down, many other insects are pollinators. Any insect that is attracted to the pumpkin flower is a potential pollinator. It must travel in the right sequence, from male flower to female flower.
If pesticides are used, you are killing off the pollinators in your area, this is one of the reasons we prefer organic gardening methods.
If you rely on Mother Nature, you will not know the results for several days after the female blooms. For those growing giant pumpkins, every day counts and you do not want to risk failure of the first few fruit, or poor pollination which is often not evident until the fruit has been growing for a while.
By pollinating your pumpkin by hand, you assure a number of things. First, you use pollen from a male pumpkin from a plant you select. It significantly increases the likelihood of successful pollination of the female flower, although nothing is an ironclad guarantee. And, it will increase the likelihood of pollinating all segments of the female flower.
Step by step:
Time pollination for the day that a female flower opens it’s bud. With a little experience, you can usually tell the night before when it is ready to open.
Pollinate the plants in the early morning. The female flowers will close later in the day.
Select a male flower. Pull off the petals to expose the stamen which contains the pollen.
To make sure the pollen is mature. Touch the stamen with your finger and see if tiny yellow specks(the pollen) come off on your hand.
Using the stamen itself (some gardeners transfer it to a soft paint brush). Gently rub the pollen onto the inside stigma of the female flower. Make sure to come in contact with all segments of the stigma. You can leave the stamen inside the female flower but it’s not necessary.
Hand pollination is now complete! You should plan on pollinating several fruit on each vine. Later on, you can select which ones to keep. The best fruit are those with five or six sections to the stigma in the female flower.
After a day, the female pumpkin flower will fade away…