How do pumpkins pollinate

This worry is heightened when talking with experienced growers who will be a week or two ahead of novice growers, and boast of pumpkins already growing on the vine. Never fear, your pumpkin plant will eventually develop female flowers with tiny fruit attached below the flower. Male Flowers above are on an erect stem that is fairly thin, and shoots up several inches above the vine. The center stamen contains the pollen.

Do not pick and use it, until the pollen is mature. Pollen is mature, if it readily comes off the stamen and onto your finger. 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 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, at most. In the center of the pumpkin flower, is a multi segmented stigma. This stigma must be pollinated in order for the fruit to develop. The first picture above is an immature female closed flower.

The second picture above, shows a mature female with her flower open, and ready to be pollinated. The affirmative answer is discovered after several days, when the female flower has died and fallen off, and the tiny pumpkin beneath it begins to grow. Poor pollination can also occur. Pollination needs to be made to all segments of the female flower. It may even abort. While the honey 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 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.

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. To learn more about pollination, check out The Pollination Scene While this site does not speak to pollinating pumpkins in particular, the content on the site is very thorough and it provides a wealth of links to other sites on pollination.

Jokes about hand pollination abound, both in the internet and in the field. Does anyone object to helping their plant to have sex? Okay, with that said, on to the learning…. 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 versus Mother Nature- -random? This eliminates breeding a giant pumpkin with a nearby Zucchini Squash. Second, it significantly increases the likelihood of successful pollination of the female flower, although nothing is an ironclad guarantee. Third, it will increase the likelihood of pollinating all segments of the female flower.

Tip: To increase the likelihood of hand pollination by the desired pollen, put a nylon stocking, a fine screen, or other cover over the female flower the night before pollination. After hand pollination, re-cover the flower. Be careful not to damage the flower, especially the stigma. Cross Pollination from one plant of the same variety to another is good and healthy for a species.

Cross pollination of one variety to another variety in the same family can be good if you are experimenting with, or attempting to create new varieties or disease resistant strains. It can be bad, if you are trying to grow a pumpkin, and a cross with a Zucchini occurs. In the first instance, cross pollination in nature exists to broaden the gene pool of a particular species, be it animal including humans or plants.

The broader the gene pool, the more likely a subset of the population will survive some future disease or bacteria. This includes disease resistance, size, taste, nutritional value, etc. The resulting hybrids are then made broadly available in agriculture. Watch for insects visiting the blossoms, especially squash bees, bumblebees and honeybees. They're all effective pollinators. You can also visually inspect the female blossoms for pollen sticking to their stigmas and check the pumpkin buds for growth once the blossoms have begun to shrivel.

Encouraging healthy populations of pollinators helps your yields greatly. Provide other pollen sources early in the season, before your pumpkin or squash blossoms are available, and avoid the use of systemic pesticides that indiscriminately kill bees as well as pests. Native squash bees and bumblebees often hibernate in the soil during cold weather and build their nests there in-season, so don't till or cultivate too aggressively in your pumpkin patch.

One way to know for sure your blossoms are pollinated is to do it yourself. In the early morning, while the blossoms are open, snip a male blossom from the vine and break away its petals to reveal the anther. Use this as a sort of paintbrush to dab pollen onto several female blossoms, then repeat with a new flower. If you don't want to break off the male blossoms, you can use a paintbrush or even a cotton swab to transfer pollen from the male to female blossoms.

Repeat this process over a period of days, pollinating the female blossoms with pollen from the males, until the blossoms naturally begin to shrivel away. You should see good fruit set as a result. A couple of potential problems can interfere with the growth of your pumpkins. Let's Stay Connected. By entering your email, you consent to receive communications from Penn State Extension.

View our privacy policy. Thank you for your submission! Home Pumpkin Pollinators. Pumpkin Pollinators. Pumpkin fruit set can be affected by a number of production and environmental factors.

Squash bee by Susan Ellis, Bugwood. Honeybees - Apis mellifera Although honeybees are regarded as important pollinators for a wide variety of crops, there are several other bee species that are effective pollinators of pumpkins. Bumblebees - Bombus spp. Squash bees - Peponapis pruinosa The most important pumpkin pollinator is the squash bee, a naturalized solitary species that is dependent solely on pollen from pumpkin and squash plants.

Pesticide application Pesticides, especially insecticides, can kill bees. Bibliography Tepedino, V. The pollination efficiency of the squash bee Peponapis pruinosa and the honeybee Apis mellifera on Summer Squash Cucurbita pepo. Journal of the Kansas Entomological Society, Julier, H. Wild bee abundance and pollination service in cultivated pumpkins: farm management, nesting behaviour, and landscape effects. Ecology and Behaviour, National Research Council. Status of Pollinators in North America.

Shuler, R. Field and Forage Crops, Burgett, D. Evaluating Honey Bee Colonies for Pollination. Winfree, R. Wild bee pollinators provide the majority of crop visitation across land-use gradients in New Jersey and Pennsylvania, USA. Journal of Applied Ecology. Donovall, L. Journal of the Kansas Entomological Society. In Press. Frankie, G. Bees in Berkley? Fremontia, Williams, R. Wood, M. Pictures by A. Why do we need this? Entering your postal code will help us provide news or event updates for your area.

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