Be a Bee! Hand pollinating pumpkins and squash
There are times when pumpkins, winter and summer squash and zucchini don’t produce as many fruits as wanted. This may be that the female flowers are not getting fertilized. These vegetables all bloom quite early in the morning and the flowers close up by early mid-morning. Bumblebees and other native bees tend to be active and visiting flowers early in the morning when these flowers are open. Honeybees tend to be less active in the cool or the morning and become active late in the morning and during the day. Since we are seeing declines in some bumblebee and native bee populations the problem might be a shortage of the right pollinators.
Home gardeners can pollinate their own pumpkins, winter and summer squash and zucchini in place of the bees doing it. It is very easy to do and takes very little time. It can be a fun activity for children. I know mine loved to do it when they will little. But first a little information about these plants will help gardeners achieve success with their own pollination efforts.
First – These plants are all known as being diecsious. This means that they have both male and female flowers, all on the same plant. When one looks into the open male flower, you will see a single fingerlike structure (called a stamen) covered with golden pollen dust. When looking into a female flower, you will see curled structures (called the stigma) clustered together in the center of the flower. The female flower will also have a tiny fruit right below the flower on the stem.
Second – These flowers are only open for one day for a few hours. Early morning pollination is the only time for it to take place.
Third – When the plants begin to flower, they will produce mostly all male flowers. These are usually located close to where the plant is rooted and on a tall, long stem. After a week the plants will begin to produce the female flowers which are located towards the ends of the vines. Be patient and check the plants to see when the female flowers begin to open.
Fourth – Encourage the increase of native pollinators. Plant annual and perennial flowers to provide them with other food sources. Put up bee nest structures. Plans for these can be found on the internet or call the Extension Office for information on making them. Try to avoid using insecticides as much as possible. Remember, the insecticide kills all insects, the target ones and the beneficial good ones. If an insecticide is necessary, select one with the least injury to bees, and spray late in the evening when they are in their nests.
To hand pollinate, pick a male flower that is fully open and has pollen visible. Peel all of the petals off the flower leaving the stem, flower base and the pollen bearing structure (stamen). Then push this pollen-bearing structure down into an open female flower and rub pollen on the structures in the center of the flower (stigma). A male flower may be used for a couple of female flowers, but if there are enough male flowers, pick a new one for each female flower to be pollinated. If pollination was successful, the female flower will close, dry up and drop off in about a week and the small fruit will remain and will begin to grow. If unsuccessful, the small fruit will soften, turn yellow and drop off with the flower.
Last, if you want to try something new, save the yellow petals from the male flowers used to pollinate and pick those which are not being used to pollinate and peel the yellow petals off as well. Use them in salads or they can be added into a number of different dishes. A quick check on the internet will give you a number of recipes for their use in cooking.
Have fun “Being a Bee” and enjoy.
Ken Eraas is horticulture assistant with NDSU Extension Service/Ward County.